The ultimate fate of the Universe PDF

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Astronomy related to cosmology...

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The ultimate fate of the Universe

The Big Rip: Dark energy dominates and eventually expansion becomes so fast that galaxies, stars, and finally atoms are ripped apart. The Big Crunch: The expansion of the Universe will eventually slow, stop, and then the Universe will begin contracting until it repeats the Big Bang in reverse. The Big Freeze (or Heat Death): The Universe will continue expanding as it is now. Stars will continue to form for a few trillion years, but eventually all the gas will be used up and all the stars will die without any new star formation. Black holes will continue to accrete any matter around (white dwarfs, black dwarfs, planets), until they are the only objects left in the Universe. After trillions of trillions of years, even the black holes can evaporate by quantum processes. The universe will be cold and dark and boring.

The ultimate fate of the Universe

The Big Rip: Dark energy dominates and eventually expansion becomes so fast that galaxies, stars, and finally atoms are ripped apart. The Big Crunch: The expansion of the Universe will eventually slow, stop, and then the Universe will begin contracting until it repeats the Big Bang in reverse.

The Big Freeze (or Heat Death): The Universe will continue expanding as it is now. Stars will continue to form for a few trillion years, but eventually all the gas will be used up and all the stars will die without any new star formation. Black holes will continue to accrete any matter around (white dwarfs, black dwarfs, planets), until they are the only objects left in the Universe. After trillions of trillions of years, even the black holes can evaporate by quantum processes. The universe will be cold and dark and boring.

The expansion of the Universe is accelerating The very distant supernovae were fainter than expected – this means the universe has expanded more than expected since their light was emitted billions of years ago. In other words, the expansion of the universe is accelerating – it is expanding faster and faster.

In order to explain the extreme uniformity of the CMB (it’s exactly the same temperature within millionths of a degree), there had to be a very early period of exponential inflation. This also helps to explain some aspects of quantum mechanics. Many cosmologists are also

particle physicists: the largest structures in the Universe can teach us about the tiniest particles in the Universe, and vice-versa....