The matter doesn't have to be destroyed, just dispersed with trajectories that prevent it from ever meeting again (luckily it has infinite space to do this in).

As far as we know, all the energy/matter came into existence with the creation of space-time. If this happened again, would that be a different universe? I suppose how that's how I was viewing it. One universe consisting of a certain amount of matter/energy from it's initiation, and that another one doesn't/couldn't/won't happen(?) inside another.

Another thing to consider is that space time didn't exist until the big bang, so it can't really be said to be a time-probable event. As far as we know, time didn't exist to lead up to it happening, so it might not really be applicable to apply it to happening "again" given enough time...because it includes/created/IS time.

You're right about that. I guess I'm assuming that black holes aren't infinite -- or rather, that nothing is infinite, which is odd since I'm assuming the universe is infinite in this question.

I see what you mean.

On a side note -- this seems pretty interesting to me.

If our universe was really infinite, the night sky would be completely white. :usehead:

http://memecrunch.com/meme/LEF/neature-walk/image.png

Only if it was infinitely old as well as infinitely large.

Yeah, I used infinite there to describe both time and size.

But..but...

If it was infinitely old, then all the stars would have died, and their light long since passed us an infinitely long time ago....so it could just as equally be all black(?)

Also, the infinite space would also have to consist of infinite matter in infinite directions to form the infinite stars/galaxies for complete coverage.........

http://25.media.tumblr.com/tumblr_ls...7nhuo1_500.gif

Goddamn, There's too many buts!

Fuck, I got busy with finals and never even checked back on this thread. Way too much to respond too, but bless you guys for an interesting discussion. And I've only gotten through the first two pages so far.

A couple things I just wanted to throw out real quick before I get back to studying for my epistemology final:
Tore's explanation of my original intention was spot-on, better than I said it.
I also wasn't talking about this universe necessarily. Infinity is important for the original point, but...
I am not willing to say that our universe is not infinitely old. It is certainly not infinite in size. But I don't think the universe is necessarily like the ray Neo described, because we didn't begin at the singularity. That's just the oldest thing that we can tell happened, because of the expanding galaxy. We almost definitely were a singularity, but I don't think I'm incorrect in saying that we could have been something before that.
I also don't think the universe should be compared to the numbers on the line Tore was talking about. Infinite time isn't the same as infinite numbers. But I'm not firm on this.

The rest that I've read so far I think I can be on board with.

Infinity is a notion of mathematics, no such thing has been observed. All we know the Universe is finite and expanding. But everything that has a beginning has an end. So there.

What I'm saying is I don't think that our universe necessarily did have a beginning, though. Infinity couldn't be observed, could it? You seem like you may know what you're talking about so I'll defer to you.

There was a beginning, the Big Bang, contemporary science agrees on that. Space and time were created at that very moment, there was no such thing as space and time before (there might have been something else but we have no way of knowing). Outside that I've no idea :)

What about M-theory?

In my honest opinion, M-theory is total BS.

Your veiws on this universe sounds like the model of the hypothetical universe you posed in your first post.

But you can see where not all of contemporary science agrees, because m-theory does have a fairly strong group of supporters.

Well I definitely don't think the universe is infinitely big, and I only say that we don't know if the universe necessarily had a beginning.

They live in imaginary world. Science must rely on evidence, otherwise it's not science.

Oh come on, you're being a little hyperbolic.

Nice math pun. While we are on the subject of math, maybe vktr is right. I think one of the problems with quantum mechanicist is their reliance on higher math like Probablity and Statics. There is a difference between fact gathering from observing and predicting something on paper based on formulae.

Of course :) But have you read this book by Lee Smolin?

http://upload.wikimedia.org/wikipedi...Book-Cover.jpg

The Trouble With Physics: The Rise of String Theory, The Fall of a Science, and What Comes Next

Scroll down that page and look at the review by Peter Shor.

String theorists: We've got the Standard Model, and it works great, but it doesn't include gravity, and it doesn't explain lots of other stuff, like why all the elementary particles have the masses they do. We need a new, broader theory.

Nature: Here's a great new theory I can sell you. It combines quantum field theory and gravity, and there's only one adjustable parameter in it, so all you have to do is find the right value of that parameter, and the Standard Model will pop right out.

String theorists: We'll take it.

String theorists (some time later): Wait a minute, Nature, our new theory won't fit into our driveway. String theory has ten dimensions, and our driveway only has four.

Nature: I can sell you a Calabi-Yau manifold. These are really neat gadgets, and they'll fold up string theory into four dimensions, no problem.

String theorists: We'll take one of those as well, please.

Nature: Happy to help.

String theorists (some time later): Wait a minute, Nature, there's too many different ways to fold our Calabi-Yao manifold up. And it keeps trying to come unfolded. And string theory is only compatible with a negative cosmological constant, and we own a positive one.

Nature: No problem. Just let me tie this Calabi-Yao manifold up with some strings and branes, and maybe a little duct tape, and you'll be all set.

String theorists: But our beautiful new theory is so ugly now!

Nature: Ah! But the Anthropic Principle says that all the best theories are ugly.

String theorists: It does?

Nature: It does. And once you make it the fashion to be ugly, you'll ensure that other theories will never beat you in beauty contests.

String theorists: Hooray! Hooray! Look at our beautiful new theory.

^Haha, haven't read it but I'm intrigued.

-Head explodes-

.... Yes? ._.

Sorry to bump an old thread but this fits the question.

Hints of hydrothermal activity on floor of Enceladus

no.

lol

/thread

Possible? Yes. Likely? No.

How do you define something? I feel like a lot of things could only happen once, depending on what kind of answer your willing to accept.

-Do you really think there are humans anywhere else? or any of the living thing on this planet? How about diseases?

I would define humans as Homo sapiens which is a loosely defined branch from a certain lineage that we can trace back to the earliest life forms on planet earth. You could have something that looked like humans on other planets, but they wouldn't be humans, because they would have no biological ties to our particular lineage.

But natural selection tends to make similar things over and over again in similar environments. Take hair for example. You can find hair on the butt of a bumblebee, but its evolutionary origin is very different from the hair on your head. Still, hair-like structures can be useful in many different ways and so has evolved independently several times.

Similarly, if the traits and collections of traits that make us human would also be useful elsewhere, it seems reasonable to expect similar traits would evolve on different planets.