Yes, it is a depressing topic to think about (although I don't know why, since we will all be dead by the time the Universe ends, if it does), but it is also an interesting one. I'd like to hear your opinions on this topic: Will it end? How will it end? A lot of the theories on Wikipedia require you to know about the different theories of the Universe's shape and how this affects how it may end, so I'd advise people who are interested in the topic to view the Wiki-page: Ultimate Fate of the Universe "The ultimate fate of the universe is a topic in physical cosmology. Many possible fates are predicted by rival scientific theories, including futures of both finite and infinite duration. Once the notion that the universe started with a Big Bang became accepted by a consensus of scientists, the ultimate fate of the universe became a valid cosmological question, one depending upon the physical properties of the mass/energy in the universe, its average density, and the rate of expansion." Map of the Universe. ly = Light-Year. Heat Death "The heat death is a possible final state of the universe, in which it has "run down" to a state of no thermodynamic free energy to sustain motion or life. In physical terms, it has reached maximum entropy." Big Rip "The Big Rip is a cosmological hypothesis first published in 2003, about the ultimate fate of the universe, in which the matter of the universe, from stars and galaxies to atoms and subatomic particles, is progressively torn apart by the expansion of the universe at a certain time in the future." Animation of a galaxy undergoing the Big Rip. Big Crunch "In physical cosmology, the big crunch is one possible scenario for the ultimate fate of the universe, in which the metric expansion of space eventually reverses and the universe recollapses, ultimately ending as a black hole singularity." The Big Crunch. All matter in our universe contracting into a singularity. Multiverse "The multiverse (or meta-universe) is the hypothetical set of multiple possible universes (including our universe) that together comprise all of reality. The different universes within the multiverse are sometimes called parallel universes or dimensions. The structure of the multiverse, the nature of each universe within it and the relationship between the various constituent universes, depend on the specific multiverse hypothesis considered." Drawing of parallel universes (or multiverses) lying on top of each other. False Vacuum "If the vacuum is not in its lowest energy state (a false vacuum), it could tunnel into a lower energy state. This is called the vacuum metastability event. This has the potential to fundamentally alter our universe; in more audacious scenarios even the various physical constants could have different values, severely affecting the foundations of matter, energy, and spacetime. It is also possible that all structures will be destroyed instantaneously, without any forewarning." So what are your thoughts on these theories? I mean, if you have anything else to add, your opinions on what could happen then go ahead and share them.