Jump to content




Welcome to Unexplained Mysteries! Please sign in or create an account to start posting and to access a host of extra features.


- - - - -

Rethinking Black Holes


  • Please log in to reply
31 replies to this topic

#1    Startraveler

Startraveler

    Fleet Captain

  • Member
  • 4,539 posts
  • Joined:25 Jun 2006
  • Gender:Male
  • Location:New England

  • Knowledge Brings Fear.

Posted 03 July 2007 - 08:02 PM

This story is a few days old but very, very interesting.

Science

Quote

No More Black Holes?

By Phil Berardelli
ScienceNOW Daily News
21 June 2007
If new calculations are correct, the universe just got even stranger. Scientists at Case Western Reserve University in Cleveland, Ohio, have constructed mathematical formulas that conclude black holes cannot exist. The findings--if correct--could revolutionize astrophysics and resolve a paradox that has perplexed physicists for 4 decades.

On the surface, a black hole seems like a simple concept. It's a point in space where gravity grows infinitely strong. At a particular distance from the center of the hole--called the event horizon--gravity is already so strong not even light can escape. So material falls in never to be seen again. Calculations support this theory, but they also support something stranger. In 1974, theoretical physicist Stephen Hawking showed that thanks to quantum mechanics matter can escape black holes in a tricky way. By random chance, a particle-antiparticle pair can flit into existence straddling the event horizon. One partner falls into the hole, while the other just barely makes it free. Because of this effect, dubbed Hawking radiation, a black hole slowly evaporates, so that anything that enters is eventually released over billions or even trillions of years. But how can black holes be both airtight and leaky?

Physicist Lawrence Krauss and Case Western Reserve colleagues think they have found the answer to the paradox. In a paper accepted for publication in Physical Review D, they have constructed a lengthy mathematical formula that shows, in effect, black holes can't form at all. The key involves the relativistic effect of time, Krauss explains. As Einstein demonstrated in his Theory of General Relativity, a passenger inside a spaceship traveling toward a black hole would feel the ship accelerating, while an outside observer would see the ship slow down. When the ship reached the event horizon, it would appear to stop, staying there forever and never falling in toward oblivion. In effect, Krauss says, time effectively stops at that point, meaning time is infinite for black holes. If black holes radiate away their mass over time, as Hawking showed, then they should evaporate before they even form, Krauss says. It would be like pouring water into a glass that has no bottom. In essence, physicists have been arguing over a trick question for 40 years.

Asked why then the universe nevertheless seems to be full of black holes, Krauss replies, "How do you know they're black holes?" No one has actually seen a black hole, he says, and anything with a tremendous amount of gravity--such as the supermassive remnants of stars--could exert effects similar to those researchers have blamed on black holes. "All of our calculations suggest this is quite plausible," Krauss says.

Not so fast, says astronomer Kimberly Weaver of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Although she appreciates the physics the Case Western Reserve team is describing, the problem is "we have never observed any events that would back this up." At the site of the supermassive black hole at the center of the Milky Way, for example, she says astronomers routinely observe what looks like interstellar material disappearing without a trace. Also, no one has yet detected Hawking radiation, which would be prerequisite evidence for black hole evaporation, Weaver says.


Although it clearly presents the idea, I tend to think that article wasn't very well-written (in regard to some of the concepts). So I'll throw in an article from astronomy.com that adds a little more:

Quote

Rethinking black holes
A research team concludes it is impossible to lose something inside a black hole.

"Nothing there," Case Western Reserve University physicists concluded about black holes after spending a year working to calculate black hole formation. The research may solve the information-loss paradox that has perplexed physicists for the past 40 years.

"It's complicated and very complex," said Case physicists Tanmay Vachaspati, Dejan Stojkovic, and Lawrence Krauss, referring to the overall problem and their particular approach to solving it.

The physicists set out to discover just what happens once something enters and collapses into a black hole. In current thinking, once this happens, all information is lost. Yet, the researchers thought, if all information is lost, then laws of quantum physics are defied.

"If you define the black hole as some place where you can lose objects, then there is no such thing, because the black hole evaporates before anything is seen to fall in," Vachaspati said.

The team argues that information would remain forever on the event horizon the black hole's point of no return. The masses on the edge of the incipient black hole appear to be collapsing, but never actually fall inside the event horizon.

Researchers began by collapsing nonsingular matter to see if an event horizon formed, signaling the creation of a black hole.

They found while mass shrank in size, the matter never collapsed inside an event horizon. Evidence of pre-Hawking radiation a non-thermal radiation that allows information to be recovered from the collapsing mass may be the explanation for this.

"Non-thermal radiation can carry information in it unlike thermal radiation. This means that an outside observer watching some object collapse receives non-thermal radiation back and may be able to reconstruct all the information in the initial object, and so the information never gets lost," the team said.

According to the researchers, if new black holes form, information formed in the initial state would disappear in the black hole after a burst of thermal radiation.

Using Schrodinger formalism, the researchers suggest that information about energy emitted from radiation is long-evaporated before an event horizon forms.

"An outside observer will never lose an object down a black hole," Stojkovic said. "If you are sitting outside and throwing something into the black hole, it will never pass over, but will stay outside the event horizon, even if one considers the effects of quantum mechanics. In fact, since in quantum mechanics the observer plays an important role in measurement, the question of formation of an event horizon is much more subtle to consider."

The Case team's findings could be the beginning of a new era in black hole research. "From an external viewer's point it takes an infinite amount of time to form an event horizon, and the clock for the objects falling into the black hole appears to slow down to zero," said Krauss, director of Case's Center for Education and Research in Cosmology.

"This is one of the factors that led us to rethink this problem, and we hope our proposal at the very least will stimulate a broader reconsideration of these issues," Krauss added.

If black holes exist in the universe, the astrophysicists speculate, they were formed only at the beginning of time.



#2    Mr.United_Nations

Mr.United_Nations

    hi

  • Member
  • 9,304 posts
  • Joined:22 Apr 2006
  • Gender:Male
  • Location:Portsmouth

Posted 06 July 2007 - 07:04 PM

BLack holes are like giant tornados or shredders and they have been proven that they exist.


#3    Captain Kolak

Captain Kolak

    Alien Embryo

  • Member
  • Pip
  • 117 posts
  • Joined:02 Jun 2007
  • Location:This Universe

  • Do you really want to be decieved by your stupidity?

Posted 07 July 2007 - 08:10 PM

I find that very interesting. Need to do some research. But it does make sense though. But heres the problem I have. Time runs the same everywere through our perspectives. If you were anywere in the universe then time would feel "normal" for you. It is not until we look from a different referance point. So i don't think that time can "stop". Because then everything would have to "stop". Light, matter, energy etc. And maybe even gravity then? (Because if all matter stopped all charges would stop so then matter would basically fall apart and all and with no mass you can't have gravity. And if theres no gravity then it wouldn't be a singularity in which case there would be time. LOL. Now thats another paradox to add to the paradox book grin2.gif)


Any comments to my solution????



tongue.gif

Saying that gaps in the fossil record invalidate evolution is much like saying time doesn't exist between ticks of your digital watch

#4    Startraveler

Startraveler

    Fleet Captain

  • Member
  • 4,539 posts
  • Joined:25 Jun 2006
  • Gender:Male
  • Location:New England

  • Knowledge Brings Fear.

Posted 09 July 2007 - 09:53 PM

Quote

BLack holes are like giant tornados or shredders and they have been proven that they exist.


They're not really like shredders, they're just objects with very large gravitational pulls (close up). And we know that something with a large gravitational pull exists at the centers of galaxies and elsewhere, we just usually take it to be black holes. As one of the articles I quoted says:

Asked why then the universe nevertheless seems to be full of black holes, Krauss replies, "How do you know they're black holes?" No one has actually seen a black hole, he says, and anything with a tremendous amount of gravity--such as the supermassive remnants of stars--could exert effects similar to those researchers have blamed on black holes. "All of our calculations suggest this is quite plausible," Krauss says.


Quote

But heres the problem I have. Time runs the same everywere through our perspectives. If you were anywere in the universe then time would feel "normal" for you. It is not until we look from a different referance point. So i don't think that time can "stop". Because then everything would have to "stop". Light, matter, energy etc. And maybe even gravity then? (Because if all matter stopped all charges would stop so then matter would basically fall apart and all and with no mass you can't have gravity. And if theres no gravity then it wouldn't be a singularity in which case there would be time. LOL. Now thats another paradox to add to the paradox book grin2.gif)
Any comments to my solution????


Time doesn't quite stop, it just gets slower and slower, going asymptotically to zero (i.e. crawling closer and closer to 0 but never quite reaching it). And this isn't really new or revolutionary: it's been known for decades that clocks tick slower deeper in gravitational wells (i.e. a clock at the base of a tower ticks slightly more slowly than one at the top). The result is that somebody at the top of the tower sees time for somebody at the bottom ticking more slowly and somebody at the bottom correspondingly sees it going faster for somebody at the top (though, both, as you note experience it flowing "normally" for themselves). With a black hole the well is a lot deeper than the one in which the ends of a tower on earth reside so the effect gets quite a bit more pronounced. When  a star collapses, it faces the same problem as somebody falling toward a black hole: as it gets closer and closer to forming an event horizon time slows down more and more so that the time it takes to form tends toward infinity (i.e. the black hole is watching time speed up outside and pass through the universe's future history as it waits for the event horizon to form). But, apparently, the Hawking radiation that's predicted to evaporate a black hole over extremely long timescales is still going on and thus, in a sense, black holes evaporate before they actually form. So if you try to throw something into a black hole, it will take longer and longer to approach the event horizon the closer it gets--it would take an infinitely long time to cross, except the black hole itself wouldn't exist for an infinite time due to Hawking radiation, so it's effectively gone by the time the thing you threw makes it inside.


#5    Harte

Harte

    Supremely Educated Knower of Everything in Existence. He whose k

  • Member
  • 11,474 posts
  • Joined:06 Aug 2006
  • Gender:Male
  • Location:Memphis

  • Skeptic

Posted 11 July 2007 - 02:59 AM

This is only a very fine point.  I mean, if this is true, it's not in any way substantially different than the former theory, except it clears up a couple of things that some people might have thought were paradoxes, but never seemed so paradoxical to me.

Maybe the loss of information was a paradox, for quantum physics.  But the rest just seems weird, not paradoxical.

At any rate, it's not some great change, and the entities we refer to as "black holes" would still exist, just they are not precisely what we thought they were.

Harte

Posted Image
See the new Harte Mark III
And the Mayan panoramas on my pyramid pajamas haven't helped my little problem. - The Alan Parsons Project
Most people would die sooner than think; in fact, they do so. - Bertrand Russell
Anybody like Coleridge?

#6    Startraveler

Startraveler

    Fleet Captain

  • Member
  • 4,539 posts
  • Joined:25 Jun 2006
  • Gender:Male
  • Location:New England

  • Knowledge Brings Fear.

Posted 11 July 2007 - 07:07 AM

It isn't different from existing theory. That the event horizon takes an infinite time to form is a well-known result of the classical calculations. It was just thought by some that taking quantum mechanics into account would lead to a finite formation time, which, if Krauss and his coauthors are correct, is not the case. Gravitational collapse certainly still occurs but black holes would never actually be the end product of that collapse.


#7    SoldierOfPeace

SoldierOfPeace

    Alien Embryo

  • Member
  • Pip
  • 37 posts
  • Joined:10 Jul 2007

Posted 12 July 2007 - 07:29 PM

That's an absolutely fascinating article, but I'm not at all convinced. There is more than enough observable evidence that there are massive objects in the universe that swallow light and exert a very real gravitational force on other astral bodies. The stars at the center of the Milky Way have been shown to revolve around a common point. They move faster as they get closer, and slower as they move farther away, suggesting a very real attraction. The original article poses the question "how do we know those things are black holes?" Well----because those objects are what we've defined black holes to be. That's like asking how do we know that a couch is a couch. We've defined a certain object, with certain properties as a "couch" or as a "black hole." So the objects that we find matching that description are termed in the same way. We might very well be wrong about the physics involved or Hawking could have been wrong. Regardless---we know these objects exist, we've seen their effects. It's the same with Dark Energy and Dark Matter. The Universe should be slowing down given the amount of matter that exists. The fact that it's accelerating shows that there is obviously something else out there.

So in my mind, observations prove the existence of black holes.


#8    questionmark

questionmark

    Cinicus Magnus

  • Member
  • 39,647 posts
  • Joined:26 Jun 2007
  • Gender:Male
  • Location:Greece and Des Moines, IA

  • In a flat world there is an explanation to everything.

Posted 13 July 2007 - 01:39 PM

Everything can be "proven"or "disproven" by virtue of a formula.

The original observation of black holes was not mathematical but light anomalies that could only be explained if those things do exist.

The best example I have was the famous calculation of the maximum attainable speeds in the early 19th century, where a whole collegiate of physicist concluded that it would be impossible for a closed carriage to ever travel at a higher speed than 12 miles an hour because the passengers would suffocate.

Too bad Stevenson did not know that, he spoiled all those calculations with his train....

ED: Typo

Edited by questionmark, 13 July 2007 - 01:41 PM.

A skeptic is a well informed believer and a pessimist a well informed optimist
The most dangerous views of the world are from those who have never seen it. ~ Alexander v. Humboldt
If you want to bulls**t me please do it so that it takes me more than a minute to find out

about me

#9    Captain Kolak

Captain Kolak

    Alien Embryo

  • Member
  • Pip
  • 117 posts
  • Joined:02 Jun 2007
  • Location:This Universe

  • Do you really want to be decieved by your stupidity?

Posted 15 July 2007 - 11:47 AM

(To lasy to qoute so bare with me)

One of you said that time slows down so much that the things are barely moving. And by the time it reaches the black hole its gone. I think i have to disagree. Time appears to almost stop from our perspective. Which is not universal time (because suposingly there is no "universal time"). So the time for the matter getting sucked is the same as ours here. Its not until we cross the two referance points with each other that we notice a difference. But if there ws a sentient being, being sucked in, time would feel the same as it does for you or me. If somehow you could send a human into it without the humans gettin ripped apart somehowm time would feel normal. Now, I have no idea were im getting at so ill just stop here.

Saying that gaps in the fossil record invalidate evolution is much like saying time doesn't exist between ticks of your digital watch

#10    questionmark

questionmark

    Cinicus Magnus

  • Member
  • 39,647 posts
  • Joined:26 Jun 2007
  • Gender:Male
  • Location:Greece and Des Moines, IA

  • In a flat world there is an explanation to everything.

Posted 15 July 2007 - 12:55 PM

Quote

(To lasy to qoute so bare with me)

One of you said that time slows down so much that the things are barely moving. And by the time it reaches the black hole its gone. I think i have to disagree. Time appears to almost stop from our perspective. Which is not universal time (because suposingly there is no "universal time"). So the time for the matter getting sucked is the same as ours here. Its not until we cross the two referance points with each other that we notice a difference. But if there ws a sentient being, being sucked in, time would feel the same as it does for you or me. If somehow you could send a human into it without the humans gettin ripped apart somehowm time would feel normal. Now, I have no idea were im getting at so ill just stop here.


Is very useful anyway ... cause anybody can draw whatever conclusion they want to get at  devil.gif

A skeptic is a well informed believer and a pessimist a well informed optimist
The most dangerous views of the world are from those who have never seen it. ~ Alexander v. Humboldt
If you want to bulls**t me please do it so that it takes me more than a minute to find out

about me

#11    Harte

Harte

    Supremely Educated Knower of Everything in Existence. He whose k

  • Member
  • 11,474 posts
  • Joined:06 Aug 2006
  • Gender:Male
  • Location:Memphis

  • Skeptic

Posted 15 July 2007 - 06:51 PM

Quote

(To lasy to qoute so bare with me)

One of you said that time slows down so much that the things are barely moving. And by the time it reaches the black hole its gone. I think i have to disagree. Time appears to almost stop from our perspective. Which is not universal time (because suposingly there is no "universal time"). So the time for the matter getting sucked is the same as ours here. Its not until we cross the two referance points with each other that we notice a difference. But if there ws a sentient being, being sucked in, time would feel the same as it does for you or me. If somehow you could send a human into it without the humans gettin ripped apart somehowm time would feel normal.


This is probably true.  What it means is that the individual falling into the hole would, had he a window, be able to watch the evolution of the universe occuring outside in extreme, extreme "fast forward" mode.  If the black hole was massive enough, the Hawking radiation would evaporate it over a longer time period, meaning that the eyewitness might even be able to witness the end of the universe before he ever hit that event horizon.

The theory clearly states that he would at the very least witness the complete evaporation of the black hole before he ever reached the even horizon, which would itself never actually form anyway.

Harte

Posted Image
See the new Harte Mark III
And the Mayan panoramas on my pyramid pajamas haven't helped my little problem. - The Alan Parsons Project
Most people would die sooner than think; in fact, they do so. - Bertrand Russell
Anybody like Coleridge?

#12    questionmark

questionmark

    Cinicus Magnus

  • Member
  • 39,647 posts
  • Joined:26 Jun 2007
  • Gender:Male
  • Location:Greece and Des Moines, IA

  • In a flat world there is an explanation to everything.

Posted 15 July 2007 - 07:17 PM

Quote

The theory clearly states that he would at the very least witness the complete evaporation of the black hole before he ever reached the even horizon, which would itself never actually form anyway.


Making this the nearest thing to eternal physical life that we can imagine... what were those alchemists (of the first variety)  looking for again?


A skeptic is a well informed believer and a pessimist a well informed optimist
The most dangerous views of the world are from those who have never seen it. ~ Alexander v. Humboldt
If you want to bulls**t me please do it so that it takes me more than a minute to find out

about me

#13    Startraveler

Startraveler

    Fleet Captain

  • Member
  • 4,539 posts
  • Joined:25 Jun 2006
  • Gender:Male
  • Location:New England

  • Knowledge Brings Fear.

Posted 15 July 2007 - 07:21 PM

Quote

There is more than enough observable evidence that there are massive objects in the universe that swallow light and exert a very real gravitational force on other astral bodies. The stars at the center of the Milky Way have been shown to revolve around a common point. They move faster as they get closer, and slower as they move farther away, suggesting a very real attraction. The original article poses the question "how do we know those things are black holes?" Well----because those objects are what we've defined black holes to be. That's like asking how do we know that a couch is a couch. We've defined a certain object, with certain properties as a "couch" or as a "black hole."


Well, words are important because they're carrying concepts along with them. "Black hole" suggests a certain body with a certain structure that's understood in a very particular way. If Krauss et al. are right then it might be more accurate to go back to the old name for black holes: frozen stars. Sure, changing the name doesn't change what's at the center of galaxies but this isn't just quibbling over words, this is attempting to determine the very nature of just what those things are. For example, you mentioned dark matter and dark energy. Suppose dark matter turns out not to be an exotic new form of nonbaryonic matter but instead the effects are actually due to modifications of the physics governing gravitation. Certainly we'd have to think about altering the name. As for dark energy, at least one prominent cosmologist has suggested its not a particularly good or descriptive name for the stuff and something like "smooth tension" would be much more insightful. So the words are important for illuminating the concepts.

Edited by Startraveler, 15 July 2007 - 07:22 PM.


#14    Captain Kolak

Captain Kolak

    Alien Embryo

  • Member
  • Pip
  • 117 posts
  • Joined:02 Jun 2007
  • Location:This Universe

  • Do you really want to be decieved by your stupidity?

Posted 16 July 2007 - 01:21 AM

Quote

This is probably true.  What it means is that the individual falling into the hole would, had he a window, be able to watch the evolution of the universe occuring outside in extreme, extreme "fast forward" mode.  If the black hole was massive enough, the Hawking radiation would evaporate it over a longer time period, meaning that the eyewitness might even be able to witness the end of the universe before he ever hit that event horizon.

The theory clearly states that he would at the very least witness the complete evaporation of the black hole before he ever reached the even horizon, which would itself never actually form anyway.

Harte




Thanks for that comment. That got my brain straightened up. That would be awsome, watching a black hole evaporate so quickly. But the question i have is this. Is there any observations that tell us how fact the matter is falling into the black hole? Because it hink i have a dilemna. If the matter falling into the black hole falls in quickyl from our perspective, it means that by the time the object in question gets into the black hole BEFORE it evaporates. So then the question of how time runs in the and around the black hole must be questioned.

Saying that gaps in the fossil record invalidate evolution is much like saying time doesn't exist between ticks of your digital watch

#15    questionmark

questionmark

    Cinicus Magnus

  • Member
  • 39,647 posts
  • Joined:26 Jun 2007
  • Gender:Male
  • Location:Greece and Des Moines, IA

  • In a flat world there is an explanation to everything.

Posted 16 July 2007 - 01:23 PM

Quote

Thanks for that comment. That got my brain straightened up. That would be awsome, watching a black hole evaporate so quickly. But the question i have is this. Is there any observations that tell us how fact the matter is falling into the black hole? Because it hink i have a dilemna. If the matter falling into the black hole falls in quickyl from our perspective, it means that by the time the object in question gets into the black hole BEFORE it evaporates. So then the question of how time runs in the and around the black hole must be questioned.


The problem is that we have not observed a black hole long enough to give us a real idea of the time sequences. We can, more or less explain what is happening there. Maybe even why it is happening but we could not say much more at this time.
Besides, we would have to know what type of black hole we are talking about. The physics of a rotating, charged, black hole is a little different from the uncharged (static or non-rotating) one.

If you really want to get int this all I can really do is give you a list of books to find in your library:

Popular books:

Melia, Fulvio (2003). The Edge of Infinity. Supermassive Black Holes in the Universe. Cambridge U Press. ISBN 978-0-521-81405-8.
Pickover, Clifford (1998). Black Holes: A Traveler's Guide. Wiley, John & Sons, Inc. ISBN 0-471-19704-1.
Thorne, Kip S. (1994). Black Holes and Time Warps. Norton, W. W. & Company, Inc. ISBN 0-393-31276-3.
Hawking, Stephen (1998). A Brief History of Time. Bantam Books, Inc. ISBN 0-553-38016-8.
Melia, Fulvio (2003). The Black Hole at the Center of Our Galaxy. Princeton U Press. ISBN 978-0-691-09505-9.

If you want to get deeper in I can also get you a list of university level books.




A skeptic is a well informed believer and a pessimist a well informed optimist
The most dangerous views of the world are from those who have never seen it. ~ Alexander v. Humboldt
If you want to bulls**t me please do it so that it takes me more than a minute to find out

about me




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users