any astrophysicists here?

[strvger]

just have a (probably) simple question that i've never seen an answer to. on the tv science channels and books i've read, the universe has been described as being finite... having a beginning and an end to it. now, i've also seen and read that at the center of black holes, a burned out star exists that has collapsed in on itself and has infinite density since even light cannot escape it's gravitational pull.

so my question: how can there be anything "infinite" in a "finite" universe?

thanks in advance for your explanation.

 

[BlueChariot]

Black holes are a horrifically complex topic, and I'm sure a true scientist could answer you more properly, but heres my thoughts:

The universe as we know it is considered infinite, yet it sort-of isn't. As a scientist would tell you the universe is currently expanding. Into what? I've no clue, would be nice to know. The universe is said to be in "Red Shift" when it is expanding, and in "Blue Shift" when contracting (which it is projexted and assumed to eventually start doing in a proposed cycle resulting in an eventual Big Bang). They can tell this because of examining light from distant galaxies.

As far as black holes are concerned, we are just now starting to makes the types of leaps in science as to better examine them and their behavior. It's been a while since I've read up on them so I can't comment much more than "it just sort of.. is".

I hope at least some of this is helpful, or at least something new you learned. lol

If you ant to learn some cool things on physics (and alot on theoretical physics) look up stuff by João Magueijo.

 

[Bennybooster]

The center of a black hole is actually a tear in the fabric of space, so getting sucked into a black hole is actually like falling down into a waterfall, only at light speed and you would be converted into pure energy.

It also is immeasurably small and immeasurably dense. So its not infinite, its just impossible to measure.

I am learning this exact subject in astronomy right now, so I still don't have a very high understanding of it all, but if you have anymore questions post up, ill try to answer. And I can get out my notes to, so I can give some better answers.

 

[pjtoledo]

Black holes are a horrifically complex topic, and I'm sure a true scientist could answer you more properly, but heres my thoughts:

The universe as we know it is considered infinite, yet it sort-of isn't. As a scientist would tell you the universe is currently expanding. Into what? I've no clue, would be nice to know. The universe is said to be in "Red Shift" when it is expanding, and in "Blue Shift" when contracting (which it is projexted and assumed to eventually start doing in a proposed cycle resulting in an eventual Big Bang). They can tell this because of examining light from distant galaxies.

As far as black holes are concerned, we are just now starting to makes the types of leaps in science as to better examine them and their behavior. It's been a while since I've read up on them so I can't comment much more than "it just sort of.. is".

I hope at least some of this is helpful, or at least something new you learned. lol

If you ant to learn some cool things on physics (and alot on theoretical physics) look up stuff by João Magueijo.

so, you're sayin' we are all riding along on a giant YO-YO?

BANG,, matter is flung out into whatever,, sooner or later the matter slows down as gravitational forces take over and everything reverses course and races back to the starting point only to get super squished and BANG! it all starts over again, and again, and again.

Wow, the universe is just one super sized bungie cord. who'da thunk it was as simple as that?



(way past my bedtime, must be dreaming this)

 

[colby450xc]

just have a (probably) simple question that i've never seen an answer to. on the tv science channels and books i've read, the universe has been described as being finite... having a beginning and an end to it. now, i've also seen and read that at the center of black holes, a burned out star exists that has collapsed in on itself and has infinite density since even light cannot escape it's gravitational pull.

so my question: how can there be anything "infinite" in a "finite" universe?

thanks in advance for your explanation.

Hell if I know, whenever I read or watch something about space they always claim that space is expanding constantly. Is that finite? I really don't think so...........

 

[BlueChariot]

so, you're sayin' we are all riding along on a giant YO-YO?

BANG,, matter is flung out into whatever,, sooner or later the matter slows down as gravitational forces take over and everything reverses course and races back to the starting point only to get super squished and BANG! it all starts over again, and again, and again.

Wow, the universe is just one super sized bungie cord. who'da thunk it was as simple as that?



(way past my bedtime, must be dreaming this)

That's the currently held theory. Going by the average, purely scienfitic point of view, the cycle would go Big Bang -> Red Shift -> Blue Shift -> Everything condensing, causing another Biug Bang.

 

[Captain Ledd]

I've always wonderd this:

If the images we see through telescopes at edges of our galaxy are from when the universe was just formed, how did they get that far out in the first place? And have the light just now reaching us? Did that matter travel faster than light? Also how come the universe is eerily similar distance (in astronomical scale) at all the "edges" around us? Doubtful that we're the center...

Infinite/finite my foot, I call shenanigans on all of it.

MOAR 5TUDI3S!

 

[BlueChariot]

I've always wonderd this:

If the images we see through telescopes at edges of our galaxy are from when the universe was just formed, how did they get that far out in the first place? And have the light just now reaching us? Did that matter travel faster than light? Also how come the universe is eerily similar distance (in astronomical scale) at all the "edges" around us? Doubtful that we're the center...

Infinite/finite my foot, I call shenanigans on all of it.

MOAR 5TUDI3S!

Light is indeed the fastest thing in the universe, so no, the matter couldn't of moved that fast, and light's speed is a constant (Although the VSL theory, which I find brilliant, challenges that).

Also, if you think about it, given the vast distances, the point at which the light was released from a galaxy moving away from us is not the same place it is when we see the light. Think of a bullet being fired backwards from a moving car.

Also, "edges" is a fancy word for "we can't see farther than this". So know one knows where the center is.

 

[LearjetMinako]

Light can only go so far. As the further the light source is moved away, the dimmer it becomes. Evently, the light source will be so far away that it longer will reach us. So thats a reason why the stars seem to be evenly spread around us. There are stars beyond what we see that exist, but the light can't reach us.

 

[fratermus]

Black holes do not have infinite density. Just an incredibly high density; enough mass jammed in there to have a great deal of gravity.

 

[fratermus]

Light is indeed the fastest thing in the universe, so no, the matter couldn't of moved that fast, and light's speed is a constant (Although the VSL theory, which I find brilliant, challenges that).

There are scenarios like transparent fluid media where light is slowed and things unaffected* by matter, like neutrinos, can at that point be traveling faster through the media than that light. But not faster than than the C constant.


* practically speaking

 

[Mutant Pony]

As in the "big bang theory" and expanding universe what they are talking about is the "known" universe. They just conveiniently forget the "known" part.
I looked it up a while ago as it perplexed me the same way. If you think of the universe as infinate, the big bang theory makes no sense at all. Although, when you add "known" to it, it makes perfect sense.
Actually the big bang theory is a better explanation for each galaxy. IMO.

 

[Scrambler82]

And with all that negative gravity the big U is still expanding.

 

[BlueChariot]

There are scenarios like transparent fluid media where light is slowed and things unaffected* by matter, like neutrinos, can at that point be traveling faster through the media than that light. But not faster than than the C constant.


* practically speaking

True, but theres very little of that for the light to pass through in space on it's way to our telelscopes, so I didn't bother mentioning it.

This thread makes me smile, I love physics but always hated the idea of studying it in school. lol

 

[88SXT]

meh, this is way more than i care to try to understand, im a mechanic not a scientist, i have a high school diploma and alot of OJT, not a doctorate and government grants for a fancy laboratory, if ya'll figure out how this applies to me, let me know, untill thn im gonna continue turning wrenches and getting covered in jet fuel and hyd fluid