"Black" holes and "White" holes

  • #26
Chronos
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A white hole is one possible solution to the Einstein field equations, as is a black hole. Mathematical possibilities, however, are not always realized in nature. We already have reason to believe GR is an incomplete description of gravity, and will remain so until we have a valid theory of quantum gravity - which is a possibility in the not so distant future. Once we unify quantum physics with GR many puzzles with things like black holes and white holes should be resolved. In the mean time we must rely on observational evidence to realize the distinction between reality and mathematical artifacts. The observational evidence favoring black holes as a valid solution to EFE is overwhelming. The evidence favoring white holes is virtually nonexistent. The prime directive in physics is a theory is nothing more than a hypothesis until until predictions made by that theory are confirmed by observational evidence.
 
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  • #27
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ok i know white holes are only theory so far but i was wondering if time could work in a different in the way than black holes has shown to be... like only lasting for a nano sec spewing out energy and matter then somehow shut off or run out of energy and matter for the nano sec?? or are they predicted to hang around as long as the cosmic vacuum cleaners do?????

:bugeye:
 
  • #28
Fervent Freyja
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\ I wonder why no one has ever tried to send a camera of some sort inside a black hole to actually see what happens before (or if) it's destroyed?.
The nearest black holes are thousands of light years away...
 
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  • #29
Chronos
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Yet we observe phenomena in various parts of the universe that cannot be accounted for by any known physics aside from black holes. The same cannot be said for white holes.
 
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  • #30
phinds
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That's mostly the theories I've read about, Praveena. I wonder why no one has ever tried to send a camera of some sort inside a black hole to actually see what happens before (or if) it's destroyed? Until we actually know what's inside, everything we say is nothing more than conjecture or speculation at this point.
What good would sending a camera in do? It can't come out again, nor can any information from it so what would be the point?

Also, the nearest known BH is tens of thousands of light years away so would take us hundreds thousands of thousands of years to get there.

There are other problems.

I don't think your camera idea works out too well.
 
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  • #31
Chronos
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  • #33
Chronos
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The short answer is nothing exits a black hole and nothing enters a white hole.
 
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  • #34
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You can't enclose anything infinite inside a finite volume.
Well, the 'depth' of a point is infinite.

The nearest black holes are thousands of light years away...
What good would sending a camera in do? It can't come out again, nor can any information from it so what would be the point?

Also, the nearest known BH is tens of thousands of light years away so would take us hundreds thousands of thousands of years to get there.

There are other problems.

I don't think your camera idea works out too well.
Party poopers with no sense of humor.

The short answer is nothing exits a black hole and nothing enters a white hole.
That depends. Are we talking about spacetime holes or humanoid holes?

I never heard of a 'white hole' beyond the biological realm before.
 
  • #35
phinds
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Party poopers with no sense of humor.
No, party poopers who poop on crackpot science
I never heard of a 'white hole' beyond the biological realm before.
I take it you know little about cosmology. It's an extraordinarily common term (in cosmology). Just for grins, I just Googled it. ALL of the two pages were referring to cosmological white holes and I'd be surprised if the next 10 were not as well. I think your sense that it is a biological term is a significantly minority view.
 
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  • #36
phinds
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Well, the 'depth' of a point is infinite.
No, the depth of a point is zero.
 
  • #37
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The spatial precision of a point can be infinitely augmented (Planck length be damned). In other words, no limits to how small space can be parsed. That's 'depth' in a way, but one need not restrict the understanding of 'depth' to conventional tridimensional space.

Never argue with a layman!
 
  • #38
Drakkith
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The spatial precision of a point can be infinitely augmented (Planck length be damned). In other words, no limits to how small space can be parsed. That's 'depth' in a way, but one need not restrict the understanding of 'depth' to conventional tridimensional space.

Never argue with a layman!
One needs to restrict the usage of terms here at PF to the standard convention used in science and engineering, otherwise you cannot have a meaningful discussion without pages and pages of back and forth arguing over what some term means. That's not helpful when people are trying to learn mainstream science.

In standard science and math a single point has no dimension and cannot have 'depth'. Furthermore, the division of space into smaller and smaller sections has absolutely nothing to do with depth unless you shoehorn some abstract meaning into it. Please don't do that.
 
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  • #39
Chronos
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There are good reasons to beleive there is a limit to how small something can be and stiill be something - e.g., HUP.
 
  • #40
Fervent Freyja
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Party poopers with no sense of humor.
Get to it, then! Send a camera into a black hole for me. I will throw a party in your honor and gift you with whatever you wish.
 
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  • #41
Khashishi
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A white hole is a time-reversed black hole. In classical kinematics and relativity, you can take any solution and time-reverse it and get another solution. But once you include thermodynamics, you see that most time-reversed solutions are not allowed. So, there's no reason to believe white holes exist.
 
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  • #42
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ok that makes a lot more sense to me once you explain how the math and the numbers for it worked I didn't start the thread but thank you :bugeye:
 

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