Question

We know the universe is expanding,but relative to what?

Answer 1

If we look at galaxies that are not part of our local group, you will always notice they they are accelerating away from the Milky Way. Also there is a "red shift" present, indicating that the galaxy is increasingly accelerating.

Answer 2

Right,
Does any observer sens this aacelerating؟

Answer 3

Hi, It has been a long time since I studied any physics so my answer might not be the best.
I think that we need to think about the question first and then the answer. Is it the right question? I can see that if we think of the universe as expanding away from a point that asking where that point is makes sense and I think this is your question. If however the universe is just changing scale (getting bigger) then the distance between any two points will be getting bigger and so for an observer at one of the points the other will aways appear to be moving away. The universe does not have to be expanding relative to one point.
I am not sure if this is the right answer but it may help you to think differently about the problem.

Answer 4

you are waiting for a response?

Answer 5

Hi hani, No, I just haven't moved off the page :) best wishes.

Answer 6

any way,
i dont know the is expanding relatve to what(not one piont)?

Answer 7

v
Velocity and acceleration are rates of change. I don't think they need to be relative to a point. Distance is measured from a point so it needs something to be relative to.

Answer 8

i'll think more,
ok!

Answer 9

Me too. Goodnight. best wishes.