Astronomical distances, light speed, and uncertainty

[longship]

2. Even if you have had astronomy and physics it's mind bending.

So don't feel like the Lone Ranger here. But let me attempt.

We have reasonable certainty that distant objects are still in existence because throughout our observations we see similar objects at different ages in their respective lifetimes. So we can infer that the mind numbingly distant objects would obey the same physical laws and evolution as we observe elsewhere.

Distances are problematic, too. The Big Bang occurred about 13.7 billion years ago. But since that happened the universe has gone through 13.7 billion years of expansion. So when one measures the distance to a galaxy 10 billion years distance, its actual distance now is much greater.

How big is the universe? It depends how one measures it. I don't recommend delving into this question unless you want a mind twisting answer. Here's one answer from Astronomy Cast

It's all fun, though.