GIF at 11!
While I was out learning how to manipulate the universe inside the Digistar 5 last week, a news story broke about how the universe is slowly dying. Astronomers are doing a survey of galaxies of all shapes and sizes in 21 wavelengths of light, and have discovered that the energy being produced by stars, nebulae, and galaxies in a surveyed portion of the cosmos is about half of what it was just two billion years ago.
Yes, you read that right: the energy emitted is MUCH less than it was in the past. (For reference, the universe is 13.7 billion years old, or thereabouts.) The team looked at more than 200,000 galaxies to come to their conclusion that the universe is settling back for long, quiet old age as it slowly fades away.
The news that the universe is riding off into the sunset (sort of), is not new news. It’s been on scientists’ minds since the 1990s, but this recent survey is the most detailed look at just how much it is fading and how widespread the dimming down is across the cosmos.
How Long Will It Take?
So, now that we know the universe is dying, the big question is, how long will it take to completely cool and die? The best answer I could find among several places that discuss the end-game of the universe puts it at quintillions of years from now. Between now and then, all the stars will eventually die, dimming out the galaxies. The clouds of gas and dust that make up stars (and planets) will be used up, leaving no building blocks for new stars. Some theorists suggest that there will be a time when only black holes will dominate the universe, making the end state of the cosmos a truly Dark Era.
So, the slowly cooling universe will outlive us all, and likely exist long after all in the cosmos is gone (or evolved to something else). But eventually, the cosmos will be cold and dead. It’s a tough scenario to imagine. But, it makes sense; all things must eventually cool down, slow down, and come to a halt. Even the universe.
The story of our dying universe reminds me of a great science fiction story by Isaac Asimov, called The Last Question. It explores this very idea, but through the eyes of a cosmic computer that continues to ask the same question throughout cosmic time: “How can the net amount of entropy of the universe be massively decreased?” (In other words, can the second law of thermodynamics be reversed? (It states that entropy always increases. Read more about it here.)
I won’t give away the answer, so go find the story for yourself and enjoy! Dr. Asimov created a wonderful thought experiment that goes right along with our newly expanded view of the universe’s impending (and far in the future) death.