More than 90% of all species that arose since life began on Earth 3.8 billion years ago are extinct. Modern Humans arose about 200,000 years ago. We are different from all preceding species in that we are self-consciously intelligent but does that mean that our fate is different to that of the 90% already extinct.
Our survival depends on our ability to overcome existential threats. Some threats are self-imposed and some natural; ballooning world population growth – self-imposed; global nuclear war – self-imposed; global warming – self-imposed; asteroids and comets – natural; cyclical long-term natural climate change – natural; a much hotter sun – natural.
Our ultimate destiny is to be baked, blasted, and eventually disintegrated. There is nothing we can do to prevent this cataclysm. Yet according to scientists who study the far future, the prospect for life is rather bright. Given technological advances and the continuing evolution, Humans should be able to survive – in some form – long after Earth has ceased to exist.
The first major cosmic crisis will strike in 1.5 billion years. At that point, the brightening sun will set off super-global warming. Earth will be heated until the oceans boil.
As the sun grows hotter, other planets will become appealing. Just as Earth becomes too hot to sustain life, Mars will reach a temperature that makes it habitable for another 5 billion years.
7.5 billion years from now the sun will exhaust its hydrogen fuel and switch to helium. That will cause it to balloon into an enormous red giant. Mars as well as Earth will be fried.
On the other hand, the once icy moons of Jupiter and Saturn will have become tropical water worlds – prime real estate for Human colonies. We could live there for a few hundred million years.
8 billion years from now, the flaring sun will make conditions intolerably hot all the way out past Pluto. Life will be impossible in our solar system. There are 200 billion stars in the Milky Way, most with planets of their own. Perhaps our descendants will have mastered near-light-speed travel.
50 to 100 billion years from now, all of the raw material for new stars will be used up. The last sunlike stars will burn out and Humans will need a new place to live.
The Milky Way is dotted with red dwarfs, cooler and dimmer than our sun but built to last. So planets around red dwarfs may be our homes until 15 trillion years from now, when they too will expire.
Red dwarfs will be the last generation of stars. Once they die, the universe will go dark. In this dark future, we might build enormous space power plants around black holes.
Trillions of years of evolution will have long since transformed us. Perhaps we will have merged with our computers. Perhaps we will not even have a physical form.
This gravitational era that begins around 15 trillion years from now could continue for quintillion years and beyond. A quintillion is a 1 followed by 18 zeroes. It is trillion times as long as the entire history of our hominid line on Earth. At some point, life runs into the physical limits of matter itself.
Sometime between 10^34 (1 decillion) and 10^64 (1 vigintillion) years from now, the protons will decay. Black holes will be the only organized form of matter in the universe.
Future humanity can not have any physical form at this point. At 10^100 (10 duotrigintillion) years from now even black holes will evaporate. There will be no energy or structures of any kind – just a cold, eternal mist of farflung particles. This really is the end point for life.
Or maybe not …