Thanks for this reply. I guess I now understand what people mean by "space is expanding".
If I understand correctly, space is what supports matter? Like a table supports dishes for instance (well, except that space is also "inside" particules) — and so if the table grows, the dishes don't.
I never actually even thought of what "space" means before. I thought that when we talked about space, matter was included in that (in the sense that quarks or whatever is the smallest — known? — particle take some "space" ; they're not points that can't be measured — or are they? ^^').
Anyway, it sparkled back an old interest of mine for astrophysics (well, I read one book from Hubert Reeves when I was a kid — and loved it).
Thanks again :)
(oh, as an added bonus: I guess we have no idea _why_ space is expanding, right? Because, I mean, it's a bit mind boggling...)
Edit: to be a bit clearer; I thought space was just void that "always" existed and extended indefinitely. Like, there was nothing except a small point with all the energy in the universe ; "everywhere" else a bit nothingness. Then, bim, the big bang, and matter was just booming away and making stars and planets and then galaxies and all that was just floating in this void/nothingness that was always there, never changing, still extending indefinitely. And that was why we were saying the universe was expanding — because galaxies were still speeding away from each others due to the big bang ; like an explosion with no friction perpetuing indefinitely.
Now I guess I'm really confused about what "space" is...
Quarks and electrons act like they're actually points. Nobody can be totally sure, but the standard math says they are, and nobody has managed to smash them apart into something smaller or measure them as anything other than "smaller than anything we can measure." They might be small loops of energy instead (this is part of string theory), but if they are, they'd be so small it would be beyond known science to prove it. It's easier to prove something has a size (by measuring it) than to prove the opposite. Every instrument has some margin of error, so you'd never be able to exclude there being some size.
The weird thing about the Big Bang is that it's really all of space that banged, and to a first approximation, space and time as we know it didn't exist before a singularity at the beginning of the expansion. It's very possible that's wrong (there may have been a "parent universe" or a "big bounce") but to a first approximation it seems to be that there may not have been a "before" the Big Bang.
If I understand correctly, space is what supports matter? Like a table supports dishes for instance (well, except that space is also "inside" particules) — and so if the table grows, the dishes don't.
I never actually even thought of what "space" means before. I thought that when we talked about space, matter was included in that (in the sense that quarks or whatever is the smallest — known? — particle take some "space" ; they're not points that can't be measured — or are they? ^^').
Anyway, it sparkled back an old interest of mine for astrophysics (well, I read one book from Hubert Reeves when I was a kid — and loved it).
Thanks again :)
(oh, as an added bonus: I guess we have no idea _why_ space is expanding, right? Because, I mean, it's a bit mind boggling...)
Edit: to be a bit clearer; I thought space was just void that "always" existed and extended indefinitely. Like, there was nothing except a small point with all the energy in the universe ; "everywhere" else a bit nothingness. Then, bim, the big bang, and matter was just booming away and making stars and planets and then galaxies and all that was just floating in this void/nothingness that was always there, never changing, still extending indefinitely. And that was why we were saying the universe was expanding — because galaxies were still speeding away from each others due to the big bang ; like an explosion with no friction perpetuing indefinitely. Now I guess I'm really confused about what "space" is...