The+big+freeze+and+other+events+in+the+distant+future

Eventually humans will evolve or simply die off. Earth will (hopefully) still be around. That is until millions of years from now, in the distant future.

[] __The Big Freeze__ This is a theory that reasons: because the Earth is expanding, and cooling, it will eventually get too cold to sustain life.
 * how it works - a cosmological constant accelerates the rate at which the universe is expanding, the space between galaxies will grow, and redshift will stretch photons to long wavelengths and very low frequencies
 * stars will continue to form until all the gases they need to form run out
 * the proton decay theory suggests stellar remnants would disappear, leaving black holes
 * black holes, because they emit Hawking Radiation, would eventually disappear
 * if the universe ends up with an almost uniform temperature, no more work will be possible, resulting in a final heat death for the universe

__In the slightly nearer future. . .__ Right now the universe is about 13.7 billion years old, and in the Stelliferous era. 3 billion years later, it is possible that the Milky Way and Andromeda could collide (but the collision might not happen). And remember, Earth might be gone by the time the two galaxies collide, or the universe is no longer habitable. The descendants of humans could live on other planets, or space stations, or in a parallel universe. Who knows?

__ The Big Rip __ The Big Rip hypothesis suggests that all matter in the universe is torn apart by the expansion of the universe, at a certain time in the future.
 * How it works - phantom dark energy (which has negative pressure) increases in density with time, causing the rate of acceration to increase
 * This leads to an increase in the Hubble Consonant (a rather confusing law that has to do with the fact that all objects in space have a relative velocity to each other and Earth, and the velocity of galaxies receding from Earth is proportional to to their distance from Earth and each other, and therefore the universe is expanding, and it's bigger than it was, say, 10 years ago).
 * as a result all matter will be ripped apart and disintegrated by the energy force that is expanding. All this unbound matter will become elementary particles and radiation

__ The Big Crunch __ This theory states that the universe will come to a symmetrical end, a sort of opposite to the Big Bang theory.
 * how it works - the average density of the universe is large enough to stop its expansion
 * The end result is unknown: all matter and space-time could collapse into a singularity, but unknown quantum effects need to be considered
 * this hypothesis could mean that the Big Bang might have been immediatly preceded by the Big Crunch of a past universe, leading to the oscillatory universe: an infinite sequence of finite universes
 * several arguments caused scientists to abandon the oscillating universe idea

media type="youtube" key="NpjcOG4vkEY" width="425" height="350" a simulated video of the Big Crunch []

__Multiverse__ Though there are several muliverse hypotheses, one states that our universe is the product of one of infinite Big Bangs, all spread over infinite distances. As all these universes collide, the matter and antimatter annihilate, releasing energy. As old universes (or "verses", because there are more than one of them) annihilate, new ones are formed. So as the multiverse keeps expanding, as a whole it may never completely end.

Above is a timeline of the universe. [] Back