Good morning Australia and welcome to another edition of "Ask ARSE" where we delve deep into the unknown and search for nuggets of truth at the request of our beloved followers.
Today we have an email inquiry from a good friend of ARSE who wondered:
"Hey guys my name is Michael and I love the page. Have you thought about making a YouTube channel? I was watching a YouTube documentary about the size and scale of the universe especially how everything takes millions of years to happen and we are a blink in the eye of time. What I was wondering was what does the future hold for Earth and the universe? When does it all end? It has to end some time right? Thanks guys and keep spreading ARSE"
Interesting question there mate and one that has been ruminated over for quite a while now. Especially since the year, we've had seems to be sending the entire world down the dunny. That is a lot of question with a lot of answer, so we're going to break it up into a two part answer - one part for Earth and another the universe.
The most likely scenario, which is up for debate, is that the Big Freeze will happen when the seemingly unending expansion of the universe will leave nothing but subatomic particles.
There are also theories where the universe never ends, and humanity finds ways to band together in the face of annihilation. But that doesn't exactly answer your question though, does it?
So, taking the perspective of your question - if Earth and the universe does end - we'll try and provide a logical answer based on evidence.
There are a lot of experts in the field of 'Earth' and 'universe death' with even more answers, but we'll stick with this as our "gun to the head' answer with a hypothetical storytelling twist.
And we begin...
In about 1,000 years, human cultures will have melded into a global hive of similar traits. There will have been vast advances in communication that make our internet seem archaic. Languages become more congealed and a global consciousness will emerge.
Human-made climate change has heated our oceans and innumerable species of marine life are extinct. Most of the carbon dioxide from this current century will still be lingering in the atmosphere in the year 3020. The seas have risen by about 4 metres which devastates entire coastlines, cities and ecosystems.
The West Antarctic ice sheet has collapsed. Heating is concentrated in the polar regions of Earth and the mean average temperature here is increased by 3 degrees Celsius. This change alone means Methane - a more harmful greenhouse gas than CO2 - trapped in the permafrost is released and contributes a rapid change of 0.06 degrees Celsius. Global average temperatures rise by 8 degrees Celsius, meaning large bodies of freshwater evaporate and fall onto cooler parts of Earth in disastrous floods. Entire populations are left without water and starvation from lack of irrigation is commonplace.
13,000 years on, Earth's axial tilt will reverse and the seasons with it. Southern Hemisphere winter starts in December, and summer begins in July. The Northern Hemisphere, where most of Earth's population resides, is met with mass migrations south where weather patterns are less unpredictable.
Carbon dioxide levels are slowly dropping, although humanity only has an approximate 95% chance of survival.
In 20,000 years, Chernobyl has become habitable again. The Arecibo message sent in November 1974 reaches its destination in the globular cluster Messier 13 at the far side of our galaxy. If there are extra-terrestrial beings here, they will have received a near 18,000-year-old message. Too late to change it to an SOS though.
In 30,000 years, all nuclear reactors will have reached their peak shelf life and will be decommissioned. If Earth has not accustomed to our rate of demand in energy, Earth will be plunged into darkness.
In 40,000 years, Voyager II will pass 1.7 lightyears from the star Ross 248.
In 50,000 years, erosion has made many water systems into boiling swamp flats unable to sustain life.
According to Berger & Loutre's paleoclimatic paper 'The Earth's Climate in the Next Hundred Thousand years (100 kyr)', Earth will then fall into an ice age.
For the next 50,000 years (102,020 years from now), providing humanity in some way or form has survived, there are no continuations of our current societal norms including politics, religion and culture. will be in place with no formal countries left. It is theorised that VY Canis Majoris, an extreme oxygen-rich hypergiant star 3914 lightyears away will explode and be visible from Earth.
The probability of the Yellowstone super volcano erupting is almost a certainty at this point if it hasn't already. Ash is thrown into the sky which blacks out the sun and causes global temperatures to plummet below freezing.
If humans are still alive, either here or Mars, we should (by that logic) have the technology to survive. If we have begun terraforming Mars, it will be close to completion at this time.
At nearly 300,000 years from now, Voyager II passes within five lightyears of Sirius, the brightest star in the sky.
In 500,000 years from now, the likelihood of Earth receiving a mass asteroid below an extinction-level event reaches the high ninety percentile.
The asteroid will most likely be around 1km in diameter, with an impact of 6 × 10^4 megatons. For reference, 1 megaton is 1 million tonnes of TNT. The shock causes a 9.4 magnitude planet-wide Earthquake. While large, it is not a world-ending event, but could still eliminate any traces of human life clinging onto Earth.
In 1,000,000 years, most artificial materials including glass have decomposed. This means all human structures, including entire cities, will have their remains eroded. Stone structures such as the pyramids will still stand but will be unrecognisable.
In 2,000,000 years, our coral reefs will begin rebuilding in oceans that have reached a Goldilocks zone of habitability. Ocean acidification subsides and life, in a much more cellular level, will thrive underwater. In 7,200,000 years almost no sign of our civilised existence will remain, except for some decomposed pieces of trash and plastics. If aliens have received and responded to our messages and ventured to greet us, most likely no one will be home.
It is theorised that Earth will be hit by a mass gamma radiation in 10,000,000 years.
If humans have somehow endured in 27,000,000 years, we would be unrecognisable from homo sapiens. Humans on Mars would have adapted to the demands of our terraformed environment, humans on Earth would have done the same. If there are space colonies, they most likely would have left to find another home elsewhere in the Solar System.
At this time, nuclear power and weapons would be primitive technology in comparison to the capabilities, including space travel.
In 50,000,000 years from now, if humanity did leave Earth and begin searching for other home worlds, we would have either died out long before or dominated the galaxy at this point. It's near impossible to get an accurate range of when this would happen.
Back on Earth the continents have collided and created huge mountain ranges from the tectonic plates moving over one another. Neighbouring continents become one such as Europe and Africa, or Australia and most of South-East Asia. Antarctica moves north and melts in the warmer climate, bringing sea levels up by 75 metres causing near-total flooding. The poor settlers on Mars will watch the moon Phobos smash into it with a large probability of killing everything on the planet.
In 100,000,000 years from now, Earth is most likely to be hit by a mega-colossal asteroid. Much like what killed off the dinosaurs. Its size would mean that we could not divert it with deflection means even if we had invented them. Again, this is purely the numbers of probability and only becomes higher if the asteroid hasn't already hit Earth. If we are still kicking, we soon wouldn't be. Earth's orbit has become unstable and random which devastates every ecosystem on Earth in an ever-changing and fluctuating climate. Saturn’s rings have either disappeared or clustered to form moons again, only to be smashed apart a few million years later. If you believe Dr Frank Drake's estimates of colonisation of space, this is as far as humans will ever venture to live.
That's it for part one of this two-parter but hang with us for the next instalment next week where we examine the future of the universe. If you've enjoyed this little extrapolation on the future of our little blue ball, share with a friend and help spread ARSE.