According to the article “The End of Cosmology” in the March Scientific American, “evidence of the universe is disappearing as the universe expands.”
I guess that’s OK, as long as it doesn’t happen before my subscription runs out.
Edwin Hubble figured out not only that the universe is expanding, but that the speed at which an object recedes due to expansion of the universe is proportional to its distance. That is, an object twice as far away is expanding away from us twice as fast.
Thus, at some distance, there are already objects expanding away from us so fast that we will never ever see the light they emit. No form of radiation they emit will ever reach us. They have already become invisible. By the time our civilization became advanced enough to detect other galaxies, some of them have receded forever from view. We will forever be unable to detect that they ever existed in a younger universe.
At present (13.7 billion years), the “observable universe” still includes most of all matter in the universe, but at, say, 100 billion years, Earth (or its blackened residue) will see a local supergalaxy consisting of a merged Andromeda, Milky Way, and a few small neighboring galaxies in what we now call our Local Group. All else will have drifted from view, into the void of a black eternal night.
That boundary beyond which we can see nothing will be an “event horizon”, conceptually the same as the event horizon of a black hole, but with us on the inside, unable to see out. Cosmologists wryly conclude that energy within that event horizon will therefore be finite and limited — we have permanently lost contact with everything outside the expanding horizon. As the finite star population ages and winks out, the observable universe will turn cold and disappear, eventually collapsing into a black hole.
The whole cosmological cycle may last 100 trillion years. Just to be safe, I’m only renewing my subscription year by year.
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