— Collingwood & St Kilda drew in the 2010 AFL grand final
— Sachin Tendulkar played his 200th test match
— Essendon defeated Collingwood in 2009 Anzac Day clash thanks a last-minute goal kicked by David Zaharakis
— Shane Warne earned his 700th test wicket in 2006
— Michael Jackson, Don Bradman, Tony Greig, Richie Benaud, Prince, Avicii, Carrie Fisher were still alive
By the time I die I will miss out on:
— Birth of my grandchildren, great grandchildren, great great grandchildren and so on for infinitely many generations and how they will live their lives as human beings
— Winners and losers of sporting competitions like Olympics, AFL, NRL, Cricket / FIFA World Cup and Asian Cup
— Deaths and Births of people like celebrities
— Retirements of my favourite athletes and sportspeople
— Discovery of new organisms, bacteria and viruses
— New trends and viral videos humans will find popular
— Future scientific, archeological and historical discoveries announced on TV
— New youtube videos, articles, websites created on social media for us to watch, read, laugh and react.
— New TV series, documentaries, cartoons, animations (anime), porn
— New photos, videos, tweets, statuses for us to like, dislike and share
— New blog posts to read
— New games for humans and animals to play
— New products advertised like clothes, accessories, makeup, electronics, fashion, furniture, footwear, fitness devices
— New dishes, cultures, traditions created
— New inventions, infrastructure and facilities along with enhanced technology e.g. Space elevator?
— New drugs, laws, policies, and changes to housing market and the economy
— __ of the year headlines and prestigious awards e.g. Word, player, Animal, Man, Woman, Movie, Show
— New words, phrases, idioms, proverbs, poems, stories, novels, literal devices
— New suburbs like Mount Atkinson, towns in rural and urban areas during urban sprawl, new countries, old countries disbanded
— New rail corridors with rail stations
— New infrastructure projects, facilities, educational programs, sporting grounds, buildings,
— New conflicts made, Old conflicts resolved
— New tribute posts to celebrities, influential people like entrepreneurs, scientists, politicians, activists, athletes, sports personnel,
— Droughts being broken, upsets in sports and academic competitions
— TV shows beginning and ending
— New movies, films, songs, soaps, concerts,
— New annoying ads from food outlets, political parties during election years, entrepreneurs, car companies, tech brands,
— New world records being formed and broken
— New theories and hypothesis about different topics
— Newly elected leaders,
— Future global wars
— Birth of new animal and bacterial species or living organisms
— Future Meteorites & Meteors hitting Earth’s atmosphere and surface
— Future space expeditions, spaceships being launched, future discoveries in outer space
— Future major weather events like droughts, ice age, tornadoes, hurricanes, thunderstorms
— The day all ice caps, Arctics and Antarctica on North and South Poles will melt flooding Earth
Probably when I reach the terminal stages of my life, I might have a good idea of where I may be buried. I expect my best friends, children, grandchildren, relatives, nieces, nephews, cousins etc. to attend my funeral. But I don’t know who else may be there. Although I will be laying in a casket, silent and still, I’m curious to know what will the speakers say about me, the type of life I lived, the type of person I was, how I contributed to society and how I inspired others to be like me. After all the flower veils are laid upon my coffin, who will carry my coffin to the funeral van? What song will be played as my coffin is escorted away to its final resting place a few metres underground alongside other anonymous corpses? Will there be any valuable and prized possessions laid by my dead side like a toy, letter, puzzle etc.? Finally if my children, grandchildren, great grandchildren and so on does visit my tombstone, what will they say as their tears trickle down their cheeks?
I have missed out on seeing so many landmarks due to natural erosion, natural disasters, gravity such as:
— Old Man of the Mounting in the White Mountains, New Hampshire
— Washington Sequoia Tree in Sequoia National Park, California
— Jeffrey Pine in Yosemite National Park, California
— Duckbill in Cape Kiwanda State Natural Area, Oregon
— Jump-off Joe in Newport, Oregon
— Wall Arch in Arches National Park, Utah
— El Dedo De Dios or “God’s Finger” in Canary Island, Spain
— Eye of the Needle near Fort Benton, Montana
— “Goblin” Sandstorm formation in Goblin Valley State Park, Utah
In the future, currently standing famous landmarks that may disappear such as:
https://en.wikipedia.org/wiki/Time_pyramid
The Time Pyramid is a work of public act by Manfred Laber currently under construction in Wemding, Germany. On its 1200th anniversary is 1993, the first concrete block was laid and one block is added to the pyramid every 10 years. So far the first 3 blocks have already been laid and the next one will be laid on October 2023. Once completed the pyramid will consist of 120 blocks, each block measuring 1.2m long, 1.2m wide and 1.8m tall. Adjacent blocks are separated by gaps of a half a block or 0.6m. The pyramid won’t be complete until the year 3193.
https://en.wikipedia.org/wiki/Longplayer
On January 1st 2000, Jem Finer composed Longplayer based on an existing piece of music, 20 mins and 20 secs long, which is processed by a computer using a simple algorithm. This yields a large number of variations, which, when played consecutively., gives a total expected runtime of 1000 years. So Longplayer will continue playing until January 1st 3000. You can hear Longplayer by clicking on the link below.
https://www.youtube.com/watch?v=NhEI3FEvxU0
I’m quite optimistic that scientists and medical researchers will find cures and effective treatments for all types of cancers, diseases and syndromes. As the knowledge of the pathology, biochemistry, genetics and microbiology of our incurable diseases increases, the day that a cure is officially designed, mass produced and sold to the pharmaceutical market ready to be prescribed is closely approaching us. Along with advancing technology, neuroscientists are conducting trials using machines, robots and electronic devices to cure patients with chronic neural diseases, syndromes and neural injuries like spinal cord paralysis, ADHD, Brain injury and Alzheimer’s Disease. As humans’ life expectancy increases every generation thanks to higher living standards, access to clean food, water and shelter, residing adjacent to health, education and transport facilities, would there be a time when we can physically, biologically or medicinally reverse ageing? If so, does this make immortality theoretically possible? Technologies like CRISPR/Cas9 have demonstrated promise in repairing damaged or mutated DNA back to the original genome around the patient’s younger years but it still needs improvement. But I don’t know I’ll be alive to be aware of the news every human on Earth is desperately waiting for regarding cancer treatment. It’s difficult to predict when exactly that momentous day will happen but some scientists predict that day may occur around the 2040s. However, scientists are racing against time to perfect the technology before more lives are lost to cancer and diseases. It’s depressing that after you yourself pass away, the cells that make up your body continue to live on like nothing has happened until they are deprived of Oxygen and Glucose. Cancer researchers have found evidence that telomeres and telomerase may hold the key to unlocking the limitless proliferation and immortal life of cancer cells. But manipulating this genetic trademark and implementing it into healthy cells without compromising their normal function is a challenge scientists are trying to overcome at the moment. I don’t know when that day will come when immortal cells can be implemented safely into your body substituting for dead or tumour cells without eliciting a graft rejection due to your innate and adaptive immune systems or other harmful side-effects. But I remain optimistic that day will come, probably after I die but only time will tell.
— What are the next steps of human evolution?
— What will humans and animals look like in the infinite future?
— What features would we gain and lose over time?
— What influences would cause these evolutionary changes?
Thanks to gene enhancement and technological implants, some people are receiving life-saving upgrades from robotics and genetic engineering, rather than from Darwinian evolution. We might have genetically enhanced humans, bionic men or uploaded beings but it’s evident advancement in technology is beginning to shape human development.
Places currently inhabitable include war zones, exclusion zones, natural disaster regions, sweltering deserts and mountain ranges like snowy peaks and active volcanoes. One notable place is Chernobyl, on the outskirts of Pripyat which is situated 169 km north of Kiev. It’s been 32 years since the 1986 nuclear meltdown occurred that forced the evacuation of local residents, workers and survivors of the catastrophe within a 32 km radius Exclusion Zone. Every year more than 10,000 tourists now explore the disaster site every year, snapping photos at the stricken power plant, abandoned buildings and houses of a real ghost town which you usually see in horror movies. The defunct power plant is now covered by a thick concrete abomination to minimise radioactive material being spilled out into the atmosphere. If you visit this area, you are under no circumstances to sit down or touch anything within this zone including the murky water. You will be screened and checked for any radioactive particles before you enter and leave the area. Right now crews are currently maintaining the concrete sarcophagus that keeps the exploded reactor in check work. Crew members take turns strictly monitoring the damaged reactor 5 hours a day over the course, then take 15 days off work in order to be not exceed the maximum According to Ukrainian officials, the city of Pripyat won’t be habitable for another 20,000 years. So by the year 22,000, a majority of the radioactive particles would have decayed to an adequately safe level, then it may be safe for people to live, work, rest and play in Pripyat inside the exclusion zone without the protection of radioactivity suits. I certainly won’t be alive by the year 22,000 and I don’t know whether my family name will continue for another 2,000 generations.
https://en.wikipedia.org/wiki/Endangered_species
https://www.worldwildlife.org/species/directory?direction=desc&sort=extinction_status
https://a-z-animals.com/animals/endangered/
Which animals would be extinct or become endangered?
Natural selection and evolution drives certain endangered animal species to extinction. Poaching, hunting, climate change and deforestation contribute to loss of habitats, environmental pollution and massacres of exclusively found creatures. Very few animals leave a fossil record behind and everything we could have learned from them disappears with their extinction. According to the International Union for Conservation of Nature and Natural Resources, here are some animals that are at risk of extinction within then next 100 years:
- Rhinoceros (Dicerorhinus Sumatrensis, Sumatran; Indian) = As the only Asian rhino with 2 horns, the Sumatran Rhinoceros is the smallest in the rhino family. It lives in isolated pockets of dense mountain forests in Malaysia, Indonesia and possibly Myanmar (Burma). Along with the Javan rhino, their numbers are greatly threatened by poachers who mainly hunt for their horns.
- Gorilla (Eastern, Western, Western Lowland, Eastern Lowland, Mountain)
- Orangutan (Sumatran, Tapanuli)
- Red Wolf
- African Wild Dog
- Albatross
- Armadillo
- Axolotl
- Aye Aye
- Bactrian Camel
- Bandicoot
- Butterfly Fish
- Chimpanzee
- Chinchilla
- Dhole
- Fishing Cat
- Fossa
- Galapagos Tortoise
- Giraffe
- Golden Lion Tamarin
- Honey Bee
- Hummingbird
- Indri
- Kakapo
- Macaw
- Manatee
- Markhor
- Mongoose
- Numbat
- Parrot
- Pied Tamarin
- Proboscis Monkey
- Red Panda
- River Dolphin
- Sea Otter
- Sea Turtle
- Seahorse
- Sloth
- Tapir
- Tarsier
- Tortoise
- Vulture
- Water Buffalo
- Wildebeest
- Wombat
- Zebra
https://en.wikipedia.org/wiki/Endangered_species
An endangered status on a particular animal species is categorised by the International Union for Conversation of Nature (IUCN) Red List. Although it has been labelled as a list, the IUCN Red List is a system assessing the global conversation status of species that includes Data Deficient (DD) species, which require more data and assessment before their status may be determined. Click on the link to check out the list of species categorised as Extinct (EX), Extinct in the Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near-Threatened (NT) and Least Concern (LC) and the criteria for Endangered (EN).
Will humans become extinct?
Human extinction could be the result of natural causes or anthropogenic causes i.e. result of human action. The likelihood of human extinction in the near future by wholly natural scenarios such as meteorite impacts or large-scale volcanism, is generally considered to be quite low. Anthropogenic extinction can be caused by many possible scenarios such as:
— Human Global Nuclear Annihilation
— Biological Warfare or the release of a pandemic-causing agent
— Dysgenics
— Overpopulation
— Ecological collapse
— Climate Change
Emerging technologies bringing about new extinction scenarios such as:
— Advanced Artificial Intelligence
— Biotechnology
— Self-replicating Nanobots
The prospect of anthropogenic human extinction within the next 100 years is debatable.
I’ll delve into the possible risks of human extinction in another post.
Which languages will go extinct?
https://en.wikipedia.org/wiki/Endangered_language
An endangered / moribund language is a language that is at risk of falling out of use as its speakers die out or shift to speaking another language. Language loss occurs when the language has no more native speakers which then becomes a “dead language”. If no one can speak the language at all, it becomes an “extinct language”. A dead language may still be studied through recordings or writings, but it’s technically dead or extinct unless fluent speakers of that language still remain. Although languages have always become extinct throughout human history, they are currently dying at an accelerated rate because of globalisation, neocolonialism and linguicide (language killing). Language shift most commonly occurs when speakers switch to a language associated with social or economic power or spoken more widely, which ultimately results in language death. The general consensus is that there are between 6,000 and 7,000 languages currently spoken and that between 50% and 90% of them will become extinct by the year 2100. The 20 most common languages, each with more than 50 million speakers, are spoken by 50% of the world’s population, but more languages are spoken by fewer than 10,000 people.
(1) Potential endangerment = This is when a language faces strong external pressure, but there are still communities of speakers who pass the language to their children.
(2) Endangerment = When only a few speakers of a language are left and children are mostly not learning the language.
(3) Seriously Endangered = When a language is unlikely to survive another generation and will soon be extinct.
(4) Moribund
(5) Extinction
Not only spoken languages are endangered, but also sign languages are also endangered such as AVSL (Alipur Village Sign Language) of India, Adamorobe Sign of Language of Ghana, Ban Khor Sign Language of Thailand, and Plains Indian Sign Language. Many sign languages are used by small communities but they can become endangered due changes in their environment such as contact with a larger sign language or dispersal of deaf community.
According to the Cambridge Handbook of Endangered Languages, there are 4 main types of causes of language endangerment:
(A) Causes that put populations who currently speak the languages in physical danger such as:
1. Natural Disasters, Famine, Disease — Depending on their severity, it could potentially wipe out an entire population of native language speakers whom have the capability of endangering a language e.g. The 2004 Indian Ocean earthquake and tsunami severely affected people of the Andaman Islands
2. War and Genocide — Languages of the indigenous population of Tasmania were wiped out by colonists. Many extinct and endangered languages of the Americas where indigenous people were subjected to genocidal violence. e.g. Miskito language in Nicaragua and the Mayan languages of Guatemala have been affected by civil war.
(B) Causes which prevent or discourage speakers from using a language such as:
1. Political repression — When nation-states work to promote a single national culture which limit opportunities for or prohibit using minority languages in the public sphere, schools, media, and elsewhere. Sometimes ethnic groups are forcibly resettled, or children are removed to be schooled away from home, or otherwise have their chances of cultural and linguistic continuity disrupted. This has happened for many Native American and Australian languages, European and Asian minority languages such as Breton, Occitan or Alsatian in France and Kurdish in Turkey.
2. Cultural / Political / Economic marginalisation / hegemony — Cultural imperialism occurs when political and economic power closely attaches to a certain language and culture to build a strong incentive for individuals to abandon their language (on behalf of themselves and their children) in favour of a more prestigious language. e.g. Assimilatory education. This happens when indigenous populations, in order to achieve a higher social status, have better chance in earning employment or are forced to it in school. They adopt the cultural and linguistic traits of people who came to dominate them through colonisation, conquest, or innovation. e.g. Welsh, Scottish Gaelic, Scots in Great Britian, Ainu language in Japan and Chamarro language in Guam. Ever since the Indian government adopted Hindi as the official language of the union government, Hindi has dominated many languages in India. Other forms of cultural imperialism include religion and technology. Religious groups may hold the belief that use of a certain language is immoral or require its followers to speak one language that is the approved language of the religion. Cultural hegemony often arises from increasing contact with a larger and more influential language community through better communications compered with relative isolation of past centuries.
3. Urbanisation — This involves the movement of people unto urban areas which forces people to learn the language of their new environment. Eventually, later generations will lose the ability to speak their native language, leading to endangerment. Once urbanisation takes place, new families who live there will be under pressure the speak the lingua franca of the city.
4. Intermarriage — This pressures one person or the other to speak one language to each other, which may lead to their children only only speaking the more common language spoken between the married couple.
https://en.wikipedia.org/wiki/Extinct_language
Extinct languages are languages that no longer has any speakers, especially if the language has no living descendants. This is not to be confused with “dead languages” that are no longer the native language of any community, even if it is still in use, like Latin. Languages that currently have living native speakers are sometimes called modern languages. In the modern period, languages have typically become extinct as a result of the process of cultural assimilation leading to language shift, and the gradual abandonment of a native language in favour of a foreign lingua franca, largely those of European countries. As of 2000s, about 7,000 natively spoken languages existed worldwide. Most of these are minor languages are in danger extinction. 1 estimate published in 2004 expected that about 90% of the currently spoken languages will be extinct by 2050. The transition from a spoken to an extinct language occurs when a language undergoes language death by directly replaced by a different one. e.g. Many Native American languages were replaced by English, French, Portuguese, Spanish or Dutch as a result of colonisation. However a historical language remains in use as a literary or liturgical language long after it ceases to be spoken natively, known as ‘dead languages’ or more typically ‘classical languages’. A prominent Western example is Latin, but comparable cases are found throughout world history due to the universal tendency to retain an historical stage of a language as liturgical language. Historical languages with living descendants that underwent significant language change are considered ‘extinct’, esp. in cases where they didn’t leave a corpus of literature or liturgy that remained in widespread use. This is the case with Old English or Old High German relative to their contemporary descendants, English and German respectively.
Here is a list of languages that have reported to be extinct this century:
— On February, 2016, Alban Michael from British Columbia, Canada was the last speaker of the Nuchatlakt dialect of Nuu-chah-nulth, which is a Wakashan language.
— On February 4, 2014, Hazel Sampson from Washington. USA: northeast Olympic Peninsula, Port Angeles was the last speaker of Klallam (Na’klallam, S’klallam) which is a Salishan language.
— On June 5, 2014, Grizelda Kristina from Latvia: west of Kolasrags, 12 coastal villages; Riga area dispersed, was the last speaker of Livonian (Liv. Livô kel), which is a Uralic language.
— On October 2, 2012, Bobby Hogg from Northern Scotland, UK was the last speaker of the Cromarty dialect of Scots (Black Isle dialect), which is a Germanic language.
— On October 24, 2010, Pan Jin-yu from Taiwan: West coast area, east of Tayal, Cholan area, Houli, Fengyuan, Tantzu, Taichung, Tungshih, was the last speaker of Pazeh (Kulon-pazeh), one of the Formosan languages.
— On August 10, 2010, William Rozario from southern India: Vypeen Island in the city of Cochin (Kochi) in Kerala, was the last speaker of Cochin Indo-Portugese Creole (Vypin Indo-Portuguese), which is a Portuguese-based Creole language.
— On January 26, 2010, Boa Sr. from the Andaman Islands, India: east central coast of North Andaman Island, North Reef Island, was the last speaker of Aka-Bo (Bo), which is an Andamanese language.
— On December 2009, Willie Seaton from Australia: Northeast Queensland, Herberton south to Herbert river headwaters, to Cashmere, at Ravenshoe, Millaa Millaa and Woodleigh, east to Tully Falls, was the last speaker of Nyawaygi, which is a Pama-Nyungan language.
— On November 2009, Boro from the Andaman Islands, India, northeast and north central costs of North Andaman Islands, Smith Island, was the last speaker of Aka-Kora (Kora), which is another Andamanese language.
— On January 21, 2008, Marie Smith Jones from Alaska, USA: Copper river mouth, was the last speaker of Eyak (I-ya-q), which is a Na-Dene language.
— In 2005, Lucille Roubedeaux from Oklahoma, USA, was the last speaker of Osage, which is a Siouan language.
— In 2003, Marja Sergine from Kola Peninsula, Russia: Murmanskaya Oblast’. southwest Kola peninsula, was the last speaker of Akkala Sami (Ahkkil. Babino, Babinsk), which is a Uralic language.
— On May 2002, Big Bill Neidljie from Northern Territory, Australia: Oenpelli, was the last speaker of the Gaagudja (Abdedal, Abiddul, Gaagudju, Kakadu, Kakaktu, Kakdju, Kakdjuan), which is one of the Arnhem Land languages.
— In 2000, Maurice Tabi from Pentacoast Island, Vanuatu, was the last speaker of Sowa, which is a Malayo-Polynesian language.
What resources will we eventually run out of?
Fossil fuels like coal, oil and gas are finite. As we continue to consume them, one day we will eventually run out of global resources. In 1956, M. King Hubbert published his hypothesis that for any given region, a fossil fuel production curve would follow a bell-shaped curve, also known as the Hubbert Curve which illustrates Hubbert’s Peak Theory. The graph illustrates an initial increase in resource production like oil following its discovery and improved extraction methods, approaching a peak, then ultimately declining as resources become depleted. His prediction that the US would peak in oil production in 1970 was confirmed, although it peaked 17% higher than he projected. Since peaking, its pathway hasn’t followed the bell-shaped curve he predicted.
This is shown in the chart below with Hubert’s hypothesised peak shown alongside the actual US production data reported by the Energy Information Administration (EIA); both curves are measured in barrels produced per year.
The quantity of fossil fuels we abandon is referred to as “unburnable Carbon”. According to a Carbon Tracker study, there is significant potential for unburnable carbon to result in major economic losses. If capital investment in carbon-emitting infrastructure continues at current rates, an estimated $US6.74 trillion would be wasted over the next decade in the development of reserves that will eventually be unburnable, which is defined as “stranded assets”. So whilst many governments, economists, energy companies and refineries worry about the possibility of fossil fuels running out, instead it’s expected that we’ll have to leave between 65-80% of our current known reserves untouched if we aim to keep our average global temperature rise below the 2 degrees Celsius global target.
What are the long term effects of global warming and climate change?
Most discussion and research including that by the Intergovernmental Panel on Climate Change (IPCC) reports, focuses on the effects of global warming up to 2100, with only an outline of the effects beyond that year.
Firstly, meltwater from melting ice sheets and glacier retreat contributes to a rise in the future sea level. There are concerns about the stability of the West Antarctic Ice Sheet (WAIS). Although the timescale is uncertain, a qualitative WAIS change could occur within this millennium. As a worst case scenario, it may collapse within 300 years. Rapid sea-level rise i.e. greater than 1 metre every century is more likely to exacerbate from the WAIS than from the Greenland Ice Sheet. A 2015 study evaluated that assuming cumulative fossil fuel emissions of 10,000 gigatonnes of Carbon, the Antarctic Ice Sheet could melt completely over the following millennia. It would contribute 58 metres to global sea-level rise, and 30 metres within the first millennium. Greenland’s ice sheet contains enough freshwater as ice to raise the sea level worldwide by 7 metres (23 feet). By 2100, Greenland may become adequately warm to begin a virtual complete melt over more than a millennium. One study suggests it would take 3,000 years to completely melt the Greenland ice sheet, which was derived from the assumed levels of greenhouse gases over the duration of the experiment. As the Greenland ice sheet loses mass from calving of icebergs and melting of its ice, any such processes would accelerate the loss of the ice sheet.
Early work with simplified models suggested that global warming could cause a shutdown of the thermohaline circulation. But more sophisticated coupled ocean-atmosphere global climate models fail to replicate the same shutdown.
— There are suggestions of declining oxygen dissolving in the oceans called ocean anoxia. This effect was determined using a model run of 10,000 years, which if true, could have adverse consequences for aquatic life. Researched predicted “severe, long-term ocean oxygen depletion and massive expansion of ocean oxygen-minimum zones for scenarios with high emissions or high climate sensitivity. They found that climate feedbacks within the Earth system amplify the strength and duration of global warming, ocean heating and oxygen depletion. There would be decreased oxygen solubility from surface-layer warming, which accounts for most of the enhanced oxygen depletion in the upper 500m of the ocean. There may be possible weakening of ocean overturning and convection, which would lead to further oxygen depletion in our atmosphere and in our deep oceans.
— A 1996 study has discovered a global distribution of confirmed or inferred gas hydrate-bearing sediments. Extremely large deposits of methane clathrate have been discovered under sediments on the ocean floors, which is estimated to be 3000 - 11,000 Gigaton of Carbon. Moreover there may be about 400 Gigatons for sediments under permafrost regions. Methane Clathrate, or Methane Hydrate, is a form of water ice that contains methane within its crystal structure.
— Stabilising the global average temperature would require significant reductions in CO2 emissions and greenhouse gases such as Methane and Nitrous Oxide. The desired target would be reducing CO2 emissions by more than 80% relative to their peak level. Even if we reached this target successfully, global average temperature would still be at its highest level for centuries. As of 2016, CO2 emissions from burning fossil fuels had stopped increasing but greenhouse gases continue to accumulate in the atmosphere. It’s theorised that changing absorption patterns of the ocean and land surface may account for the continual rise in CO2 levels, which suggests they may have reached their limit of their ability to absorb CO2 .
— While the warm surface of the oceans have limited ability to absorb anthropogenic Carbon Dioxide, the coldest surface waters near the poles (covering 2-3% of ocean surfaces) can transfer significant amounts of Carbon Dioxide to deep-ocean reserves. Over a period of centuries, this process as well as the process of Calcium Carbonate absorption of Carbon Dioxide on land and in the oceans will remove 60 - 80^ of the excess Carbon Dioxide. When exposed to a near surface environment, igneous rock absorbs Carbon Dioxide through a steady weathering rate, but weathering increases in a warmer, higher rainfall climate, which accelerates this process. This geological weathering will absorb the remaining 20-40% anthropogenic Carbon Dioxide over the period of 10,000s — 100,000s of years.
But what I’m really worried about is Earth’s future.
— What will happen to it?
— Will it cease to exist eventually?
— If so, how?
The ground beneath you is moving as you read this. Earth’s surface is divided into tectonic plates and they carry the water and land above it. Thed motion of all tectonic plates are relative to each other. Because the plates rotating as well as moving, and the direction in which they move and our rotation is influenced by other plates around them, so there is no absolute vector that can be given for each plate. Therefore local vectors for the interaction between any 2 adjacent plates.
At the mid-ocean ridges, tectonic plates there move away from the spreading centres, collide with other plates forming either subduction zones (volcano arcs beside ocean trenches, where one of the plates slides underneath the other. Therefore much of the Pacific Ocean margin or collision zones where mountains such as the Himalayas form as 1 plate crumples while overriding the other. Furthermore, 2 plates can slide alongside each other without forming mountains or volcanoes which create earthquakes e.g. San Andreas Fault in California, USA
Tectonic plates move because they are floating on top of a liquid called Mantle. The mantle itself moves due to convection currents which refer to rising hot rock transferring heat to the top of the cycle cooling it down and then fall down towards the Earth’s core. This creates vast swirls of moving liquid rock under Earth’s crust, which jostles the plates of crust on top. Nobody really knows the full details of the convection cells because they’re hard to study due to their immense depth. Earthquakes are probably less about changes in the underlying convection, and more like sudden responses to strain. Drastic movements of plate tectonics occur over periods of 100s of 1000s to millions of years, but it doesn’t all proceed evenly. Sections of tectonic plates adhere against each other which builds up tension and frictional energy over time. When the tectonic plates finally give way, all this built frictional energy is released and transformed into kinetic, heat and vibrational energies which gives you that sudden jolt of a few tens of feet. This shock is quite brief, in the plate tectonic scheme of things, but it’s enough to topple skyscrapers and houses.
Convection cells themselves change over time making it a chaotic system. This may be related to the millions-of-years scale of pole flips. Earthquakes can occur more locally on much smaller scales. Every tectonic plate change direction over time, whilst jostling about like floatable toys in a bathtub.
https://en.wikipedia.org/wiki/Pangaea_Ultima
However will this continuous unpredictable movement of tectonic plates one day reunite the land masses to form another Pangaea supercontinent?
If predictions is consistent with the supercontinent cycle, a future supercontinent called Pangaea Ultima (Pangaea Proxima, Neopangaea or Pangaea II) could occur within the next 250 million years. A rough approximation illustrated below:
(1) Subduction at the western Atlantic, east of the Americas
(2) Subduction of the Atlantic mid-ocean ridge.
(3) Further subduction destroying the Atlantic and Indian basic
(4) Atlantic and Indian Oceans will close
(5) Pulls the Americas back together with Africa and Europe.
As with most supercontinents, the interior of Pangaea Proxima would probably become a semi-arid desert prone to extreme temperatures.
According to the Pangaea Ultima hypothesis, the Atlantic and Indian Oceans will continue to get wider until new subduction zones bring the continents back together, forming a future Pangaea. Most continents and microcontinents are predicted to collide with Eurasia. Around 50 million years from now:
1. North America is predicted to shift slightly west and Eurasia would shift to
the east, and possibly even to the south.
2. This would bring Great Britain closer to the North Polee and Siberia
southward towards warm subtropical latitudes.
3. Africa is predicted to collide with Europe and Arabia.
4. This will close the Mediterranean Sea, which completely closes the
Tethys Ocean (or Neotethys) and the Red Sea.
5. A long mountain range would then extend from Iberia, across Southern
Europe called the Mediterranean Mountain Range into Asia.
6. Some are predicted to have peaks higher than Mount Everest.
7. Similar Australia is predicted to beach itself past the doorstep of
Southeast Africa.
8. This will cause the islands to be compressed inland to form another
potential mountain range.
9. Meanwhile, Southern and Baja California are predicted to have already
collided with Alaska with new mountain ranged formed between them.
Around 150 million years from now:
10. The Atlantic Ocean is predicted to stop widening and begin to shrink because some of the Mid-Atlantic Ridge will have been sub ducted.
11. Therefore a mid-ocean ridge between South America and Africa will probably subduct first.
12. This will narrow the Atlantic Ocean as a result of subduction beneath the North & South American continents.
13. The Indian Ocean is also predicted to shrink due to northward subduction of oceanic crust into the Central Indian trench.
14. Antaractica is expected to shift upwards, which then collides with Madagascar and Australia.
15. This will enclose a remnant of the Indian Ocean (called the Indo-Atlantic Ocean).
16. When the last of the MId-Atlantic Ridge is sub ducted beneath the Americas, the Atlantic Ocean is predicted to close rapidly.
Around 250 million years from now:
17. The Atlantic is predicted to have closed.
18. North America is predicted to have already collided with Africa, but in a more southerly position than where it drifted.
19. South America is predicted to be wrapped around the southern tip of Africa.
20. This will enclose the Indo-Atlantic Ocean.
21. The Pacific Ocean will have grown wider, encircling half of Earth’s surface.
According to paleogeologist Ronald Blakey, in the next 15 to 100 million years tectonic development will be fairly settled and predictable without a formation of a supercontinent. Beyond that, there is caution for the geologic record to be full of unexpected shifts in tectonic activity that make further projections quite speculative. You can check out animations of future tectonic movements by clicking on the link below:
https://www.youtube.com/watch?v=uLahVJNnoZ4
https://en.wikipedia.org/wiki/Andromeda–Milky_Way_collision
https://en.wikipedia.org/wiki/Andromeda_Galaxy
According to Vsauce's video “What will I miss out on?” it's estimated in about 3.75 billion years, the Andromeda galaxy is projected to collide with the Milky Way galaxy. At first impact, it will merge marrying the 2 galaxies together to form a giant elliptical galaxy or a large disc galaxy called Milkdromeda. With an apparent magnitude of 3.4, the Andromeda Galaxy is among the brightest of the Messier objects which makes it visible to the naked human eye on moonless nights, even when viewed from areas with moderate light pollution.
The chance of even 2 stars from each galaxy colliding is negligible because of the huge distances between the stars. e.g. The nearest star to our Sun is Proxima Centauri, which is about 4.2 light years (4.0 x 10^13, 2.5 x 10^13 miles) or 30 million solar diameters away. If the Sun were the size of a ping-pong ball, Proxima Centauri would be a pea about 1,100 km (680 miles) away, and the Milky Way would be about 30 million km (19 million miles) wide. Although stars are commonly situated near the centre of each galaxy, the average distance between stars is still 160 billion km (100 billion miles). Thus it’s extremely unlikely that any 2 stars from the merging galaxies would collide, so it’s safe to say our solar system isn’t in danger but our future night skies would look different and spectacular to the human eye.
The Milky Way and Andromeda galaxies each contain a central Supermassive Black Hole (SMBH) called Sagittarius A*(ca. 3.6 x 10^6 Mo) and an unnamed object within the P2 concentration of Andromeda’s Nucleus (1.2 x 10^8 Mo) respectively. These black holes will converge to the centre of the newly formed galaxy over a period that may take millions years to complete, due to a process called dynamical friction. As these 2 SMBHs move relative to the surrounding cloud of much less massive stars, gravitational interactions will lead to a net transfer of orbital energy from the SMBHs to the stars. This will cause the stars to be slingshotted into higher-radius orbits and the SMBHs will sink towards the galactic core. When the SMBHs come within 1 light-year of one another, they will begin to emit gravitational waves which will radiate further orbital energy until they merge completely. Gas taken up by the combined black hole could create a luminous quasar or on an active galactic nucleus, which would release as much energy as 100 million supernova explosions. According to simulations, the Sun might be brought near the centre of the combined galaxy, potentially approaching near one of the black holes before being ejected entirely out of the galaxy. Others predict the Sun might approach or be pulled by one of the black holes and then be torn apart by its gravity. But we will never know if those predictions will come true until billions of years has elapsed.
Click on this video to see a predicted simulation of the formation of Milkdromeda:
https://www.youtube.com/watch?v=qnYCpQyRp-4
- What’s the fate of our solar system?
- Will any new moons arrive at our solar system or any current moons leave their orbits around the planets?
As you’re reading this, the Moon continues to move outward picking up angular momentum from Earth thanks to tidal interactions. However this slows Earth’s rotation and eventually billions of years from now, Earth will tidally lock to the Moon. Other tidal effects relating to the 2 bodies against the Sun will dominate that gradually leverage the angular momentum of Earth and Moon together to push the pair together outward from the Sun, while the Moon reverses and starts to spiral in toward Earth again. Eventually, the Moon comes within Roche’s Limit and is broken up tidally. According to NASA, our moon is slowly moving away from Earth by about 4 cm (1.5 inches) every year. Therefore in the very distant future, we will have seen our last solar eclipse because the apparent size of the moon in Earth’s sky will be too small to completely cover the Sun. Over time, the amount and frequency of total solar eclipses will decrease and in about 600 million years from now, Earth will experience the beauty and drama of a total solar eclipse for the last time.
Will any of our planets change or are in jeopardy of collision compared to today?
Saturn is the only known ringed planet within the rings believed to be as old as the solar system ~ 100 million years. Examination of ring observations and data unconstrained by conventional chronology indicates that the actually lifetime of Saturn’s rings may be of the order of 10,000 years. This prediction satisfies the biblical Creation / Fall / Flood model.
A new 2017 study suggested Saturn’s rings may disappear in about 1 billion years. This prediction was made by data collected from the Cassini spacecraft via its Radio and Plasma Wave System (RPWS) used by a team of researchers led by William Farrell from NASA’s Goddard Space Flight Centre in Maryland. It’s known Saturn’s rings are gradually losing their material due to the presence of plasma, hence negatively charged electrons, created by a photolytic process caused by the Sun’s light rays. Because this process is “passive” compared to meteor impacts, it suggests that the rings will survive much longer than previously thought. Cassini is performing a series of 22 dives between Saturn and its rings, the closest a spacecraft has ever been to, to collect and transmit as much invaluable data as possible to validate the date of Saturn’s rings.
- How would the presence of trillions of stars affect the orbital paths of our solar system, warp the space-time continuum by their respective gravitational pulls?
Although the formation of Milkdromeda could result in ejection of the Solar System, but it’s considered unlikely to have any adverse effect on the Sun or its planets.
- Would it affect the surface temperature of Earth which would be catastrophic under many circumstances?
- Will humans be able to conduct interstellar voyages across the vastness of space to exoplanets similar to Earth?
https://en.wikipedia.org/wiki/Interstellar_travel
Optimists adamantly predict it’s possible manned missions around 50 - 100 years from now at relativistic speeds (0.97c = 97% of the speed of life = Warp 4) - that’s if. Interstellar travel is a term used for ‘hypothetical crewed or unscrewed travel between stars or planetary systems. Interstellar travel will be much difficult than interplanetary spaceflight. The distances between the planets in our Solar System are less than 30 AU (Astronomical Units) whereas the distance between stars are typically 100,000s of AU, and usually expressed in light-years (ly). The nearest star to the solar system, Alpha Centauri, is about 4.3 light years away. Because the vastness of those distances, interstellar travel would require a large proportion of the speed of the light. Even at the speed of the light, voyages would last quite a long time around centuries to millennia or longer. The speeds required for interstellar travel in a human lifetime far exceed what current methods of spacecraft propulsion can provide. Even with hypothetically perfectly efficient (100%) propulsion systems, the kinetic energy corresponding to those speeds is enormous by today’s standards of energy. Moreover, collisions by the spacecraft with cosmic dust and gas can produce dangerous effects both to spacecraft and the passengers inside.
In order to deal with these challenges, strategies ranging from giant arks carrying entire societies and ecosystems, to microscopic space probes. Given spacecraft the required enormous speeds require powerful spacecraft propulsion systems including nuclear propulsion, beam-powered propulsion, and methods based on speculative physics.
For both crewed and unscrewed interstellar travel, considerable technological and economical challenges need to be considered. Most interstellar travel concepts require a developed space logistics system capable of moving millions of tons to a construction / operating location, and most would require gigawatt-scale power for construction or power such as Star Wisp or Light Sail type concepts seen in Star Wars. Such a system would need to grow organically if space-based solar power becomes a significant component of Earth’s energy mix. Consumer demand for a multi-terawatt system would automatically create the necessary multi-million ton / year logistical system. I’ll delve into the challenges, proposals and details of interstellar travel in another post.
How and when will the Sun die?
https://en.wikipedia.org/wiki/Hertzsprung–Russell_diagram
The Hertzsprung-Russell Diagram, created by Ejnar Hertzsprung and Henry Norris Russell in 1910, is a scatterplot of stars displaying the relationship between the stars’ absolute magnitudes or luminosities Vs their stellar classifications or effective temperatures. The graph plots each star measuring the star’s brightness against its temperature (colour).
The sun will move off of the “main sequence” on the Hertzsprung-Russel (HR) diagram in about 4 or 5 billions years, but this isn’t the “death of the sun”. The next phase is the Red Giant phase, which is expected to last about 1 billion years. In this phase, the sun’s core is made of Helium, which is the product of nuclear burning of Hydrogen and the result of gravitational “settling”. Nuclear burning will continue in a thin Hydrogen shell around the core. Given the mass of the sun, the electrons in the Helium core will degenerate as the thermal temperature will be very small compared to the Fermi temperature. An increasing thermal temperature and a degenerating core are suitable conditions for Helium nuclear burning in the core to start. This will lead to an explosive event called a “Helium Flash” which is of insignificant time compared to time scales like a billion years.
After the “Helium Flash”, the sun will re-equilibrate onto the horizontal branch (HB) of the HR diagram. There it will undergo core Helium burning and shell Hydrogen burning. Once core Helium burning is exhausted, the core will contract and the sun will climb the asymptotic giant branch (AGB) on the HR diagram. The energy source during this phase is mainly shell Helium burning outside of a Carbon core.
After the AGB phase, pulsations and winds will drive the star into a “planetary nebula” phase. What remains after this is a white dwarf surrounded by the nebula. This is the final stage for the Sun. After that no more fusion will occur. The sun will remain a white dwarf and begin cooling down over time until the inevitable end of its life. Ordering of magnitude would mean the main sequence lifetime is “the lifetime” of the star, since the rest of the lifetime takes about 10% of that time. Therefore, the sun will be a white dwarf in 5 - 6 billion years.
The Sun generates energy from thermonuclear fusion of Hydrogen into Helium, which situates in the Sun’s core using the proton-proton chain reaction process. Because there’s no convection in the solar core, the Helium concentration accumulates without being distributed throughout its volume. The temperature at the Sun’s core isn’t adequately hot for nuclear fusion of Helium atoms through the triple-alpha process to occur, so these atoms don’t contribute to the net energy generation required to maintain hydrostatic equilibrium of the Sun. Presently, nearly half of the Hydrogen at the core has been consumed, with the remaining atoms consisting primarily of Helium. As the number of Hydrogen atoms per unit mass decreases, so too does their energy output provided through nuclear fusion. This leads to a decrease in pressure support, which causes contraction of the core until the increased density and temperature brings the core pressure into equilibrium with the layers above. The higher temperature causes the remaining Hydrogen to undergo fusion at a more rapid rate, thereby generating the energy needed to maintain the equilibrium. This process has demonstrated a steady increase in the energy output of the Sun. When the Sun became a main sequence star, it radiated only 70% of the current luminosity. Its luminosity has increased linearly to the present day, rising by 1% every 110 million years. In 3 billion years time, the Sun is predicted to be 33% more luminous after this linear extrapolation. When Hydrogen fuel at the core will be exhausted in 5 billion years, the Sun will be 67% more luminous than present. Thereafter as you read this, the Sun will continue to burn Hydrogen in a shell surrounding its core, until the luminosity reaches 121% above the present value. This will mark the end of the Sun’s main sequence lifetime, and thereafter it will pass through the sub giant stage and evolve into a red giant. By this time the collision of the Milky Way and Andromeda galaxies would already be underway.
The drag from the solar atmosphere may cause the orbit of the Moon to decay. Once the Moon’s orbit closes to a distance of 18.470 km (11,480 mi), it will cross the Earth’s Roche Limit. This means that tidal interaction with the Earth would decimate the Moon to become a ring system. Most of the orbiting ring will then decay and the debris will impact Earth. Hence, even if Earth survives the Sun’s Red Giant phase, Earth may remain moonless. The ablation and vaporisation caused by its fall on a decaying trajectory towards the Sun may wipe out Earth’s crust and mantle, revealing its core. The core will finally be destroyed after at most 200 years. Following this event, Earth’s sole legacy will be a minute increase (0.01%) of the solar metallicity.
After the Red Giant stage, Carbon will fuse Helium to the Sun’s core causing it to collapse again, evolving into a compact white dwarf star after ejecting its outer atmosphere as a planetary nebula. In 50 billion years, if the Earth and Moon miraculously aren’t engulfed by the Sun, they will become tide locked, with each showing only 1 face to the other. Thereafter, the tidal action of the Sun will extract angular momentum from the system, causing the lunar orbit to decay and the Earth’s spin to accelerate. In about 65 billion years, it’s estimate that the Moon may end up colliding with Earth, assuming they aren’t destroyed by the red giant Sun, due to the remaining energy of the Earth-Moon system being sapped by the remnant Sun, causing the Moon to slowly move inwards towards Earth. Over time intervals of around 30 trillion years, the Sun will undergo a close encounter with another star. As a consequence, orbits of their planets can be disrupted potentially ejecting them from that system entirely. If Earth isn’t destroyed by the expanding red giant Sun in 7.6 billion years and not ejected from its orbit by a stellar encounter, its ultimate fate will be that it collides with the black dwarf Sun due to the decay of its orbit via gravitational radiation in 1020 (100 quintillion years).
https://en.wikipedia.org/wiki/Future_of_Earth
What’s the future of Earth like?
Over time intervals of 100s of millions of years, random celestial events pose a global risk to the biosphere, resulting in mass extinction. These events include impacts by comets or asteroids, a supernova, within a 100 light-year radius of the Sun; known as a near-Earth supernova. If we disregard the long-term effects of global warming, then the Milankovitch Theory predicts that the planet will continue to undergo glacial periods at least until the Quaternary glaciation comes to an end. These periods are caused by variations in eccentricity, axial tilt, and precession of Earth’s orbit. Plate tectonics will result in a supercontinent in 250-350 million years time as part of the supercontinent cycle. Some time in the next 1.5 - 4.5 billion years, the axial tilt of the Earth may begin to undergo chaotic variations with changes of up to 90 degrees.
The luminosity of the Sun will steadily increase, resulting in a rise in the solar radiation reaching Earth. This will result in a higher rate of weathering of Silicate minerals, which causes a decrease in the level of Carbon Dioxide in the atmosphere. In about 600 million years from today, the level of Carbon Dioxide will fall below the critical threshold in order to sustain C3 Carbon fixation photosynthesis used by trees ~ about 50 parts per million. Some plants use the C4 Carbon fixation method which allows them to maintain CO2 concentrations as low as 10 parts per million. Thus plants using C4 photosynthesis would survive for at least 800 million years and as long as 1.2 billion years from now. Thereafter, rising temperatures will make the biosphere unsustainable. Currently, C4 plants represent about 5% of Earth’s plant biomass and 1% of its known plant species. e.g. About 50% of all grass species (Poaceae) and use the C4 photosynthetic pathway, as do many species in the Amaranthacaea herbaceous family.When Carbon Dioxide levels fall to the limit where photosynthesis is unsustainable, the proportion of Carbon Dioxide in the atmosphere is expected to oscillate up and down. This will allow land vegetation to flourish each time the level of Carbon Dioxide rises due to tectonic activity and animal life.
However the long-term trend is for plant life to die off altogether as most of the remaining atmospheric Carbon becomes sequestered in the Earth. Some microbes are capable of photosynthesis at concentrations of Carbon Dioxide of a few parts per million, so these life forms may disappear only due to rising temperatures and loss of the biosphere. Plants and animals could survive longer by evolving other strategies like requiring less Carbon Dioxide for photosynthetic processes. These organisms will become carnivorous, adapt to desiccation, or associate with fungi. These adaptations are likely to appear near the beginning of the moist greenhouse.
The extinction of plants will be the demise of almost all animal life including humans, since plants are the base of the food chain on Earth. The main causes include the eventual loss of oxygen and ozone due to the respiration of animals, chemical reactions in the atmosphere and volcanic eruptions. This will result in less attenuation of DNA-damaging UV radiation and fall of the animal kingdom. The first animals to disappear would most likely be large mammals, followed by small mammals, then birds, amphibians and large fish, reptiles and small fish, and finally invertebrates. Prior to this extinction, life is expected to concentrate at refugia of lower temperatures such as places of higher altitudes where less land surface area is available, thus restricting population sizes. Smaller animals have a higher survival rate than larger animals because their oxygen requirements aren’t as high. Meanwhile, birds would fare better than mammals due to their ability to travel long distances scavenging for places of colder temperatures. In there work The Life and Death of Planet Earth, authors Peter D. Ward and Donald Brownlee argued that some animal lifeforms may continue even after most of Earth’s plant life has disappeared. They used fossil evidence from the Burgess Shale in British Columbia, Canada, to determine the climate of the Cambrian Explosion. They then used this data to predict the climate of the future. As global temperatures rise caused by a warming Sun and oxygen levels decline, this will result in the final extinction of animal life. Initially, they expect some insects, lizards, birds and small mammals to persist, along with some aquatic life. However, without oxygen replenishment by plant life, they believe that animals would probably become extinct from asphyxiation within a few million years. Even if sufficient oxygen were to remain in Earth’s atmosphere thanks to persisting forms of photosynthesis, the steady rise in global temperatures would result in a gradual loss of biodiversity.
As temperatures continue increasing, the last animal life will be driven back toward Earth’s geographic poles and dig themselves underground homes. Their primary activity occurs during the polar night, aestivates during the polar day due to the intense heat. Much of Earth’s surface would become a barren desert bigger than the Sahara Desert, thus life would primarily thrive in the oceans. Nevertheless, there is decreased amounts of organic matter arriving at the oceans from land as well as lack of oxygen in the water. The disappearance of life in the oceans would follow a similar decline to how life on Earth’s land surface disappeared. The process would begin with the loss of freshwater species and terminate with invertebrates, especially those dependent on living plants such as termites or those living near hydrothermal vents such as worms of the genus Riftia. This will cause the extinction of multi-cellular lifeforms in about 800 million years, and eukaryotes in 1.3 billion years. What remains are the prokaryotes.
About 1 billion years from today, about 27% of the modern ocean will be subducted into Earth’s mantle. If this process continues uninterrupted, it would reach an equilibrium state where 65% of the current surface reservoir would remain at the surface. The solar luminosity will increase by 10% than its current value. This will increase the average global surface temperature to 320 K (47 degrees C, 116 degrees F). This will cause the atmosphere to become a moist greenhouse, resulting in a runaway evaporation of the oceans. At this point, models of the Earth’s future environment predict the stratosphere will have increases in water levels. These water molecules will disintegrate through photodissociation by solar UV radiation, which will allow Hydrogen to escape Earth’s atmosphere. The net result will be a loss of the world’s seawater by about 1.1 billion years from the present day. There are 2 variations of the future warming feedback:
(1) The “moist greenhouse” — Where water vapour dominates the troposphere while water vapour starts to accumulate in the stratosphere if the oceans evaporate rapidly.
(2) The “runaway greenhouse” — Where water vapour dominates the atmosphere if the oceans evaporate steadily.
Earth will undergo rapid warming, sending its surface temperature to over 900 degrees C or 1650 degrees F. The atmosphere will be overwhelmed by water vapour, causing its entire surface to melt and killing all life in about 3 billion years. During this ocean-free era, surface reservoirs will continue to appear as water is gradually released from the deep crust and mantle. It’s estimated the amount of water beneath Earth’s surface is equivalent to several times that are currently present in today’s oceans. Some water may be retained at the poles and even with the occasional drizzle, Earth would still be a barren desert with large dunefields covering the equator, and a few salt flats on what was once the ocean floor, similar to the ones found in the Atacama Desert in Chile. With no water to lubricate the plate tectonics, they would stop. The first visible signs of consequential geological activity would be volcanoes located above mantle hotspots. In these arid conditions, Earth would retain several microbial and multi-cellular lifeforms like halophiles. However, the increasingly extreme conditions will lead to extinction of the prokaryotes between 1.6 and 2.8 billion years from now. The last remaining prokaryotes will most likely live in residual ponds of water at high altitudes and heights or in caverns with trapped ice. However, underground life has the potential to last longer depending on the level of tectonic activity. if volcanic eruptions release Carbon Dioxide steadily, this would cause the atmosphere to enter “super greenhouse” state like that of on planet Venus. But most of the carbonates would remain securely buried until the Sun became a red giant and its increased luminosity heated the rock to the point of releasing this Carbon Dioxide.
The loss of Earth’s oceans may be delayed for another 2 billion years if the total atmospheric pressure were to decrease. A lower atmospheric pressure would reduce the greenhouse effect, thereby decreasing the surface temperature. This would occur if natural processes removed Nitrogen from the atmosphere. Studies of organic sediments concluded that at least 100 KPa (kilopascals) or 0.99 atm of Nitrogen have already been removed from the atmosphere over the past 4 billion years. This will effectively double the current atmospheric pressure if it were to be released. This rate of removal would be sufficient to counter the effects of increasing solar luminosity for the next 2 billion years. 2.8 billion years from now, Earth’s surface temperature will reach 422 K (149 degrees C, 300 degrees F). At this point, any remaining life will be extinguished due to the extreme conditions. If Earth loses its surface water, it will remain that way until the Sun becomes a red giant. But if this scenario doesn’t become true, then in about 3 -4 billion years, the amount of water vapour in the lower atmosphere will increase to 40%. This leads to the commendation of a moist greenhouse effect once the Sun's luminosity reaches 35 - 40% more than its current value. A “runaway greenhouse” effect will ensue, which increases the temperature of the atmosphere and the Earth’s surface to around 1600 K (1330 degrees C, 2420 degrees F). This is enough to melt Earth’s surface. However, most of the atmosphere will be retained until the Sun has entered the Red Giant stage. Following the extinction of life, Earths biosignatures will also disappear to be replace by signatures caused by non-biological processes.
The Holocene extinction refers to the widespread, ongoing mass extinction of other species during the present geological epoch caused by humans since the 1950s. It has been described as a biotic crisis, with an estimated 10% of the total species lost as of 2007. At current rates, about 30% of species are at risk of extinction in the next 100 years. Because there is a large human population in the biosphere which dominates many of Earth’s ecosystems, it has caused habitat destruction, widespread distribution of invasive species, hunting and climate change. Presently, human activity has had a significant impact on the surface of the planet with more than 1/3 of the land surface been modified by human actions, and human use about 20% of global of primary production. The concentration of Carbon Dioxide in the our atmosphere has increased by close to 30% since the start of the Industrial Revolution. The consequences of a persistent biotic crisis have been predicted to last for at least 5 million years. This would result in decline in biodiversity and homogenisation of biotas, accompanied by a proliferation of opportunistic species such as pests and weeds. Novel species may also energy, particularly taxa prospering in human-dominated ecosystems. Their populations would rapidly diversify into many new species. Microbes are likely to benefit from the increase in nutrient-enriched environment niches. Nevertheless, no novel species of existing living vertebrates are likely to arise and food chains may be depleted.
Risks that humanity to itself include climate change, misuse of nanotechnology, nuclear holocaust, warfare with a programmed superintelligence, a genetically engineered disease, or a disaster caused by a physics experiment. Several natural events pose a doomsday threat, including a highly virulent disease, the impact of an asteroid or comet, runaway greenhouse effect, and resource depletion. There may be a possibility of an infestation of an extraterrestrial life form but the actual odds are these scenarios occurring are difficult to deduce. Should the human race become extinct, then the various features assembled by humanity will begin to decay. The largest structures have an estimated decay half-life of about 1,000 years. The last surviving structures would most likely be open pit mines, large landfills, major highways, wide canal cats, and earth-fill flank dams. A few massive stone monuments like the Pyramids of Giza Necropolis, or the sculptures at Mount Rushmore may still survive in some form after a million years.
As the Sun orbits the Milky Way, wandering stars may approach close enough to have a disruptive influence on the Solar System. Close stellar encounters would cause significant reduction in the perihelion distances of comets in the Oort cloud, which is a spherical region of icy bodies orbiting within half a light year of the Sun. Such an encounter would trigger a 40-fold increase in the number of comets reaching the inner Solar System. Impacts from these comets would trigger mass extinction of life on Earth. These disruptive encounters occur at an average of once every 45 million years. The average time for the Sun to collide with another star in the solar neighbourhood is about 3 x 10^13 years (30 trillion years), which is very unlikely given the estimated age of the Milky Way galaxy, at about 1.3 x 10^10 years (13 billion years). The energy release from the impact of an asteroid or comet with a diameter of 5-10 km (3.1 - 6.2 miles) or larger is enough to create a global environmental disaster and cause a statistically significant number of species extinctions. Among the deleterious effects resulting from this catastrophic event include clouds of fine dust ejecta blanketing the planet, which will decrease land temperatures by 15 degrees C or 27 degrees F within a week and halt photosynthesis for several months. The mean time between major impacts is estimated to be about 100 million years. During the last 540 million years, simulations have illustrated that such an impact rate is sufficient to cause 5 - 6 mass extinctions and 20 - 30 lower severity events. This matches the geologic record of significant extinctions during the Phanerozoic Eon. Such events are expected to occur in the future.
Within the Milky Way galaxy, supernova explosions occur on average once every 40 years. During the history of Earth, multiple such events have likely occurred within a 100 light tears. Cataclysmic explosions of stars within this distance would contaminate the planet with radioisotopes and impact the biosphere. Gamma Rays emitted by supernovas react with Nitrogen in the atmosphere to produce Nitrous Oxides, which would deplete the Ozone layer that protects the surface from UV (ultraviolet) radiation from the Sun. An increase in UV-B radiation of only 10-30% is sufficient to cause a significant impact on life such as phytoplankton which form the base of the oceanic food chain. A supernova explosion 26 light years from Earth will reduce the Ozone column density by 50%. On average, a supernova explosion occurs within 32 light years once every few 100 million years. This would deplete the Ozone layer lasting several centuries. Over the next 2 billion years, there will be about 20 supernova explosions and 1 gamma ray burst which will have a lasting impact on the planet’s biosphere.
The incremental effect of gravitational perturbations between the planets causes the inner Solar System as a whole to behave chaotically over long periods. However, this doesn’t significantly affect the stability of the Solar System over internals of a few million years or less, but over billions of years the orbits of the planets become unpredictable. Computer simulations of the Solar System’s evolution over the next 5 billion years suggest a less than 1% change of a collision occurring between Earth and either Mercury, Venus or Mars. During the same interval, the odds that Earth will be scattered our of the Solar System by a passing star are on the order of 1 in 100,000. Such a scenario would freeze our oceans solid within several million years. This would leave only a few pockets of liquid water about 14km (8.7 miles) underground. There is a remote chance that Earth will instead be captured by a passing binary star system, which will allow its biosphere to remain intact but odds of this happening are about 3 million to 1.
The gravitational perturbations of other planets in our Solar System combine to modify the orbit of the Earth and the orientation of the spin axis, which influences our planetary climate. Despite such interactions, simulations accurately demonstrate that overall, Earth’s orbit is likely to remain dynamically stable for billions of years into the future. This includes semimajor axis, eccentricity, and inclination.
— Glaciation: Historically, there have been cycles of ice ages in which glacial sheets periodically covered regions of higher latitudes of Earth’s continents. Ice ages may occur because of changes in ocean circulation and continentality induced by plate tectonics. The Milankovitch theory predicts that glacial periods occur during ice ages because of astronomical factors in combination with climate feedback mechanisms. The primary astronomical drivers are increased orbital eccentricity, lower axial tilt (obliquity), and alignment of summer solstice with the aphelion. Eccentricity changes over time cycles of about 100,000 and 400,000 years, ranging from less 0.01 up to 0.05. This is equivalent to a change of the semi-minor axis of the planet’s orbit from 99.95% of the semi-major axis of 99.88%, respectively. The Earth is passing through an ice age known as a Quaternary Glaciation, present in the Holocene interglacial period. This period is expected to end in about 25,000 years. However, the increased rate of Carbon Dioxide release into the atmosphere by humans may delay onset of the next glacial period until at least 50,000 - 13,000 years from now. On the other hand, a global warming period of finite duration (assuming fossil fuel use will cease by the year 2200) will probably impact the glacial period for about 5,000 years. Thus, a brief period of global warming induced through a few centuries worth of greenhouse gas emission would only have a limited impact in the long term.
— Obliquity: The tidal acceleration of the Moon slows the rotation rate of Earth and increases the distance between the Moon and the Earth. There is friction between the core and mantle and between the atmosphere and surface. These effects can dissipate the Earth’s rotational energy and when combined will increased the length of a day by more than 1.5 hours over the next 250 million years, and to increase the obliquity by about 1/2 of a degree. The distance between Earth and Moon will increase by about 1.5 Earth radii during the same period. Computer models show the presence of Moon stabilises Earth’s obliquity, which helps it avoid dramatic climate changes. This stability is achieved because the Moon increase the precession rate of the Earth’s spin axis, thereby avoiding resonances between the precession of the spin and the precession of Earth’s orbital plane i.e. Precession motion of the ecliptic. However, as the semi-major axis of the Moon’s orbit continues to increase, this stabilising effect will diminish. At some point, perturbation effects will cause chaotic variations in Earth’s obliquity, and the axial tilt may change by angles as high as 90 degrees from the plane of the orbit. This is expected to occur between 1.5 and 4.5 billion years from now. A high obliquity would result in dramatic climatic changes which would lead to destruction of Earth’s habitability. If Earth’s axial tilt exceeds 54 degrees, the yearly insulation at the equator will be less than that at the poles. Earth could remain at an obliquity of 60 to 90 degrees for periods as long as 10 million years.
— Geodynamics: Tectonics-based events will continue to occur well into the future and the surface will be steadily reshaped by tectonic uplift, extrusions, and erosion. Mount Vesuvius is expected to erupt about 40 times over the next 1000 years. During the same period, about 5 - 7 earthquakes of magnitude 8 or greater is expected to occur along the San Andreas Fault. Moreover, about 50 magnitude 9 events is predicted to occur worldwide. Mauna Loa is expected to experience about 200 eruptions over the next 1000 years, and the Old Faithful Geyser will likely cease to operate. The Niagara Falls will continue to retreat upstream, reaching Buffalo in about 30,000 - 50,000 years. In 10,000 years, the post-glacial rebound of the Baltic Sea will have increased in shallowness by about 90 m (300 ft) and The Hudson Bay will be shallower by 100m. After 100,000 years, the island of Hawaii will have shifted about 9km (5.6 mi) northwest. This means Earth may enter another glacial period by this time.
— Continental Drift: The theory of plate tectonics describes the movement of Earth’s continents across the surface at a rate of a few cm every year, which is expected to continue as you read this, leading to relocation and collision of the plates. Continental drift is facilitated by 2 factors: energy generation within Earth’s core and the presence of a hydrosphere. A loss of either factor will halt continental drift. Heat produced by radiogenic processes is sufficient to maintain mantle convection and plate subduction for at least the next 1.1 billion years. North and South America are slowly moving away westward from Africa and Europe as you read this. In the introversion model, the younger, interior, Atlantic Ocean, preferentially subducts and the current migration of North and South America is reversed. In the extroversion model, the older, exterior, Pacific Ocean preferentially subjects and North and South America migrate toward eastern Asia. However these geodynamic models will be subject to revision and possibly change. One computer simulation predicts a reorganisation of the mantle convection occurring over the next 100 million years, forming a supercontinent composed of Africa, Eurasia, Australia, Antarctica, South America around Antarctica. Regardless of the outcome of the continental migration, the subduction process continues to transport water to the mantle. After a billion years from now, about 27% of the current ocean mass will be sub ducted. If this process continues unmodified into the distant future, the subduction and release would reach equilibrium after 65% of the current ocean mass has been sub ducted.
The introversion model was proposed by Christopher Scotese and his colleagues. They mapped out predicted motions several 100 million years into the future as part of the Paleomap Project. In this scenario, 50 million years from now:
— The Mediterranean Sea would vanish
— Europe and Africa will collide to create a long mountain range extending to the Persian Gulf.
— Australia will merge with Indonesia, and Baja California will slide northward along the coast.
— New subduction zones will appear off the eastern coast of North and South America, and mountain chains will form along this coastlines.
— To the south, migration of Antarctica to the north will cause all of its ice sheets to melt. As well as melting of Greenland ice sheets, this will raise the average ocean level by 90 m (300 ft). Inland flooding of the continents will result in climate changes across the globe.
By 100 million years from now, the continental spreading will have maximum extent and the continents will then begin to coalesce. In 250 million years, North America will collide with Africa while South America will wrap around the southern tip of Africa. This will form a new supercontinent called Pangaea Ultima, with the Pacific Ocean stretching across about half of Earth. Antarctica will reverse direction and return to the South Pole to develop a new ice cap.
The extroversion model was proposed by Canadian geologist Paul F. Hoffman of Harvard University. In 1992, Hoffman extrapolated the current motions of the continents and predicted that North and South America will advance across the Pacific Ocean, pivot about Siberia until it begins to merge with Asia. He dubbed this supercontinent, Amasia. Later, Roy Livermore calculated a similar scenario and predicted that Antarctica would begin to migrate northward, and east Africa and Madagascar would move across the Indian Ocean to collide with Asia. The closure of the Pacific Ocean would be complete in about 350 million years, which will mark the completion of the supercontinent cycle. This cycle refers to the segregation and congregation of continents about every 400 - 500 million years. Once the supercontinent is built, plate tectonics may enter period of inactivity as the rate of subduction decreases by an order of magnitude. This period of stability could increase mantle temperature at a rate of 30 - 100 degrees C (54 - 180 degrees F) every 100 million years, which is the minimum lifetime of past supercontinents. Consequently, volcanic activity would increase which would dramatically affect Earth's environment. Collision of plates will result in formation of mountains, thereby shifting weather patterns and sea levels may decline due to increased glaciation. The rate of surface weathering may increase, which will increase the rate of burial of organic material. Global temperatures will decrease whilst atmospheric oxygen levels will increase. This, in turn, affects Earth’s climate, which further decreases global temperatures. All of these climate changes will result in rapid biological evolution as new niches emerge. Earth’s mantle will be insulated, which concentrates the flow of heat in specific regions, causing volcanism and flooding of large areas with basalt. Rifts will form and the supercontinent will separate once more. Earth may then experience a warming period, as occurred during the Cretaceous Period.
The iron-rich core region of Earth is divided into a 1220 km (760 mi) radius solid inner core and a 3480 km (2160 mi) radius liquid outer core. Earth’s rotation creates convective eddies in the outer core region, causing it to function as dynamo. This generates a magnetosphere about the Earth, deflecting particles from the solar wind, which prevents significant erosion of the atmosphere from sputtering. As heat from the ore is transferred outward toward the mantle, the inner boundary of the liquid outer core will freeze, thereby releasing thermal energy and causing the solid inner core to expand. Scientists know this because this iron crystallisation process has been continuing for about a billion years. In the modern era, the radius of the inner core is expanding at an average rate of about 0.5 mm (0.2 in) every year, at the expense of the outer core. Nearly all of the energy needed to power the dynamo is being supplied by this process of formation of the inner core. The growth of the inner core is expected to consume most of the outer core in 3-4 billion years time. This will result in a virtually solid core composing of iron and other heavy (metal) elements. The surviving liquid envelope will mainly consist of lighter elements which will undergo less mixing. Alternatively, if at some point plate tectonics reaches a terminal point, the interior will cool less efficiently, which would end the expansion process of the inner core. No matter the case, the loss of the magnetic dynamo is inevitable. Without a functioning dynamo, Earth’s magnetic fired will decay in a geologically short time period of approximately 10,000 years. The loss of the magnetosphere will increase the erosion of light elements, particularly Hydrogen, from Earth’s outer atmosphere into space. This will result in less favourable conditions for life to thrive on Earth.
https://en.wikipedia.org/wiki/Space_colonization
- Will we be able to visit other planets outside our solar system?
- If we successfully find and land on an exoplanet that is native to life, would we successfully thrive and colonise there?
- Would we be welcomed with open arms by extraterrestrials assuming they speak a different language and they view us as outsiders?
- Or would we be bringing along chaos leading to massacres, wars and imprisonment?
Many arguments have been made for and against space colonisation. The 2 most common reasons supporting colonisation include survival of human civilisation and the biosphere in the event of a planetary-scale disaster (natural or man-made), and the availability of additional resources in space that could enable expansion of human society. The most common objections to space colonisation including concerns of commodification of the cosmos enhancing the interests of the already powerful, including economic and military institutions, and to exacerbate pre-existing detrimental processes such as wars, economic inequality and environmental degradation.
In 2001, theoretical physicist and cosmologist Stephen Hawking argued for space colonisation as a means of saving humanity and predicted that the human race would become extinct within the next 1000 years, unless colonies establishes themselves in space. In 2006, Hawking states that humanity will have to choose between 2 options:
1. Either we colonise space within the next 2000 years and build residential units on other planets,
2. Face the prospect of long-term extinction.
So far, no space colonies have been built and building one would present huge technological and economic challenges. Space settlements would have to provide for nearly all the material needs of 100 or 1000s of humans, in an environment out in space that is quite hostile to human life. They would involve technologies like controlled ecological life support systems, that have yet to be developed in a meaningful way. They would also need to consider the unpredictable nature of humans in such places long-term.
Resources in space, both in materials and energy, are gigantic. According to different estimates, the Solar System alone has enough resources to support anywhere from several thousand to over a billion times that of the current Earth-based human population. Outside the Solar System, several 100 billion other stars in the observable universe provide opportunities for both colonisation and resource collection. Nevertheless, travelling to any of them is impossible on any practical time-scale without interstellar travel by use of generation ships or revolutionary new methods of travel, such as faster-than-light (FTL). Asteroid mining would be a critical step in space colonisation because asteroids might contain water and materials to help build structures and shielding. Instead of resupplying on Earth, mining and fuel stations would need to be established on asteroids to facilitate better space travel. NASA believes by using propellant extracted from asteroids for exploration to the moon, Mars and beyond may save $100 billion. If funding and technology arrive sooner than estimated, asteroid mining might be possible within a decade.
Because there isn’t any known space life, holocene extinction shouldn’t be a consequence according to some space settlement advocates. Space colonisation would help alleviate the negative effects of overpopulation. If the resources of space were opened to use and viable life-supporting habitats were constructed, Earth would no longer define the limitations of growth. Although many of Earth’s resources are non-renewable, off-planet colonies could satisfy the majority of Earth’s resource requirements. If there is availability of extraterrestrial resources, therefore demand on terrestrial resources would decrease. Additional goals cite the innate human drive to explore and discover, which is a quality that stimulates progress and thriving civilisations.
— Method: Building colonies in space would require access to water, food, space, people, construction materials, energy, transportation, communications, life support, simulated gravity, radiation protection and capital investment. The best place to build such colonies would be adjacent to the necessary physical resources. Building space architecture would not only test human endurance in spaceflight but also to form a normality within a bounds of comfortable experience. According to Neil deGrasse Tyson and John Hickman, funding the infrastructure necessary for space colonisation may come from government capital investments.
— Materials: Colonies on the Moon, Mars, or asteroids could extract local materials. The Moon is deficient in volatiles such as Argon, Helium and compounds of Carbon, Hydrogen and Nitrogen. The Cabeus crater on the Moon’s surface was targeted to be deemed having a high concentration of water ~ 1% or more. Water ice may be found in permanently shadowed craters near the lunar poles due to the extremely low surface temperatures there. Although Helium is present at low concentrations, where it becomes deposited into regolith by the solar wind, it’s estimated a million tons of Helium-3 exists over all. Furthermore, the Moon has industrially significant Oxygen, Silicon and metals such as Iron, Aluminium and Titanium. Launching materials from Earth is expensive, hence launching bulk materials from colonies on the Moon, a near-Earth-object (NEO), Phobos or Deimos may be cheaper. The benefits of using such sources include a lower gravitational force, lack of atmospheric drag on cargo vessels and lack of biosphere to damage. We know NEOs contain substantial amounts of metals and lying underneath a drier outer crust (like oil shale) are inactive comets which may contain billions of tons of water ice, Kerogen hydrocarbons and some Nitrogen compounds.
— Energy: Solar energy in orbit is abundant, reliable, and commonly used to power satellites today. There is no night in free space, no clouds, nor atmosphere to block sunlight, hence light intensity obeys an inverse-sqaure law. So the solar energy available at distance d from the Sun is E = 1367 / d^2 W/m^2, where d is measured in AU (Astronomical Units) and 1367 Watts/m^2 is the energy available at the distance of Earth’s orbit from the Sun, 1 AU.
In the weightlessness and vacuum of space, high temperatures for industrial processes can easily be achieved in solar ovens with huge parabolic reflectors made of metallic foil with lightweight support structures. Flat mirrors can reflect sunlight around radiation shields into living areas in order to avoid line-or-sight access for cosmic rays or to make the Sun’s image appear to move across their “sky”. If sunlight is reflected onto crops, the support structures would be even lighter and easier to build.
Large solar power photovoltaic cell arrays or thermal power plants would be required to satisfy the electrical power needs of the settlers’ use. In developed countries, electrical consumption on average is about 1 kW/hr or 10 MW/hr per person per year. These power plants could be located close to the main structures if wires are used to transmit the power or far away with wireless power transmission.
Large power satellites can transmit power wirelessly using phase-locked microwave beams or lasers emitting wavelengths onto special solar cells to be converted with high efficiency to send power to locations on Earth, to space colonies on the Moon or other locations in space. For locations on Earth, this method of transmitter power is benign, due to zero emissions and minimal ground area required per Watt than for conventional solar panels. Once these satellites are primarily built from lunar or asteroid-derived materials, the price of SPS electricity would be cheeper than energy derived from fossil fuels or nuclear energy, and replacing these would have significant benefits; most notably elimination of greenhouse gases and nuclear waste from electricity generation. For both solar thermal and nuclear power generation in airless environments such as the Moon and space and Mars to a lesser extent, one of the main difficulties is dispersing the inevitable heat generated. This would require fairly large radiator areas.
— Life Support: In space settlements, a life support system must recycle or import all nutrients without “crashing”. The closest terrestrial analogue to space life support is possibly that of a nuclear submarine, which use mechanical life support systems to support humans for months without surfacing. Although it can be employed for space use, nuclear submarines run “open loop”, that is extracting oxygen from seawater, dumping Carbon Dioxide but also recycling existing Oxygen. Recycling of the Carbon Dioxide has been approached using the Sabatier Process or the Bosch reaction. A closed ecological system like the Biosphere 2 project in Arizona is generally proposed for life support. The project involves a complex, small, enclosed, man-made biosphere that can support 8 people for at least a year. The problems that faced these people were replenishment of oxygen half-way into the 2-year mission, which strongly infers atmospheric closure. The relationship between organisms, their habitat and the non-Earth environment can be:
— Isolated between the environment, and the organisms and their habitat e.g. Artificial biosphere, Biosphere 2, life support system.
— Terraformation of an environment to become a life-friendly habitat
— Biological alteration of organisms to increase compatibility with their environment using techniques such as genetic engineering, transhumanism, or cyborg.
— Radiation Protection: Cosmic rays and solar flares create a lethal radioactive environment for humans in space. In Earth’s orbit, the Van Allen belts is the biggest obstacle to living above Earth’s atmosphere. To protect life, settlements would need to be surrounded by sufficient mass to absorb most incoming radiation, unless magnetic or plasma radiation shields are invented. Passive mass shielding of 4 metric tons per square metre of surface area can reduce annual radiation dosage to several mSv (milliSieverts) or less which is below the rate of some populated high natural background areas. This includes leftover material (slag) from processing lunar soil and asteroids into Oxygen, metals and other useful materials. Nonetheless, it presents a significant challenge when manoeuvring vessels with massive bulk. Inertia would necessitate powerful thrusters to begin or halt rotation, or electric motors to spin 2 passive portions of the vessel in opposite directions. Shielding material can be stationary around a rotating interior.
— Self-replication: Space manufacturing could enable self-replication which would allow an exponential increase in colonies, whilst eliminating costs to and dependence on Earth. Critics argue establishing such colonies would be Earth’s first act of self-replciation. Intermediate goals include colonies expecting only info from Earth such as science, engineering and entertainment, and other colonies requiring periodic supply of light weight objects such as integrated circuits, medicines, genetic material and tools.
— Psychological adjustment: During prolonged space missions, monotony and loneliness can leave astronauts susceptible to cabin fever or having psychotic breaks. Moreover, sleep deprivation, fatigue, and work overload can hamper an astronaut’s ability to perform well in an environment such as space where every action is critical.
— Population Size: In 2002, anthropologist John H. Moore estimated a population of 150 - 180 can stabilise society for 60 - 80 generations, which is equivalent to 2000 years. Smaller initial populations of as little as 2 women is viable as long as human embryos are available from Earth. The use of a sperm bank from Earth also permits a smaller starting base with negligible inbreeding. Researchers in conservation biology tend to adopted the “50/500” rule of thumb, which was initially advanced by Franklin and Soule. This rule describes a short-term effective population size (Ne) of 50 is needed to prevent an unacceptable rate of inbreeding. A long-term Ne of 500 is required to maintain overall genetic variability.
(Ne = 50): This prescription corresponds to an inbreeding rate of 1% per generation, approximately 50% of the maximum rate tolerated by domestic animal breeders.
(Ne = 500): This value attempts to balance the rate of gain in genetic variation due to mutation with the rate of loss due to genetic drift.
Say you’re on a journey lasting 6,300 years, astrophysicist Frédéric Marin and particle physicist Camille Beluffi calculated that the minimum viable population for a generation ship to reach Proxima Centauri would be 98.
Location: Space colonisation advocates are contending for the most suitable location to colonise humans. It can be on a physical body planet, dwarf planet, natural satellite, or asteroid or orbiting one.
— Moon: Although the Moon is a target due to its close proximity and familiarity to Earth hence it requires a lower escape velocity. This would allow easier exchanges of goods and services. However volatiles aren’t overly abundant on the Moon that is necessary for life such as Hydrogen, Nitrogen and Carbon. Water-ice deposits known to exist in some polar craters could serve as a source for these elements. Another solution would be to transport Hydrogen from near-Earth asteroids and combine it with Oxygen extracted from lunar rock. Nevertheless in contrast to Earth, Moon has a lower surface gravity i.e. (1/6)*g, which may not be enough to maintain human health for prolonged periods. Also its lack of atmosphere doesn’t provide crucial protection from space radiation or meteoroids. Early Moon colonies may shelter in ancient Lunar lava tubes to gain protection. Moreover, the 2-week day/night cycle makes solar power difficult to use for colonists.
https://en.wikipedia.org/wiki/Lagrangian_point
— Mercury: Colonising Mercury would involve similar challenges as the Moon as there are few volatile elements, no atmosphere and lower surface gravity than Earth’s. However, Mercury receives almost 7 times the solar flux as the Earth/Moon system. Geologist Stephen Gillett suggested Mercury would be an ideal place to build solar sails, and launch them as folded up “chunks” by mass driver from Mercury’s surface. Once in space, the solar sails will deploy. Since Mercury’s solar constant is 6.5 times higher than Earth’s, energy for the mass driver would be readily available. Therefore solar sails near Mercury would have 6.5 times the thrust they would unleash than Earth’s. This could make Mercury an ideal places to acquire materials useful in building hardware to send to (and terraform) Venus. Vast solar collectors could also be built on or near Mercury to produce power for large scale engineering activities such as laser-pushed light sails to nearby star systems.
— Venus: Aside from its hostile environment, this planet has similarities to Earth, which make colonisation easier in many respects in comparison with other possible destinations. These similarities, along with its proximity, make Venus Earth’s “sister planet”. Venus is similar to Earth in terms of size and mass, hence has a similar surface gravity i.e. 0.904g. This would likely be sufficient to prevent health problems associated with weightlessness such as bone decalcification and hypotonia. Venus’s relative proximity makes transportation and communications easier than for most other locations in the Solar System. With current propulsion systems, launch windows to Venus occur every 584 days. Flight time to Venus is about 5 months en route because Venus is 40 million km (25 million miles) from Earth. Venus’s atmosphere is made mostly of Carbon Dioxide. If we filter it from Sulphuric Acid, it can be used to grow food. Because Nitrogen and Oxygen are lighter than Carbon Dioxide, breathable-air-filled balloons will float at a height of about 50 km (31 mi). At this height, the temperature is a manageable 75 degrees C (167 degrees F); or 27 degrees C (81 degrees F) if we went 5km (3.1 mi) higher.
The temperature at Venus’s equator is about 450 degrees C (723 K, 842 degrees F), which is hotter than the boiling point of Lead (Pb) i.e. 327 degrees C. The atmospheric pressure on the surface is also at least 90 time greater than that on Earth, which is equivalent to being underwater 1km deep. These conditions are reasons missions to the surface are brief e.g. Soviet Venera 5 & 6 were crushed by high pressure 18km above the surface. Although Venera 7 & 8 successfully landed on the surface, they could only transmit data for an hour before aborting the mission. Furthermore, water is almost entirely absent from Venus. The atmosphere is devoid of molecular Oxygen and primarily consists of Carbon Dioxide. Moreover. the visible clouds are composed of corrosive Sulfuric Acid and Sulfur Dioxide vapour.
Geoffrey A. Landis of NASA’s Glenn Research Centre proposed aerostat habitats followed by floating cities. This is based on the concept that breathable air (21:79 Oxygen:Nitrogen mixture) is a lifting gas in the dense Carbon Dioxide atmosphere, with over 60% of the lifting power that Helium has on Earth. In effect, a balloon full of breathable air would sustain itself and the extra weight in midair. At an altitude of 50 km (31 mi) above the Venerian surface, the environment is the most Earth-like in the Solar System. The pressure there is approximately 1000 hPa and temperatures range from 0 - 50 degrees C (273 - 323 K; 32 - 122 degrees F). Protection against cosmic radiation would be provided by the atmosphere above, with shielding mass equivalent to Earth’s. The wind speed at the top of the Venerian clouds reaches up to 95 m/s (340 km/hr, 210 mph). A balloon there would circle Venus approximately every 4 Earth days in a phenomenon called “super-rotation”. Colonies floating in this region would have a shortened day length by remaining untethered to the ground and moving with the atmosphere, compared to the usual 243 Earth days it takes for the planet to rotate. Allowing a colony to move freely would reduce structural stress from the wind. Because there isn’t a significant pressure difference between the interior and exterior of the balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates rather than an explosive decompression. This gives the repair crew time to fix any such damages. In addition, humans won’t require pressurised suits when outside. It’s merely breathable air and they are already protected from the acid rain and heat. Alternatively, 2-part domes could contain a lifting gas like Hydrogen or Helium to allow a higher mass density. Therefore, putting on or taking off suits for working outside and working outside the vehicle in non-pressurised suits would be manageable.
Retrieving Hydrogen, water and metals from the surface still remains an issue and transporting it from Earth / asteroids would be quite expensive. Although water can be extracted from the sulphuric acid in the clouds, sulphuric acid itself poses a further challenge which requires colonies constructed of or coasted in materials resistant to corrosion by the acid, such as PTFE (A compound consisting of Carbon and Fluorine).
Building large artificial mountains, called the “Venusian Tower of Babel”, on the Venerian surface reaching up to 50 km (31 mi) into the atmosphere has been proposed as an alternative. Such a megastructure requires the use of autonomous robotic bulldozers and excavators hardening against the extreme temperature and pressure of the Venus atmosphere. Such robotic machines would be protected in a layer of heat and pressure shielding ceramics. They could contain internal Helium-based heat pumps inside the machines to cool both an internal nuclear power plant and keep the internal electronics and motor actuators cooled to with in operating temperatures. The design has to meet the requirement of year-long operations without external interevent for the purpose of building colossal mountains on Venus to serve as islands of colonisation in the skies of Venus.
A number of terraforming proposals seek to remove or convert the dense Carbon Dioxide atmosphere, reduce Venus’s 450 degrees C (723 K; 842 degrees F) surface temperature, and establish a day/night light cycle closer to that of Earth. Proposals include deployment of a solar shade or a system of orbital mirrors, for the purpose of reducing insolation and providing light to the dark side of Venus. Other proposals involves introduction of large quantities of Hydrogen or water, freezing most of Venus’s atmosphere Carbon Dioxide or converting it to Carbonates, Urea or other forms.
https://en.wikipedia.org/wiki/Colonization_of_Venus
— Mars: This planet’s surface conditions and possible past presence of water make it arguably the most hospitable planet in the Solar System besides Earth. Mars requires less energy per unit mass (ΔV) to reach from Earth than any planet, except Venus. Mars’ similarities to Earth are more compelling when consider colonisation.
-- A Martian day (or sol) is close to duration to Earth’s. A solar day on Mars in 24 hours, 39 minutes and 35.244 seconds.
-- Mars’ surface area is 28.4% of Earth’s, which is slightly less than the amount of dry land on Earth (which is 29.2% of Earth’s surface). Mars’ radius is half of Earth’s radius and only 1/10th of Earth’s mass. This means Mars has a smaller volume (~15%) and lower average density than Earth.
-- Mars has an axial tilt of 25.19 degrees, similar to Earth’s 23.44 degrees. Therefore, Mars has seasons much like Earth, though they last nearly twice as long because the Martian year is about 1.88 Earth years. The Martian north pole currently points at Cygnus, not Ursa Minor like Earth’s.
-- Recent observations by NASA’s Mars Reconnaissance Orbiter, ESA’s Mars Express and NASA’s Phoenix confirm the presence of water ice on Mars.
-- Although there are some extremophile organisms that can survive in hostile conditions on Earth, plants and animals generally can’t survive the ambient conditions present on Mars’s surface.
Surface gravity of Mars is 38% that of Earth. Although microgravity is known to cause health problems such as muscle loss and bone mineralisation, it’s unknown if Martian gravity elicits a similar effect.
-- Mars is much colder than Earth, with mean surface temperatures between 186 and 268 K (—87 & 5 degrees C; —125 and 23 degrees F) depending on your position. The lowest temperature ever recorded on Earth was 180 K (—89.2 degree C, —128.6 degrees F) in Antarctica.
-- Surface water on Mars may occur transiently, but only under certain conditions.
-- Because Mars is about 52% farther from the Sun, the amount of solar energy entering its upper atmosphere per unit area (Solar Constant) is around 43.3% of solar energy reaching Earth’s upper atmosphere. However due to the much thinner atmosphere, a higher proportion of the solar energy reaches the surface. The maximum solar irradiance on Mars is about 590 W/m2 compared to about 1000 W/m2 at Earth’s surface. Also, year-round dust storms may obscure the sun’s rays for weeks at a time.
-- Mars’s orbit is more eccentric than Earth’s. which increases temperature and solar constant variations.
-- Due to the lack of a magnetosphere, solar particle events and cosmos rays can easily reach the Martian surface.
-- Mars's atmospheric pressure is below the Armstrong limit at which people can survive without pressure suits. Since terraforming can’t be expected as a short-term solution, habitable structures on Mars would have to be constructed with pressure vessels similar to spacecraft, which are capable of containing pressures between 30 and 100 kPa.
-- Armstrong limit = 6.25 kPa (0.906 psi)
-- Earth sea level = 101.3 kPa (14.69 psi)
-- Mars average = 0.6 kPa (0.087 psi)
-- Mount Everest summit = 33.7 kPa (4.89 psi)
-- The Martian atmosphere is 95% Carbon Dioxide, 3% Nitrogen, 1.6% Argon and traces of other gases including Oxygen totalling less than 0.4%.
-- The thin atmosphere doesn’t filter out UV sunlight.
Conditions on Mars’s surface are similar to Earth’s in terms of temperature and sunlight. Nevertheless, this surface isn’t hospitable to humans or most known life forms due to greatly reduced air pressure and an atmosphere with only 0.1% oxygen. A 2012 study discovered some lichee band cyanobacteria demonstrated survival and remarkable adaptation capacity for photosynthesis after 34 days in simulated Martian conditions in the Mars Simulation Laboratory (MSL) maintained by the German Aerospace Centre (DLR). This suggests cyanobacteria could play a role in the development of self-sustainable manned outposts on Mars, and directly for various applications which include food, fuel and oxygen production. Indirectly, their cultural production could support the growth of other organisms, which would pave the way to a vast range of life-support biological processes based on Martian resources.
Different technologies have been developed to asset long-term space exploration in order t be adapted for human habitation on Mars. The current world record for the longest consecutive space flight is 438 days by cosmonaut Valeri Polyakov. The current world record for the must accrued time in pace is 878 days by Gennady Padalka. The longest time spent outside Earth’s protective Van Allen radiation orbit is about 12 days for the Apollo 17 moon landing. Many different biological functions can be negatively impacted by Mars’s environment and higher levels of radiation reaching Mars’s surface. The lower gravity (~ 38% of Earth’s gravity) poses negative human health impacts such as weakened bones and muscles, osteoporosis and cardiovascular problems. Current rotations on the International Space Station (ISS) put astronauts in zero gravity for 6 months, making it a comparable length of time to a 1-way trip to Mars. Upon returning to Earth, recovery from osteoporosis and muscle atrophy is a long arduous process and the effects of microgravity may be irreversible. Radiation on Mars can pose severe risks regarding cognition, cardiovascular health, reproduction and cancer.
Due to communication delats, new protocols would need to developed to assess the psychological health of all crew members. A Martian simulation called HI-SEAS (Hawaii Space Exploration Analog and Simulation) places scientists in a simulated Martian laboratory in order to study psychological effects of isolation, repetitive tasks, and living in close-quarters with other scientists for up to a year at a time. Computer programs are currently being developed to assist crews with personal and interpersonal issues in the absence of direct communication with professionals on Earth. There are suggestions to select individuals who have passed psychological screenings and recruit them for Mars exploration and colonisation missions. Psychosocial sessions for the return home are also suggested in order to reorient people to society.
Because Mars doesn’t have a global magnetosphere as well as having a thin atmosphere, a significant amount of ionising radiation is reaching the Martian surface. Radiation levels in orbit above Mars are about 2.5 times higher than at the International Space Station. The average daily dose was about 220 μGy (22 mrad), which is equivalent to 0.08 Gy per year. Exposed to these radiation levels for 3 consecutive years would reach the safety limits currently adopted by NASA. Levels at the Martian surface would be somewhat lower and might vary significant;y at different locations depending on the altitude and local magnetic fields. Building living quarters underground in Martian lava tubes would significantly lower the colonists’ exposure to radiation.
Using a Hohmann transfer orbit, a trip to Mars lasts about 9 months in space. Modified transfer trajectories that cut down travel time to 4-7 months in space are possible with incrementally higher amounts of energy and fuel. Shortening the travel time below 6 months requires a higher ΔV and an exponentially increasing amount of fuel, which is difficult to execute with chemical rockets. Advanced spacecraft propulsion technologies such as Variable Specific Impulse Magnetoplasma Rocket, and nuclear rockets could make this shorter journey possible. During the journey the astronauts would be subject to cosmic radiation and solar wind. This radiation directly cause damage to our DNA, which increases the risk of cancer significantly. Although it’s currently unknown, but estimates of long-term travel in interplanetary space include an added risk of between 1% and 19% for men to die of cancer. For women the probability is higher because they have larger glandular tissues.
Mars’s relatively strong gravity and the presence of aerodynamic effects make it difficult to land heavy, crewed spacecraft with thrusters only. Also the thin atmosphere makes it difficult for aerodynamic effects to assist in aerobraking and landing large vehicles. Therefore, landing piloted missions on Mars would require unique breaking and landing systems. If one assumes Carbon nanotube construction material will be available with a strength of 130 GPa then a space elevator could be built to land people and material on Mars.
https://en.wikipedia.org/wiki/Colonization_of_Mars
— Asteroid Belt: The asteroid belt has significant overall material available but colonising these asteroids requires space habitats; amongst them is the largest object called Ceres. Unmanned supply spacecraft would be practical with minimal technological advance, even crossing 500 million km of space. The challenge for colonists is to assure their asteroid doesn’t impact Earth or any other body of significant mass and controlling its movement. The orbits of Earth and other asteroids are quite distant from each other in terms of ΔV and the asteroidal bodies have enormous momentum. Rockets or mass drivers are proposed to be installed on asteroids in order to direct their path along a safer course.
— Jovian Moons (Io, Europa, Callisto & Ganymede): The Artemis Project designed a plant colonise Europa, one of Jupiter’s moons. The project involves scientists inhibiting igloos and drilling down into the Europan ice crust to explore the sub-surface ocean. This plan discusses possible use of “air pockets” for human habitation. A NASA study called HOPE (Human Outer Planet Exploration) took an interest in Callisto due to its distance from Jupiter, and thus its harmful radiation. It could be possible to build a surface base that produces fuel to be used for further exploration of our Solar System.
— Moons of Saturn (Titan, Enceladus, and others): Titan is a possible target for colonisation because it’s the only moon in the Solar System that has a dense atmosphere, abundant in carbon-bearing compounds and as well as ice water and large methane oceans. This elements are critical in supporting life, which could make it the most advantageous locale in the outer Solar System for colonisation. It may be the most hospitable extraterrestrial world within our solar system for human colonisation. Enceladus is a small, icy moon that orbits close to Saturn. It notable for its extremely bright surface and geyser-like plumes of ice and water vapours erupting from its southern polar region. If Enceladus has liquid water, it joins Mars and Jupiter’s moon Europa as one of the prime places in the Solar System to search for extraterrestrial life and possible future settlements. Other large natural satellites such as Rhea, Iapetus, Dione, Tethys and Mimas all have large quantities of volatiles, that can support settlements.
— Trans-Neptunian region: The Kuiper belt is estimated to have 70,000 bodies of 100 km or larger. Freeman Dyson suggested humans will civilise there within a few centuries. The Oort Cloud is estimated to have up to a trillion comets.
— Outside the Solar System: There are up to several 100 billion potential stars that are proposed as potential colonisation targets. However they are quite far away, about 100,000 times further away than the planets in the Solar System. This requires a combination of extreme speed near the speed of light, or travel times lasting centuries or millennia. These speeds are far beyond what current spacecraft propulsion systems can provide. I’ll delve into the challenges, proposals overcoming these challenges, objectives and possibilities of interstellar travel in another post.
— Funding: Space colonisation can be made possible when the necessary requirements become affordable to meet the cumulative funds that have been collected for this purpose. Launching cargo weighing up to 13.15 metric tons (28,990 lb) to low Earth orbit costs about US$56.5 million. SpaceX Falcon 9 rockets are the cheapest rockets in the aeronautics industry so far. They’re being developed as part of the SpaceX reusable launch system development program to enable reusable Falcon 9s. This would reduce the cost by an order of magnitude, sparking more space-based enterprise, hence it would reduce the cost of access to space still further through economies of scale. If successful, it would revolutionise the increasingly competitive market in space launch services. The President’s Commission on Implementation of United States Space Exploration Policy suggested establishing an inducement prize to mark the achievement of space colonisation. e.g. Offering the prize to the first organisation to place humans on the Moon and sustain them for a fixed period before they return to Earth.
— Planetary Protection: Robotic spacecraft to Mars are required to be sterilised. They may have at most 300,000 spores on the exterior. Thorough sterilisation is mandatory if spacecraft contact “special regions” containing water, otherwise there is a risk of contaminating not only life-detecting experiments but possibly the planet itself. It’s impossible to strictly sterilise human missions because humans are host to a 100 trillion microorganisms of 1000s of species of the human microbiome. These cannot be removed whilst preserving the life of the human. Containment seems the only option, but it’s a major challenge in the event of a hard landing (i.e. crash). Several planetary workshops are currently addressing this issue, but they lack final guidelines to progress forward. Human explorers would also be vulnerable to back contamination to Earth if they become carriers of microorganisms.
How and when will the universe end?
https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe
Observations made by Edwin Hubble during the 1920s - 1950s found that galaxies appear to be moving away from each other, leading to the currently accepted Big Bang Theory. This suggests that the universe began from a minuscule and compact point about 13.8 billion years ago, and it has expanded and became less dense ever since. In order to confirm the Big Bang, cosmologists require knowledge of the rate of expansion, average density of matter, and the physical properties of the mass / energy in the universe. The factors determining the universe’s origin and ultimate fate include: the average motions of galaxies, the shape and structure of the universe, and the amount of dark matter and dark energy that the universe contains. The theoretical scientific exploration of the ultimate fate of the universe became possible with Albert Einstein’s 1915 theory of General Relativity. General Relativity can be employed to describe the universe on the largest possible scale. There are possible solutions to the equations of general relativity, and each solution implies a possible ultimate fate of the universe. In some of these solutions, it implies that the universe may have expanded from an initial singularity, essentially the Big Bang. I’ll delve into Einstein’s Theory of General Relativity in another post.
An important parameter in the fate of the universe theory is the density parameter labelled Omega (Ω), defined as the average matter density of the universe divided by a critical value of that density. This selects 1 of 3 possible geometries depending on whether Ω is equal to, less than, or greater than 1. These are called flat, open and closed universes, respectively. These 3 adjectives describe the overall geometry of the universe, and not to the local curving of space-time caused by smaller clumps of mass e.g. Galaxies and stars. If the primary content of the universe is inert matter i.e. 20th century dust models, there is a particular fate corresponding to each geometry. Cosmologists are aiming to measure Ω or equivalently the rate at which the expansion was decelerating in order to determine the fate of the universe. Observations of supernovas in distant galaxies suggest the universe’s expansion is accelerating. Subsequent cosmological theories propose the presence of dark energy, which in its simplest form, is a positive cosmological constant. Generally dark energy is an umbrella term for any hypothesised field with negative pressure, usually with a density that changes as the universe expands.
The ultimate fate of the universe depends on its overall shape, how much dark energy it contains, and on the equation of state which determines how dark energy density responds to the expansion of the universe. Recent observations conclude that from 7.5 billion years after the Big Bang, expansion rate of the universe has been increasing, which commensurates with the Open Universe Theory.
— If Ω > 1, then the geometry of space is closed like the surface of a sphere. The sum of the angles of a triangle exceeds 180 degrees and there aren’t any parallel, hence all lines eventually meet at a certain point. The geometry of the universe is elliptic. In a closed universe, gravity will halt the expansion of the universe, after which will start to contract until all matter in the universe collapse to a point called a final singularity. This is termed the “Big Crunch”, the opposite of a Big Bang.
— If Ω < 1, then the geometry of space is open i.e. negatively curved like the surface of a saddle. The angles of a triangle sum to less than 180 degrees, and lines that don’t meet are never equidistant. Instead they have a point of least distance and otherwise grow apart. The geometry of such a universe is hyperbolic. Even if there’s no dark energy, a negatively curved universe expands forever, with gravity negligibly slowing the rate of expansion. But if there’s dark energy present, the expansion will continue at an accelerating rate. So the ultimate fate of an open universe is either universal heat death, the “Big Freeze”, or the “Big Rip”, where the acceleration caused by dark energy eventually becomes incredibly powerful that it overwhelms the effects of the gravitational, electromagnetic and strong binding forces. — If Ω = 1, where the average density of universe exactly equals the critical density, then the geometry of the universe would be flat in Euclidean geometry. This refers to the sum of the angles of a triangle is exactly 180 degrees and parallel lines continuously maintain the same distance. In the absence of dark energy, a flat universe can expand forever but at a continually decelerating rate, with expansion asymptotically approaching zero. With dark energy, the expansion rate of the universe initially decelerates, due to the effect of gravity, but eventually increases. Nevertheless, the ultimate fate of the universe matches that of an open universe.
So far, observations aren’t conclusive within the margin of error, and alternative models are still possible:
(a) Big Freeze or Heat Death = This scenario can occur under which continued expansion results in a universe that asymptotically approaches absolute zero temperature (0 K, - 273 degrees C). In the absence of dark energy, the Big Freeze would occur only under a flat or hyperbole geometry.
With a positive cosmological constant, it could also occur in a closed universe. Stars would form normally for 1012 to 1014 (1 - 100 trillion) years, but eventually the supply of gas required for star formation will be exhausted. As existing stars run out of fuel and cease to shine, the universe will gradually and inexorably darken. Eventually black holes will dominate the universe, which themselves will disappear over time as they emit Hawking radiation. Over an infinite amount of time, entropy would spontaneously decrease by the Poincaré Recurrence Theorem, thermal fluctuations, and the Fluctuation Theorem. A related scenario is called Heat Death, which states that the universe reaches a maximum entropy state when everything is evenly distributed hence no gradients. Gradients are important to sustain information processing, one form of which is life. This scenario is compatible with any of the 3 spatial models, but it requires that universe reach an eventual minimum temperature.
(b) Big Rip = In a special case of phantom dark energy, which has more negative pressure than a simple cosmological constant, the density of this dark energy increases with time. This causes the rate of acceleration to increase, leading to an increase in the Hubble Constant. As a result, all material objects in the universe from galaxies to eventually all forms in finite time, big and small, will disintegrate into unbound elementary particles and radiation. They will be ripped apart by the phantom energy force and ricochet apart from each other. The end state of the universe is a singularity, as the dark energy density and expansion rate becomes infinite.
(c) Big Crunch = This hypothesis takes a symmetric view of the ultimate fate of the universe. It assumes that the average density of the universe will be enough to stop its expansion and begin contracting. Nonetheless, the end result remains unknown. Estimates would have all matter and space-time in the universe collapse into a dimensionless singularity back into the origin of universe with the Big Bang. But at these scales, there are unknown quantum effects that need to be considered such as Quantum gravity. Recent evidence reduces the likelihood of this scenario occurring but it hasn’t been ruled out as measurements are only available briefly and could reverse in the future. Nevertheless, this scenario allows the Big Bang to occur immediately after the Big Crunch of a preceding universe. If this occurs repeatedly, it generates a cyclic model, also known as an oscillatory universe. The universe could then consist of an infinite sequence of finite universes, with each finite universe ending with a Big Crunch followed by the Big Bang of the awaiting universe. Theoretically, a cyclic universe wouldn’t reconcile with the 2nd law of Thermodynamics because entropy would accumulate from continuous oscillations and cause heat death. Current evidence indicates the universe is open rather than closed, hence it led to the abandonment of the oscillating universe model.
(d) Big Bounce = This theoretical scientific model relates to the beginning of the known universe. It derives from the oscillatory universe or cyclic repetition interpretation of the Big Bang where the first cosmological event was the result of a collapse of a previous universe. It states that the universe will continuously repeat the cycle of a Big Bang, followed by a Big Crunch.
(e) False Vacuum = The false vacuum collapse theory involves the Higgs field which permeates the universe. Much like an electromagnetic field, the Higgs field varies in strength based upon its potential. A true vacuum, with zero particles within a confined space (container), can exist in its lowest energy state, in which case the false vacuum theory is irrelevant. However, if the vacuum isn’t in its lowest energy state, it could tunnel into a lower energy state. This is called vacuum decay, which could fundamentally alter our universe. It’s possible that all structures will be destroyed instantaneously, without any forewarning. Studies of a particle similar to the Higgs Boson support the theory of false vacuum collapse billions of years from now.
Each possibility described above is based on a simple form for the dark energy equation of state. However experts don’t fully understand the physics of dark energy. If the theory of inflation is validated, it would mean the universe experienced an episode dominated by a different form of dark energy during the initial moments of the Big Bang. Nevertheless, inflation has ended, which indicates an equation of state substantially complex than those assumed so far for present-day dark energy. It’s possible that the dark energy equation of state is subject to change which would result in an event that could cause unpredictable and un-parametisable consequences. As the nature of dark energy and dark matter remain enigmatic and hypothetical, the possibilities surrounding their coming role in the universe are currently unknown.
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