Is the age of the Universe "boundless"?

[swampwiz]

I was reading this Quora post, and it seems to say that the late, great Stephen Hawking has proven this.

https://www.quora.com/Have-scientists-disproved-Stephen-Hawkings-theories-of-the-universe

His work in both areas has shown that time is boundless in both directions, both forwards and backwards, so the universe never had a “beginning” even though it was once super dense and it won’t have an “end” even though every atom in the universe will be iron and all the black holes will have dissolved.

 

[phinds]

Is the age of the Universe "boundless"?

According to the currently accepted theory of Cosmology, The Big Bang Theory, that is unknown, since that theory is silent on any "creation event" and what might have gone before the time when there MIGHT have been a creation event.

 

[PeterDonis]

Our current best model of the universe says that it will continue expanding forever, so it is "boundless" in the future. However, as @phinds says, our best current model does not make a claim one way or the other about whether it has a finite age to the past or whether it has always existed. That is still an open area of research.

 

[PeterDonis]

Note, btw, that Hawking's actual proposal for a universe being "boundless" in the past, which was called the "no boundary" proposal, was not that the universe had existed for an infinite time in the past, but that the spacetime geometry of the very early universe was such that "time" had no meaning there and there was no starting boundary. Basically, instead of the geometry of the universe either extending infinitely into the past or having an "edge" at an initial singularity, it would be more like a hemisphere joined to an expanding cone, with the join being something like the big bang (or possibly the start of inflation). The "expanding cone" part is the part which can be viewed as a conventional expanding universe. The "hemisphere" part is the "no boundary" part, where "time" is not a meaningful concept--it doesn't extend infinitely into the past (since the hemisphere is finite), but it also has no boundary (since the hemisphere has no edge anywhere).

AFAIK this proposal is not currently considered a contender for a valid model of the universe. But I'm not familiar with the details of why it is not.

 

[rootone]

Erik Verlinde has this to say.