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[Friday]

Large Hadron Collider generates a "mini Big Bang"

so more like a little bang, i mean hardly even a bang, more like a pfft

[Cthulhu-chan]

More of a scale-model bang replica.  A bang miniature?

Amazing that they'll even be able to make sense of that smear of trace lines.

[Classic]

I've never really understood the big bang. Or how you could have an expansion of space. I mean, I "know" that the way we move through time is variable... and I guess it makes sense (in that it makes physics models "simpler" and more self-contained) that gravity is the result of mass distorting space.
But...
...
Space expanding? That. I... Umm... help?

[NexAdruin]

I've never really understood the big bang. Or how you could have an expansion of space. I mean, I "know" that the way we move through time is variable... and I guess it makes sense (in that it makes physics models "simpler" and more self-contained) that gravity is the result of mass distorting space.
But...
...
Space expanding? That. I... Umm... help?

Space is like a 4-dimensional balloon, expanding outward as it inflates. In the world that we would see, anything outside the "edge" of the universe would be dark (no light or matter or energy has gotten there yet), so we say that space is expanding as the matter that started with the big bang moves outward.

Edit: if anyone knows better, feel free to correct me on this.

[Classic]

I guess my question is, why do we say "space" is expanding if the stuff (or we hope, lack thereof) outside of the expansion is not also space? I'd buy that we "can't know" because space is expanding at c or close to c.

[NexAdruin]

Space is expanding at c because the light traveling outward from the beginning explosion is what defines the edges.

When we say space, we just mean what's inside the balloon/bubble/however you want to picture it. I guess anything outside of that is just immaterial as it doesn't affect anything inside the edges. Anything outside of the edges is just nothingness. Less even than space (Space isn't actually a vacuum, but what's outside of it is).

My own understanding of all this is pretty flimsy, admittedly, but this is what I gather from conversations/books/etc.

[Büge]

There isn't anything outside of space. The closer you get to the edge, the more distorted space/time will get, like looking into the reflection of a doorknob. Except you won't notice it, because your perceptions will remain the same.

We know space is expanding because there's a barrier of microwave radiation that keeps our radio telescopes from measuring out past a certain distance. There's also the tendency for galaxies observed to be in the red spectrum, suggesting that they're moving away.

[NexAdruin]

I think what he's saying, though, is that there has to be something for space to be expanding into. Going with the balloon analogy, the balloon itself is surrounded by air and space. So what's surrounding spacetime?

[TA]

Heaven.

[NexAdruin]

Oh, you.

[Brentai]

If you believe that time is bound to within the confines of our expanding universe (and the math-I-don't-understand somehow suggests that it is), then going beyond the expanding light curtain means you will literally leave time.  That doesn't mean there's nothing beyond that, just that there's nothing that we are currently conceptually equipped to understand.  Also, you can't turn around and come back, because there is no longer an around to turn.

Yeah.

[McDohl]

I'm sorry, but I'm banking on Futurama, where everyone on the other side is wearing a cowboy hat.

[Cthulhu-chan]

Space-time IS the universe, so there isn't an "outside" to discuss.

[Royal☭]

I think I remember reading in a Brief History of Time that if you pick a direction in the Universe and travel for infinity time you'd arrive at where you started.  That's all I have to add.

[François]

The way I see it, you can never be outside of the universe, because wherever you are, there it is. You bring it with you. You expand it. You don't traverse its outer limit as much as you become its outer limit.

[Royal☭]

Like Minecraft.

[Classic]

Did not know about the microwaves.

Since I started asking these sophomoric questions, I've also started worrying about there being another space-time expansion event that could intersect with the known space-time expansion.

[Büge]

The way I see it, you can never be outside of the universe, because wherever you go, there you are.

[Cthulhu-chan]

Did not know about the microwaves.

Since I started asking these sophomoric questions, I've also started worrying about there being another space-time expansion event that could intersect with the known space-time expansion.

Last I heard, that might be possible, but you'd never know it.  Said event would expand into it's own bubble of spacetime, and would look like any old blackhole to us, at most.

[Catloaf]

I keep hearing shit about biocentrism.  Which basically says things like we're all inanimate objects when looked at from outside time, the observers are the ones creating the universe by observing it, and we could very well be experiencing time backwards and the big bang is actually the end of the universe.  Anyway, applying this school of thought, assuming that time does move forwards rather than backwards, couldn't the expansion of the universe be based on the number of and range of sight of observers?  Like it always goes a little bit further than we can see, and when we can see further, it goes further again.  But then again, biocentrism implies that there may be a separate universe for all individual observers and that would I'm the one making all of you exist and have horrible lives.  Sorry.  In my defense, you're all doing it to me as well.