PeterDonis's latest activity

No, that's not correct, as the bottom diagram of Figure 1 of Davis & Lineweaver shows. Our past light cone "now" covers a finite extent...

It isn't, and I never said it was. Go back and read what I said, carefully.

The initial singularity can't really be properly represented on a diagram whose horizontal axis is proper distance. In terms of proper...

No, that's not what I said. What I said is that our observable universe, in the limit as you go to the initial singularity, shrinks to a...

I'm not sure that's quite true: the particle horizon is lightlike, but I think the "funnel" boundary is intended to be timelike. I think...

Interpreting it charitably, it's only showing the observable universe, which is a finite patch of space at any given time and therefore...

Is not intended to be a precise representation of the actual model. You can sort of make heuristic sense of it by thinking of what it's...

Because when we construct a model of the universe using GR, under the assumption that it is dominated by matter and radiation at early...

Yes. Spacelike surfaces are moments in time, so the big bang singularity was not a place - apart from anything else it's in the past of...

Yes. The Big Bang singularity is a moment of time that is to the past of every event in the universe.

Gravity, of course, is not fictitious because the Riemann curvature is a tensor. But gravity is not the same thing as gravitational...

This is personal speculation and is off limits here. Thread will remain closed.

Thread closed for moderation.

If that's how you want to define "matter", sure. As I said in post #2, "matter" is a word. There is no one single thing in the actual...

He-3 does "take up room"; the fact that it is superfluid at low enough temperatures does not prevent it from occupying volume...