Does the UNIVERSE have a boundary or OUTER LIMIT?

can you explain this a little better please. I'm not following it.

Hitchhiker has not posted in these fora in more than nine years. I suspect you won't be getting an answer.

In what medium does the balloon float?

That's a good question? If our universe is finite, like the balloon analogy suggests, what is outside our universe? I'd love to hear some physicists ideas on that. Does anyone have Stephen Hawking's email address?

I Googled "what's outside the universe" & read some interesting articles on geek.com and askamathematician.com

Some of the answers were:
1. nothing, our universe is all that there is (even though its finite)
2. Our universe is infinite (in which case there are major flaws with the balloon analogy)
Interesting quote: "If the universe is infinite, it would also contain an infinite amount of matter. In this case, literally every possible arrangement of matter is present an infinite number of times. There are an infinite number of Earths out there, if we look far enough afield, some drastically different from ours, some virtually identical, some literally identical. Actually, there would be an infinite number of every one of the infinite possible Earths. As to what’s outside this universe, well, there’s obviously nothing beyond an infinite border." Mind boggling.
3."then there are the multiverse explanations. These postulate that the universe split off after the Big Bang into everything from bubbles to sheets. Our universe is just one of many, possibly a finite number or possibly infinite. In this conception, what’s “outside” our universe is simply another universe. It could have identical physical laws to our own home, or have completely different ones. Everything from gravity to the strong nuclear force could be different, leading to a reality that could behave differently in fundamental ways"

-But then your question still has relevance; what medium fills the space between these universes?

Cosmologists have the best jobs. They get paid to sit around and think about this crazy stuff. It makes me realize how much my job sucks. Sorry for the long reply.

That's okay Jpsy. It was a good one.

What about an infinite number of Jpsys providing that exact reply to an infinite number of spendiuses who have just had porridge and a banana for breakfast at an infinite number of siderial times.

Perhaps cosmologists ought to apologise for stealing candy off taxpayers.

But what if the furthest stars are travelling away from us so fast in the expanding universe that their light is red-shifted into the invisible spectrum and we can't therefore see them?

Equus has not posted in years and years. I suspect you won't be getting an answer to your silly question.

Now I come to think of it, I read a short article by Isaac Asimov or Arthur C. Clarke some years ago in which he said something like- "If the universe wasn't expanding, the night sky would be a dazzling white sheet composed of stars with no black spaces between them and we'd all be dead with the heat given off by all those countless stars."

i think our technological programs should concentrate on traveling space in the speed of light years. may be this will works with black holes.

it is theorized that there is edge of universe and that edge is "no space and time". But just imagin that What is "no time and space zone"? Its the most simple answer of most complicated question, does the universe has some boundry?