Theories about the end of the universe. The fate of the universe may be determined by its density. The preponderance of evidence to date, based on measurements of the rate of expansion and the mass density, favors a universe that will continue to expand indefinitely, resulting in the "Big Freeze" scenario below.
Scientists now consider it unlikely the universe has an end – a region where the galaxies stop or where there would be a barrier of some kind marking the end of space.
A theory called "Big Bounce" proposes that the universe could collapse to the state where it began and then initiate another Big Bang, so in this way, the universe would last forever but would pass through phases of expansion (Big Bang) and contraction (Big Crunch).
Trillions of years in the future, long after Earth is destroyed, the universe will drift apart until galaxy and star formation ceases. Slowly, stars will fizzle out, turning night skies black. All lingering matter will be gobbled up by black holes until there's nothing left.
The universe encompasses everything in existence, from the smallest atom to the largest galaxy; since forming some 13.7 billion years ago in the Big Bang, it has been expanding and may be infinite in its scope.
The trite answer is that both space and time were created at the big bang about 14 billion years ago, so there is nothing beyond the universe. However, much of the universe exists beyond the observable universe, which is maybe about 90 billion light years across.
Big Freeze, Big Rip, Big Crunch, Bounce or vacuum decay? Steven Strogatz speaks with theoretical cosmologist Katie Mack about the five ways that scientists think the universe could come to an end.
The ultimate fate of an open universe is either universal heat death, a "Big Freeze" (not to be confused with heat death, despite seemingly similar name interpretation ; see §Theories about the end of the universe below), or a "Big Rip" – in particular dark energy, quintessence, and the Big Rip scenario – where the ...
Georges Lemaître published a paper in 1927 that proposed the universe started out as a singularity and that the Big Bang led to its expansion [source: Soter and Tyson]. According to Einstein's theory of relativity, time only came into being as that primordial singularity expanded toward its current size and shape.
Eventually, the entire contents of the universe will be crushed together into an impossibly tiny space – a singularity, like a reverse Big Bang. Different scientists give different estimates of when this contraction phase might begin. It could be billions of years away yet.
Many religious persons, including many scientists, hold that God created the universe and the various processes driving physical and biological evolution and that these processes then resulted in the creation of galaxies, our solar system, and life on Earth.
The Big Crunch
In this model, the expansion of the universe doesn't continue forever. After an undetermined amount of time (possibly trillions of years), if the average density of the universe was enough to stop the expansion, the universe would begin the process of collapsing in on itself.
Even though certain features of the universe seem to require the existence of a multiverse, nothing has been directly observed that suggests it actually exists. So far, the evidence supporting the idea of a multiverse is purely theoretical, and in some cases, philosophical.
By 1014 (100 trillion) years from now, star formation will end, leaving all stellar objects in the form of degenerate remnants. If protons do not decay, stellar-mass objects will disappear more slowly, making this era last longer.
Memory Effect
The vacuum of general relativity may provide a memory matrix that preserves this information in the universe, beyond the black hole's demise. This memory effect makes sense when you think of Compère's picture of spacetime as a crystal.
Einstein's general theory of relativity predicts that time ends at moments called singularities, such as when matter reaches the center of a black hole or the universe collapses in a “big crunch.” Yet the theory also predicts that singularities are physically impossible.
It is impossible to destroy and create matter. Thus, everything that has existed still exists, and everything that will exist already exists, just not in the state(s) it did or is going to. And even if time is infinite you would not be born again.
In the beginning, there was an infinitely dense, tiny ball of matter. Then, it all went bang, giving rise to the atoms, molecules, stars and galaxies we see today. Or at least, that's what we've been told by physicists for the past several decades.
Because space isn't curved they will never meet or drift away from each other. A flat universe could be infinite: imagine a 2D piece of paper that stretches out forever. But it could also be finite: imagine taking a piece of paper, making a cylinder and joining the ends to make a torus (doughnut) shape.
Roughly 1 trillion years from now, the last star will be born. In about 100 trillion years, the last light will go out. The bad news is that the universe is going to die a slow, aching, miserable death. The good news is that we won't be around to see it.
The known laws of physics suggest that by about 10100 (the No. 1 followed by 100 zeros) years from now, star birth will cease, galaxies will go dark, and even black holes will evaporate through a process known as Hawking radiation, leaving little more than simple subatomic particles and energy.
One grim possible outcome is a Big Rip, which would ultimately unravel all matter down to the atomic level—though not for billions of years or longer.
How do we exit the universe? We can't travel out of the universe, any more than we can travel through time. Both are happening in a "direction" that physics doesn't allow us to move. For a balloon, all the intrinsic curvature can be measured by an ant on its surface, and that's all physics needs.
The universe could shrink just enough to return to a state similar to its original conditions. Another Big Bang – also known as a 'Big Bounce' – could then occur which would create a new universe from the old one. This cyclical pattern of expansion and contraction would constantly collapse and remake the universe.
The term dark matter was coined in 1933 by Fritz Zwicky of the California Institute of Technology to describe the unseen matter that must dominate one feature of the universe—the Coma Galaxy Cluster.