Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: bobdihi on 24/05/2024 16:16:56

Title: Universe related questions
Post by: bobdihi on 24/05/2024 16:16:56
Warning may contain stupid questions.

1. Does Universe has to meet some prerequisite before it can be considered a Universe?
2. Can we have a microscopic Universe?
3. Can there be a Universe withing a Universe?

Thx
Title: Re: Universe related questions
Post by: alancalverd on 24/05/2024 17:06:43
No
Yes
Yes

but mathematically, not as imagined by priests or philosophers
Title: Re: Universe related questions
Post by: paul cotter on 24/05/2024 17:48:59
I disagree, Alan, on #3. The universe is by definition "all that there is". So anything within is part of the universe. There could be partitions within the universe but they would not be universes. However such arguments are akin to "how many angels can dance on a pinhead"
Title: Re: Universe related questions
Post by: alancalverd on 24/05/2024 20:04:02
It all depends on the qualifying adjective. Without one, there is only one universe, i.e.  everything that exists, all the space it occupies, and all the space or whatever there may be outside the boundaries of everything that is.

But once you qualify it with "observable" or "effective", you can indeed have a small one inside a big one, for example all the stuff emanating from the Big Bang can be imagined to be inside the remnant of a bigger bang, and everything that can possibly affect the flea in my test tube is inside my laboratory.