Observable universe: expansion and light speed

[ninar]

a. Is it known if there are actually regions of space which would be far enough and expanding at a rate enough that light will never be able to reach us?

Or, is it possible to say that a boundary may exist in a way that, beyond it we can be sure that light will certainly not reach us?

b. Also, please correct me on this (mis)conceptions: the light we detect from very very far distances, it can be "pulled" from the accelerating expansion of the universe if that rate is faster than the speed of light?

c. Finally, the current accounted measure for "observable universe", to what extent does it recognize and distinguish the expansion rate of the universe / light speed?

S--S-S-Sorry if this is tedious to hear if its a repetitively emergent topic... if another thread matches my inquiries please link them to me :) Thanks

 

[lippyka]

!a. Yes, it is known that there are regions of space that are so far away and expanding so quickly that light will never be able to reach us. These regions are known as the "observable universe" and they encompass all the regions of space that we can see due to the finite speed of light. Beyond this boundary, light may never reach us.b. That is not correct. The light we detect from very far distances is simply light that has been traveling for a very long time, having emitted from distant stars or galaxies billions of years ago. The expansion of the universe does not affect the speed at which this light travels.c. The current measure for the "observable universe" takes into account the speed of light and the rate of expansion of the universe. It is estimated that the observable universe is approximately 93 billion light-years in diameter, meaning that light emitted from objects beyond this distance would take longer than the age of the universe to reach us.