effects of intelligence on the universe

[speedfreek]

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Is it possible we could point a beam of light at a distant galaxy, and it never gets there due to the space in between expanding? Either from our frame of reference or theirs?

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Yep, this sort of thing can happen. If I travel sufficiently far away from the earth (in an accelerating universe), I won't be able to get back to earth or even signal back to earth.

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In addition, this is already happening. We don't have to point a beam of light at distant galaxy, our galaxy is already sending light towards distant galaxies that will never reach them (i.e. they will never see our galaxy as it is now, they can only see our galaxy as it was when the apparent speed of recession between us and them was below that of light).

That is unless the hubble constant changes over time (we have some evidence this has happened in the past). Simply put, if the expansion of space ever slows down enough, our light will then be able to catch up with them again!

We have some observations that lead us to conclude that the expansion decelerated early in the history of the universe, and then started accelerating more recently. We can see over a thousand galaxies that are receding from us faster than light, but when their light was emitted the hubble constant was different, (and thus so was the hubble distance - the threshold where we cannot see objects anymore) which has allowed their light to slip into our observable universe.