Happy Astronaut

Can We Outrun Dark Energy In The Race To See The Universe?

“It’s always possible, and we must always keep this possibility in mind, that something is wrong with our current understanding. Perhaps our measurements are biased and have led us to an incorrect conclusion, but that would require an enormous number of independent lines of evidence all being biased in the same way. Perhaps we’ve got the laws of gravity wrong; perhaps we live in a very special and unusual region of the Universe that’s causing us to wrongly conclude that dark energy exists; perhaps there’s a novel force or interaction that exists that we simply haven’t properly identified.

In science, however, we base our conclusions on the full suite of data and evidence we have at our disposal, keeping in mind that they may change over time as we gain new and better information. The expansion rate is changing over time in a way that requires dark energy as the dominant component in our Universe, and dark energy is consistent with it being a cosmological constant: its energy density doesn’t appear to change with time. Unless dark energy reveals itself as something different or we find a short-cut through space, the majority of the observable Universe is forever beyond our reach already.”

Right now, if we left at the speed of light, we could catch up to the galaxies that are presently 18 billion light-years away from us, but not the ones that are any further. That is, assuming that we’re correct in our assessments about space travel’s limitations and that dark energy is what we think it is: a cosmological constant.