How ‘heat death’ will destroy the universe | Katie Mack | Big Think

How ‘heat death’ will destroy the universe
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The expansion of the universe is accelerating as the force of dark energy wins out over the pull of all the universe's collective gravity.

As every object in space moves farther and farther away from all other objects in space, the universe will reach a state of maximum entropy, and 'heat death' will ensue. As astrophysicist Dr. Katie Mack points out, heat death is not actually a hot phenomenon—it's also known as the "Big Freeze."

Around 100 billion years from now, the universe will have expanded so much that distant galaxies won't be visible from Earth, even with high-powered telescopes. Stars will disappear in a trillion years and new stars will no longer form. The 'good' news is that humans probably won't be around to witness the machine as it breaks down and dies.
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KATIE MACK:

Dr Katherine (Katie) Mack is a theoretical astrophysicist and assistant professor of physics at North Carolina State University. Her research has focused on dark matter, the early universe, galaxy formation, black holes, cosmic strings, and the ultimate fate of the cosmos. Dr. Mack's latest book, "The End of Everything (Astrophysically Speaking)" discusses five universe-ending possibilities proposed by cosmologists and what that grand finale would look like.

You can read Dr. Mack's latest book "The End of Everything (Astrophysically Speaking)" at http://amzn.to/3aEwsUx
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TRANSCRIPT:

KATIE MACK: When we look out into the night sky, we see distant galaxies are moving away from us. They're also moving away from each other and that's just what happens when all of space is getting bigger.

Everything is moving away from everything else. We can see the expansion carried out in the past—you know, it's carrying it out now—and we can extrapolate to the future and say it really looks like that expansion is going to continue forever.

As that process continues, everything is decaying so much that all that's left is the waste heat of everything that ever existed in the universe. So, you end up with a universe that's just very cold, and dark, and empty, and expanding all the time. That's the most accepted theory for the end of the universe.

My name is Katie Mack. I'm an assistant professor of physics at North Carolina State University and my book is called "The End of Everything (Astrophysically Speaking)." I thought it would be fun to talk about the far future of the universe. I find the fact that you can write down an equation and tweak a term and then the universe is destroyed... I find that delightful.

I study cosmology, which is the study of the universe from beginning to end, from the largest to the smallest scales. Most of the time in cosmology and physics, everything changes on very short timescales; everything's very orderly. And there's something kind of amazing about the idea of just big, destructive forces. The main observation that we have that tells us about the future evolution of the universe is the expansion of the universe.

When we look at the expansion of the universe, we see that the expansion of the universe is actually speeding up. And, this is very, very strange.

It should be slowing down because there's that immediate kick of the Big Bang. And then all of the stuff in the universe has gravity; all that gravity's going to be pulling back. It should be putting the brakes on that cosmic expansion.

In the late 1990s, astronomers measured the expansion of the universe and found, actually, it's not slowing down at all, it's speeding up. When that was discovered, we gave it a name. Something is making the universe expand faster. Whatever that something is, we're calling it dark energy. And one of the leading ideas for what dark energy is is actually an old idea from Albert Einstein which is called the cosmological constant.

His idea was that there's just some inherent stretchiness in space, that space has this tendency to expand just built into it. The reason that would cause the expansion to accelerate is that, in the past, there was a lot of dense matter and not that much space because the universe was smaller in the past, but now there's so much empty space that this little bit of expansiveness in every piece of empty space is starting to win out over the pull of the gravity of everything.

And so, the expansion is speeding up because now there's so much empty space that the cosmological constant is kind of taking over. If all we have in the...

Read the full transcript at https://bigthink.com/videos/heat-death-universe