Would it be possible with powerful enough telescopes to actually see the Milky Way earlier in its cosmic history? And track its history from its birth to the galaxy we see in the sky now? I guess what I’m saying is could we, given powerful enough instruments and a little spare time, watch the whole history of the universe unfold from its birth until the present (whatever the present means in this context)? Is the light still all out there to enable this?
IAN Astronomer but surely that light is now going away from us. If the universe is spherical I suppose we might get it on the second pass, like a tsunami wave, but that seems unlikely.
Yes, but we would need faster then light travel to get far enough away to observe the light from back then, or somehow find light from it somehow ‘frozen’ (which I believe we are able to do).
As I understand it, if the Universe keeps expanding, the light from our own galaxy will never reach us again, because it will keep going away from us into the new space created by the expansion of the Universe. It will eventually become so diffuse as to be completely indistinguishable from the background radiation, which will asymptotically trend towards absolute zero. Oh, and apparently all protons will eventually decay as well, meaning there won’t be any atoms anymore.
That, however, will not necessarily discharge a student loan debt.
We can already see the primordial light released after the photon decoupling which happened 300,000 years after the Big Bang.
What we can’t see (yet) is the earlier stuff because the Universe was opaque. So to measure that we need gravity wave detectors in space away from Earth. A detector is simple enough: an L shaped rod a mile long each way with movements of the ends being measured.
I think I get it, the light from the early Milky Way would be traveling away from us whereas the light from these early formations is coming towards us. And to catch the later history of such formations we’d need to catch up with light that has already passed us by.
Do scientists have any idea of what the universe looks like now rather than the patchwork picture of what it looked like millions or billions of years ago? Or doesn’t that question make sense in cosmic terms?
What the Universe looks like now is what we see in our general neighborhood. Our location isn’t special; other parts of the Universe look much like we do.
Sort of. They can predict how it evolves from the state we see it in now, so we can have a broad picture of what it looks like ‘now’ based on what it looks like to us from the light it emitted time ago.
Since light is affected by gravity, presumably some of it has been bent towards us from a variety of distances away (AKA lensing). I just doubt that we have detectors of sufficient size/precision as to be able to make heads or tails of the grand majority of the detail present in the narrowest sections of the lensing. Though, as I understand it, we do use lensing to help us understand more about objects which are behind the lens.
While it is possible to lens light directly back to its source, it’s quite difficult, and requires a very close brush with a black hole. In fact, this is one of the ways astronomers look for black holes, by looking for objects in the sky which have exactly the same spectrum as the Sun (none have yet been found this way, but it has been attempted).