Interesting article. I always love this kind of mind-boggling cosmic mystery.
NOTE: The article itself is sound, but the headline is not strictly accurate. We can see objects that are that are currently 46.1 billion light years away. Those two statements are not identical. We are seeing them as they were long ago, when they were no more than 13-point-something billion light years away. Two crucial things have happened since they emitted that light: (1) they and we have have moved away from one another at approximately the speed of light; (2) the universe, space itself, has expanded for various reasons touched upon in the article. (And we have fairly recently calculated – in the past quarter century or so – that the expansion of the universe is accelerating, which surprised many astrophysicists.)
That’s not so confusing, but a truly mystifying phenomenon is this: “The Universe Is Disappearing, And There’s Nothing We Can Do To Stop It.” How can that be? Because objects are moving away from us at an apparent speed faster than the speed of light. How can that be? It’s that pesky expansion again. The Hubble Constant (as recalculated since Hubble’s time) suggests that once distant objects are approximately 4,200 megaparsecs away (about 13.7 billion light years), two galaxies will separate faster than the speed of light.
In theory, if you could wait an infinitely long time, the night skies would be empty of any objects not gravitationally attached to us. (Well, I’m assuming that the life of the universe itself is infinite, which is probably not accurate, and I’m ignoring the fact that there will be no “us” then anyway, as our Sun will have burned out in some five billion years, which is just a brief blip of time in cosmological terms. Heavy stuff, dude.)
While I can’t predict with any certainty that we will still be around in 5 billion years when our sun expands to envelope the Earth, if we are I am fairly confident we will not have trouble surviving that event. Whether we end up relocating elsewhere in the solar system, other solar systems, or to envelope the whole galaxy our level of technology will probably be enough to let us relocate the Earth. Given enough lead time, a “gravity tractor” could slowly increase the size of the earth’s orbit. The question is if we are still around, what will “we” be? I am not sure we would be at all recognizable to ourselves.
The kind of forecast is (of course) totally beyond our ability to conceive. How much change occurs over the course of five billion years? Well, we can’t do five billion at all, because five billion years AGO, there was no Earth to compare to, but we can do four billion, which is when the most primitive life-forms emerged. Look at the difference between them and us, and then try to imagine the difference between us and whatever form of life will exist when that amount of change happens again. It boggles, but also thrills and engages, our minds.
Ethan has it right. And entropy death is in the Universe’s future if it keeps expanding.