Black holes/wormholes

[Nev]

See, deez, this is exactly what I meant by that "super genius"-comment on the other thread. It's quite a fucking feat to even remember stuff like this, let alone to have even the slightest comprehension of it!

[BlackWatch]

Not to mention recall it on demand in any given situation and apply it appropriately. I'm pretty sure if we don't watch him carefully he will become SkyNet.

[Dutch90]

Not necessarily...I've read theories about multiple universes...so ours dies, but it contributes to the existence of other ones.

Also watched an interesting show where physicists discussed that the end of our universe would return it to its original quantum state. Thus...another random occurrence such as the Big Bang (collision of virtual particles that deez discusses above) would create a new Big Bang and new universe (if I remember this correctly).

Then there is the oscillating universe idea...that eventually, the universe will collapse on itself (the Big Crunch) only to explode again (Big Bang).

Does this mean the universe isn't infinite? I mean, if it can collapse into itself, that means there has to be some limit to its scope. Infinity would make a total collapse impossible, right?

[deezelboy]

Yeah.

We don't know whether the universe has finite or infinite volume yet.  If it has a finite volume, it will at some point start collapsing inwards, towards its centre of gravity.  If it has an infinite volume, it keeps expanding forever.  All we know at the moment is that it's expansion is accelerating, with dark energy being the hypothesis to explain this acceleration.

[BlackWatch]

At the risk of not being able to comprehend the answer I'm going to ask anyway: what is dark energy? I've heard of dark matter but not dark energy.

[Neltharion]

Its a theory pretty much, its what holds all matter together apparently.

Ask the Internet, he knows all!

[Dutch90]

Yeah.

We don't know whether the universe has finite or infinite volume yet.  If it has a finite volume, it will at some point start collapsing inwards, towards its centre of gravity.  If it has an infinite volume, it keeps expanding forever.  All we know at the moment is that it's expansion is accelerating, with dark energy being the hypothesis to explain this acceleration.

So if it's infinite, that means there's also an infinite number of planets, correct? And if that is so, the possibilities of what's on these planets would also be, well, infinite.

This is going to sound ridiculous, but if the above is true it basically means that every fictional world, character, etc ever conceived by man should actually exist somewhere in the universe, right? I'm getting some cool Kingdom Hearts-like fantasies here.

Mind you, this isn't some actual scientific theory, this is just me brain-farting

[BlackWatch]

That's an interesting notion Dutch. As soon as they invent faster-than-light travel I'm off to find Risa.

[SiL]

So if it's infinite, that means there's also an infinite number of planets, correct?

From my understanding on the matter, not in the least. Infinite volume just means it has a large capacity, not that said capacity is full, or ever would be. Even if the volume of space is infinite, doesn't mean the quantity of matter within it is.

It's a common brain fart, and that's what I've scraped together reading conversations revolving around such. May be wrong

[SM]

Can I quote Douglas Adams, or would that be a bit too obvious?

[Neltharion]

Quote him.

[SM]

Right.  Ahem...

"It is known that there is an infinite number of worlds, but that not every one is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so if every planet in the Universe has a populations of zero then the entire population of the Universe must also be zero, and any people you may actually meet from time to time are merely the products of a deranged imagination."

[deezelboy]

At the risk of not being able to comprehend the answer I'm going to ask anyway: what is dark energy?

It's a hypothetical form of energy that exists as a consequence of space being empty, and exerts a negative pressure.  Basically, while gravity attracts, dark energy repels. 

So if it's infinite, that means there's also an infinite number of planets, correct? And if that is so, the possibilities of what's on these planets would also be, well, infinite.

In our obervable universe, no, for the reasons SiL gave.  Our observable universe contains 10⁸⁰ atoms, so while it's volume may be infinite, there's a finite amount of 'stuff' contained within it.

But outside our observable universe - maybe! 

The standard model of the Big Bang theorises a period of inflation, where space expanded at an exponential rate, at about 10^-36 seconds after the Big Bang itself.  As a result of this, our observable universe is but an infinitessimal part of the overall Universe (and becoming ever more infinitesimal if inflation is eternal).

Max Tegmark was interested in the idea of how far you'd have to travel to come to an identical universe to ours - one with an identical planet Earth with identical me's and you's, a carbon copy of our own.  He came up with a figure of 10¹⁰¹²⁰ metres.  For contrast, the diameter of our observable universe is 10²⁶ meters.

But essentially, if the inflationary model is correct, there are a huge number of universes identical to our own, and a much huger number of universes that aren't. 

So on the basis of probability, yes, provided a fictional world can arise through natural processes it is probable to exist at some point in the wider Universe, and likely that there will be multiple copies of it as well!

It's really one of the biggest mindfucks cosmology's come up with IMHO.  It does feel weird looking up into the night sky and realising that 10¹⁰¹²⁰ metres away there's another me, doing exactly the same thing and thinking exactly the same thoughts.

[Neltharion]

I really should of taken Physics cause this stuff is freaking awesome.

[BlackWatch]

I took Physics in high school but we never discussed any abstract or theoretical concepts like this. It was all by-the-book learning.

I've probably learned more by reading deez's posts than from my high school teacher. More interesting at any rate!