Do black holes really exist?

dafloppyone

dafloppyone

dafloppyone

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The conventional view of a black hole includes an "event horizon" beyond which nothing can escape. But a new calculation suggests collapsing matter may never get dense enough to form an event horizon, and "black stars" would form instead (Illustration: XMM-Newton/ESA/NASA)




Black holes might not exist – or at least not as scientists have imagined, cloaked by an impenetrable "event horizon". A controversial new calculation could abolish the horizon, and so solve a troubling paradox in physics.

The event horizon is supposed to mark a boundary beyond which nothing can escape a black hole's mavity. According to the general theory of relativity, even light is trapped inside the horizon, and no information about what fell into the hole can ever escape. Information seems to have fallen out of the universe.

That contradicts the equations of quantum mechanics, which always preserve information. How to resolve this conflict?

One possibility researchers have proposed in the past is that the information does leak back out again slowly. It may be encoded in a hypothetical flow of particles called Hawking radiation, which is thought to result from the black holes' event horizons messing with the quantum froth that is ever-present in space.

But other researchers argue the information may never have been cut off in the first place. Tanmay Vachaspati and his colleagues at Case Western Reserve University in Cleveland, Ohio, US, have tried to calculate what happens as a black hole is forming. Using an unusual mathematical approach called the functional Schrodinger equation, they follow a sphere of stuff as it collapses inwards, and predict what a distant observer would see.

They find that the mavity of the collapsing mass starts to disrupt the quantum vacuum, generating what they call "pre-Hawking" radiation. Losing that radiation reduces the total mass-energy of the object – so that it never gets dense enough to form an event horizon and a true black hole. "There are no such things", Vachaspati told New Scientist. "There are only stars going toward being a black hole but not getting there."

Dark and dense

These so-called "black stars" would look very much like black holes, says Vachaswati. From the point of view of a distant observer, mavity distorts the apparent flow of time so that matter falling inwards slows down. As it gets close to where the horizon would be, the matter fades, its light stretched to such long wavelengths by the dark object's mavity that it would be nearly impossible to detect.

But because the pre-Hawking radiation prevents the formation of a black hole with a true event horizon, the matter never quite fades entirely. As nothing is cut off from the rest of the universe, there is no information paradox.

The idea faces firm opposition from other theoretical physicists, however. "I strongly disagree," says Nobel laureate Gerard 't Hooft of Utrecht University in the Netherlands. "The process he describes can in no way produce enough radiation to make a black hole disappear as quickly as he is suggesting." The horizon forms long before the hole can evaporate, 't Hooft told New Scientist.

Lab test

Steve Giddings of the University of California in Santa Barbara, US, is also sceptical. "Well-understood findings apparently conflict with their picture," he told New Scientist. "To my knowledge, there hasn't been an attempt to understand how they are getting results that differ from these calculations, which would be an important step to understanding if this is a solid result."

There could be a way to test the new theory. The Large Hadron Collider being constructed at CERN in Geneva might just be capable of making microscopic black holes – or, if Vachaspati is right, black stars. Unlike the large, long-lived black holes in space, these microscopic objects would evaporate fast. The spread of energies in their radiation might reveal whether or not an event horizon forms.

Alternatively, colliding black stars in space might reveal themselves, as Vachaspati says they would churn out not only gravitational waves (like colliding black holes) but also gamma rays. He suggests that they could be responsible for some of the gamma-ray bursts seen by astronomers.

Journal reference: Physical Review D (In press)

http://space.newscientist.com/article.ns?id=dn12089&feedId=online-news_rss20
 
Since we are on the scientific stuff, when the space shuttle lands, how heavier does it and the astronauts return? I know it's a small number but I am just wondering :D
 
Theres also the wormhole theory (ie the black hole is simply part of an hourglass-like structure that connects to another part of space\time). But less plausible than what is being described above.
 
There is the theory of the mobius. A twist in the fabric of space where time becomes a loop, from which there is no escape. When we reach that point, whatever happened will happen again, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop, where time becomes a loop,
 
The conventional view of a black hole includes an "event horizon" beyond which nothing can escape. But a new calculation suggests collapsing matter may never get dense enough to form an event horizon, and "black stars" would form instead (Illustration: XMM-Newton/ESA/NASA)

I got confused after that line :/
 
It's an interesting debate, given that black holes are inherently unobservable anyway! We can see and measure their effects, but actually seeing a black hole is something that we cannot do.

It's certainly an interesting idea, but since it's clearly just a mathematical argument (like so much theoretical physics these days :() it's hard to put any weight behind it.
 
Well i do see how they know just by looking at something, they are too far away and just by looking at something through a telescope, how do you know that it sucks in and crushes everything around it? Its weird though, if it is true where the hell does everything inside it go?
 
tomanders91 said:
Well i do see how they know just by looking at something, they are too far away and just by looking at something through a telescope, how do you know that it sucks in and crushes everything around it?
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You look at the momentum distribution of the matter around your prospective black hole; then you do some calculations and work out what the mass and size of the stuff at the center must be. You feed that data into your models, and they make a prediction over whether it's a black hole or not.

Its weird though, if it is true where the hell does everything inside it go?
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It's compacted down to an 'infinitesimally small' region at the center of the black hole: what we call a singularity. According to our models, at least: you always have to be careful when talking about the region inside the event horizon of a black hole. By definition it's out of causal contact, so it's impossible for us to look inside. It could be the secret playground of the Easter bunny for all we know.
 
tomanders91 said:
Well i do see how they know just by looking at something, they are too far away and just by looking at something through a telescope, how do you know that it sucks in and crushes everything around it? Its weird though, if it is true where the hell does everything inside it go?
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Its not a case of looking at it through a telescope as that would be pretty impossible to do.

Imagine having a massive box sucking everything in around it. The box is really strong and wont allow anything out of it. It will never burst or anything like that. Never change shape. The box will just get heavier and heavier and heavier but it the space it takes will remain the same. As the ammount of matter in the box increases then so does the mavity. Then as it sucks more stuff in the mavity is that strong it wont allow any light out of it.

So its not a case of what you can see, its a case of what you cant see is the give away
 
Arcade Fire said:
We won't. Really.
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The above comes from Arcade Fire. Head of PR - Large Hadron Collider dept. CERN.

*Arcade Fire finishes typing his/her post (no offence intended ;) ). Then nervously looks over their shoulder at the large scary machine.* "Silly people, nothing like that's gonna happen. It can't..."

Sadly while I'm a big astronomy buff I won't be able to add any relevant additions to this debate. Except that Black Holes are inherently more cool. :D
 
Quite an interesting attempt to explain things but I don't think I'm convinced.

It would have to radiate A LOT of energy, going by what they are saying and from what I gather no one has measured any spikes that could really be big enough
 
helmet said:
Yes, my entire wage falls into one each month.
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dn120891600py3.jpg

:p
 
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