Does this explain what generates gravity?

[Bonsai]

We currently do not know how to define the ‘outer edge’ of the cosmos, but I would say it’s where light goes and matter follows.

 

[Galu]

There is no proof btw that the universe is infinite. If it started 13.8 billion yrs ago then it can’t be.

I should make it clear that the Universe being flat tells us nothing about the size of the Universe.

The Universe is infinite in the sense that it is not a closed ball, or more accurately, positively curved.

We know the Universe isn't infinitely old. Light from the Big Bang has had only 13.8 billion years to travel.

 

[Galu]

All agree? ;-D

First we had the Flat Earthers.

Now we have the Flat Universers!

 

[system7]

All baffling stuff. The Torus or Donut is apparently one of 18 flat shapes that can exist in 4D according to mathematicians.

We have discussed the mysteries of Gaussian Curvature before. Somehow if you look far enough with a lot of these flat shapes, you might see the back of your head.

Or come back to where you started from. So us ants can tell something about what we live on by crawling around and doing observations.

https://www.scientificamerican.com/article/how-many-holes-does-the-universe-have/

But it answered @Bonsai in his previous musings about the matter distribution within the +300,000 year Cosmic Microwave Background radius:

Cosmologists collect similar clues to determine the shape of the universe. They could send a spaceship out to traverse the cosmos. Instead they peer into the night sky and examine traces of the oldest light that reaches us from the depths of the cosmos. This radiation was created around 300,000 years after the big bang. Although photons had existed even before that, matter was so densely packed into what was then a small universe that the light quanta had no chance of traveling freely. Eventually, however, the universe cooled down to such an extent that it became transparent. The photons were able to spread freely through space—and still do today.

Matter all the way back to the CMB and beyond!

I downloaded the (old) Grisha Perelman 2008 paper, and it was totally beyond me. I think cutting the grass will be a better use of my time today.