Is Gravity Getting Weaker?

How do we know that G the gravitational constant has always had the same value?Since the universe is expanding isn't it possible that G is getting smaller and smaller? (for example)
- roxana

If G was changing, but all the other fundamental constants were not, then we could put that changing G into the calculations of how gravity made matter cluster together to form galaxies. The current clustering pattern, however, fits nicely with the one predicted assuming that G hasn't changed. So it would be very surprising to find that G had been somehow changing but covering that up.

Mike W.

We can also see high red-shift galactic evolution 12 billion years ago.   The early galaxies are evolving the same way as our nearby ones.   Any change in G would show some differences..

LeeH

 

(published on 12/15/2015)