Black holes, White Holes and Baby Universes:

I do not accept that the "potential" for, or the "possibility" of, the "existence" of anything, would in any way "prove" or "mandate" or "manifest" that actual "existence" in any physical reality.

For example : - ALL human beings have the "potential" or "possibility" of being the next Newton or Einstein - but, even you Fork, must admit, that just by reading some of the Posts on this Forum, anyone can conclude that...well...need I say more?

 

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My doubt is with regards to the proper definition of an "Eternal BH"

The definition I ran into a decade ago, was the following.........
"A massless black hole which is a stable topological structure held together by the nonlinearity of its gravitational field."
at Eric Weisstein's
Science world Wolfram under Eternal Black Hole
http://scienceworld.wolfram.com/phys...BlackHole.html


The other definition I now see at various sites is simply a BH that does not evaporate due to Hawking Radiation.

The Eric Weisstein's definition was poo pooed and rubbished at another science forum by a couple of "self appraised" experts.
I take their rebuttal with a grain of salt.

I still see the Weisstein's definition as logically valid, if a BH mass does/can pass via an ERB and wormhole into another Universe and WH outpouring.
With all due respect for the answers and opinions given so far, I was wondering if we have an online cosmologist/Astro-physicist who can verify or invalidate the Eric Weisstein's definition.
Anyone else?

 

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It can't lose any mass through Hawking radiation because there is no mass. It's Eternal by definition. Because it's a theoretical possibility modeling it may aid in researching gravitational physics. Since the physics was done to show it's theoretically possible the spacetime that describes this model is eternal by definition.

 

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Theorists apply loop quantum gravity theory to black hole:

(Phys.org) —Physicists Rodolfo Gambini and Jorge Pullin of University of the Republic in Montevideo, Uruguay, and Louisiana State University respectively, have applied the theory of Loop Quantum Gravity (LQG) to a simplified black hole. In so doing, as they describe in their paper published in the journal Physical Review Letters, they suggest that instead of a singularity existing at its center, there is a portal to another universe.

In this new effort Gambini and Pullin applied LQG to a simplified model of a black hole. Their experiment showed that everything that was pulled into the black hole didn't compress to a singularity after all—instead it was compressed to a certain small size, then was spit out in another part of the universe or into another universe entirely.
Because their model worked so well, the two suggest that it would likely work with real black holes as well. If this new theory is correct, they note, it would do away with the information loss paradox and open the door to the possibility of black holes being portals to other universes.


Read more at: http://phys.org/news/2013-05-theorists-loop-quantum-gravity-theory.html#jCp

 

Thanks for your comments to me elsewhere, and I am going to venture a response here and hope you know that it is a layman level response for talking purposes, and not being presented as expert testimony

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ERB wormholes collapse almost instantly as I understand it. Other theories call for some way to keep the wormhole open, and one theorized solution is negative matter. Watch this: http://m.youtube.com/watch?v=HbwvTB...uri=%2Fwatch%3Fv%3DHbwvTBaLLqo%26autoplay%3D1

 

I see science and the scientific method as a body of knowledge gained by standing on the shoulders of giants, and adding to that knowledge by research, Innovation, Imagination and application.
But what personal hypothesis I have myself, are just ideas [great ones I might add

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] but short on mathematics, and as such, although what I understand of your suggestion seems interesting, my layman qualifications and the lack of mathematics, means my comments don't really count for much.

 

I think you misunderstand.
I speak of two distinct definitions of what an Eternal BH is........both appear as unlikely to exist in real life.....
The definitions are....
[1] A BH that does not experience Hawking Radiation, hence it never evaporates and would outlast the life of the Universe.
and
[2] A massless black hole which is a stable topological structure held together by the nonlinearity of its gravitational field.

 

A random question from a lay(woman)…does a black hole swallow anything and everything that comes near it, including light? If that is the case, how can they be detected with certainty? Thanks.

 

yes, but they aren't like a cosmic vacuum cleaner. stuff has to be on the correct trajectory just like any other cosmic object. they have stable orbits for photons. also stuff can get ejected by the polar jets formed from the rotating accretion disk.

 

I understand this explanation, thanks!


As an aside, I had always assumed that black holes would be hard to detect with certainty due to light not escaping.

 

if they have accretion disks then x-rays etc are emited by the infalling matter, we can detect this. polar jets also emit light. also if stars wre orbiting them, like the one at the centre of the Milky Way, then we can deduce that there is a BH there from their orbital periods.

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/990923a.html

http://www.nasa.gov/topics/universe/features/radio-particle-jets.html

 

Ok, got it. Thanks.

I thought this was helpful too...talks to your point about detection.

http://www.astro.umd.edu/~miller/poster1.html

 

BHs in the main are detected by their gravitational effects on matter/energy around them...accretion disks and the like....plus when scientists/Cosmologists see matter/energy virtually disappearing into nothing, and see X-rays being profusely emitted from around where it is disappearing, only one conclusion can be arrived at.
To put it another way, if Cosmologists do happen to be wrong about BHs, then there is something else out there far more mysterious and sinister....or we are waayyyy off with our model of gravity.

 

I'll try and answer this in more detail....Generally speaking matter falling into a BH doesn't just follow a radial path and get swallowed.
Matter actually spirals in towards the BH EH in ever decreasing circles, going faster and faster as it approaches the point of no return. In fact the speed can be very near "c" as it gets very near.
At this velocity, matter emits X-Rays and this is a telling tale.
Larger objects like another star/Pulsar etc that come within a certain distance of a BH will have matter sucked off the main body to form an accretion disk and then a gradual spiralling into the BH.

The polar jets of matter that we often see exiting the region of a BH, do not actually come from inside the BH.
It most probably is a charged rotating BH [we call them Kerr-Newman BHs] and what is theorised to happen is that matter as it is spiralling in, is twisted around by the space/time immediatley surrounding the EH, caused by the spinning BH [which we call frame dragging or the Lense-Thirring effect] and also the twisting of the magnetic field around the hole, is twisted away from the equatorial regions and ejected in the familiar polar jets at the poles.

And more attuned to your question, most BHs are observed because they do belong to a binary/trinary system and/or they are SMBHs at the center of galaxies, but if a BH was isolated and by itself in inter-galactic space with no matter/energy to feed off, there is really no way that we could detect it.
It would for all intents and purposes be undetectable.

 

Thanks for this paddoboy. I'm glad you expanded because it makes sense a bit more as to how they are detectable, but still...some disagree that black holes truly exist. Can stars become black holes?

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Stars certainly can and do become BHs.
Stars such as our Sun end up as White Dwarfs.....Stars around three times the mass of the Sun go supernova and leave a neutron/Pulsar behind...Stars larger then this become BHs after going supernova.
Betelgeuse and Eta Carinae are probably BH candidates.

Like I said, if BHs do not exist, then there is a far greater more mysterious unknown out there, to explain the observational evidence we do have.

 

Thanks for this!
So, I read that if a human "fell" into a black hole...he/she would be stretched out like spaghetti from the gravitational pull.

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If there is such a "place" called hell, that could be it.

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depends on their size. super massive ones, you wouldn't notice anything different crossing the event horizon. small ones, a few stellar masses, you would notice. it is the tidal effects, the difference in the gravity between your head and feet. the larger the hole the smaller the difference.

http://en.wikipedia.org/wiki/Spaghettification

 

As per Boris's answer....the smaller the BH, the more pronounced the tidal gravitational effects, and vice versa.


Professor Stephen Hawking said of BHs
"Äbandon all hope ye that enter here" quoting from Dante's "Inferno"

 

I hate when the second poster in a thread feels the need to quote the first, and I hate when people quote themselves.

You did both in one post.