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[Phoenix]

Black holes are staples of science fiction and many think astronomers have observed them indirectly. But according to a physicist at the Lawrence Livermore National Laboratory in California, these awesome breaches in space-time do not and indeed cannot exist.

Over the past few years, observations of the motions of galaxies have shown that some 70% the Universe seems to be composed of a strange 'dark energy' that is driving the Universe's accelerating expansion.

George Chapline thinks that the collapse of the massive stars, which was long believed to generate black holes, actually leads to the formation of stars that contain dark energy. "It's a near certainty that black holes don't exist," he claims.

Black holes are one of the most celebrated predictions of Einstein's general theory of relativity, which explains gravity as the warping of space-time caused by massive objects. The theory suggests that a sufficiently massive star, when it dies, will collapse under its own gravity to a single point.

But Einstein didn't believe in black holes, Chapline argues. "Unfortunately", he adds, "he couldn't articulate why." At the root of the problem is the other revolutionary theory of twentieth-century physics, which Einstein also helped to formulate: quantum mechanics.

In general relativity, there is no such thing as a 'universal time' that makes clocks tick at the same rate everywhere. Instead, gravity makes clocks run at different rates in different places. But quantum mechanics, which describes physical phenomena at infinitesimally small scales, is meaningful only if time is universal; if not, its equations make no sense.

This problem is particularly pressing at the boundary, or event horizon, of a black hole. To a far-off observer, time seems to stand still here. A spacecraft falling into a black hole would seem, to someone watching it from afar, to be stuck forever at the event horizon, although the astronauts in the spacecraft would feel as if they were continuing to fall. "General relativity predicts that nothing happens at the event horizon," says Chapline.

Quantum transitions

However, as long ago as 1975 quantum physicists argued that strange things do happen at an event horizon: matter governed by quantum laws becomes hypersensitive to slight disturbances. "The result was quickly forgotten," says Chapline, "because it didn't agree with the prediction of general relativity. But actually, it was absolutely correct."

This strange behaviour, he says, is the signature of a 'quantum phase transition' of space-time. Chapline argues that a star doesn't simply collapse to form a black hole; instead, the space-time inside it becomes filled with dark energy and this has some intriguing gravitational effects.

Outside the 'surface' of a dark-energy star, it behaves much like a black hole, producing a strong gravitational tug. But inside, the 'negative' gravity of dark energy may cause matter to bounce back out again.

If the dark-energy star is big enough, Chapline predicts, any electrons bounced out will have been converted to positrons, which then annihilate other electrons in a burst of high-energy radiation. Chapline says that this could explain the radiation observed from the centre of our galaxy, previously interpreted as the signature of a huge black hole.

He also thinks that the Universe could be filled with 'primordial' dark-energy stars. These are formed not by stellar collapse but by fluctuations of space-time itself, like blobs of liquid condensing spontaneously out of a cooling gas. These, he suggests, could be stuff that has the same gravitational effect as normal matter, but cannot be seen: the elusive substance known as dark matter.

Nature Article from Lawrence Livermore Scientist

 

[Blackcherry]

Yes they do exists

 

[Cooper]

I didn't really read the article, just wanted to say welcome back. How are you feeling?

 

[Phoenix]

I didn't really read the article, just wanted to say welcome back. How are you feeling?

I added a post to Kayla's thread. Should pretty much sum up everything.

Link

 

[way more]

Its not terribly crazy, he just says it ass backwards. He thinks instead of collapsed stars black holes are dark-energy stars. Maybe in 100 years he'll be proved right.

 

[AntoneM]

so, what he's saying is that when a very large star goes supernova something happens during the colapse that causes the remaining matter to become dark energy? Why the phase change? and what the fuck is dark energy wanyway? is it simply anti-particles?

 

[Nerevar]

I saw this earlier on slashdot.

He makes some good points, and I think he might be on to something. It does create some interesting questions as to how we are searching for a "grand unified theory" about how to correlate Einstein's two great developments (quantum mechanics and relativity), and we might be looking in the wrong places. I am curious as to how something develops "negative gravity." Is that a consequence of dark matter (being the opposite of "normal" matter)?

 

[LakeEarth]

I won't pretend I know the principles of quantum mechanics and relativity, but as long as this guy isn't a crackpot I say it's a possibility. You never "know" anything in this once flat, once centre of the universe world.

 

[Escape Goat]

Isnt' dark matter a blanket term for the 90% of the galaxy we cant see?

 

[Hitokage]

In general relativity, there is no such thing as a 'universal time' that makes clocks tick at the same rate everywhere. Instead, gravity makes clocks run at different rates in different places. But quantum mechanics, which describes physical phenomena at infinitesimally small scales, is meaningful only if time is universal; if not, its equations make no sense.

The problem is that relativistic effects on time have been directly observed and tested, and put into practical use. The clocks on the GPS sattelites are set to run at a different rate to compensate for the slight change in time in orbit from the surface of the earth.

Isnt' dark matter a blanket term for the 90% of the galaxy we cant see?

Yes, hence the name. It's matter that should be there but we can't see. BTW, I saw another article on somebody arguing that inflation might explain the observed expansion that prompted the need to invoke "dark energy". It'll be interesting to see how things turn out.

 

[COCKLES]

Maximillian disproves of this thread.

 

[Raistlin]

Hitokage,

Ah ... beat me to it.

'universal time' my ass.

 

[The Shadow]

He's not a crackpot. The guy is a physicist at Lawrence Livermore and I'm sure earned his position.

But just because you're incredibly smart doesn't mean you can't be wrong. He's completely ignoring the fact that the time distortions relativity predicts have been observed. They don't go away just because it's convenient to ignore them, particularly at the large scale that he's talking about. Sure in the QM world but not with black holes. Moreover, AFAIK quantum mechanics doesn't require "universal" time, it's just that gravity at such small scales is so infinitesimally small that it's simply not calculated. Why search for a graviton if time can't distort anyway?

Relativity and QM are both right and have been proved time and time again. However, I don't think either is adequate enough to properly explain what exactly a black hole is. Relativity predicts their occurrence and they've been observed. Relativity can't explain what happens inside and I doubt QM can either.

Only a universal theory can IMO.

Isnt' dark matter a blanket term for the 90% of the galaxy we cant see?

Dark matter, yes. Dark energy, no. They're two different ideas really. The former probably regular matter we just can't see. The later, a repulsion effect that we see the Universe going though. The Universe is expanding at an increasing rate and no one can explain exactly why. It's contrary to what you'd expect so the effect is called "Dark Energy".

Yes, hence the name. It's matter that should be there but we can't see. BTW, I saw another article on somebody arguing that inflation might explain the observed expansion that prompted the need to invoke "dark energy". It'll be interesting to see how things turn out.

You're thinking of Alan Guth I believe. He came up with the inflation theory and the "false vacuum" which created the universe. It also explains quite neatly why the universe is flat.

 

[WordAssassin]

But, but, haven't scientists created teeny tiny black holes in labs? I thought I read something abut that in Discovery a while ago, in an article about alternate dimensions. How they've been doing tests with lab-generated black holes to see if it'd be possible to rip through the fabric of our dimension into a sister dimension. (Of course, they'd also have to locate a sister dimension before they could rip it open, but now I'm getting off topic.)

 

[Tekky]

Depends upon what your definition of "exists" is.

 

[Hitokage]

I meant an adjustment to inflation theory, not the kind that's commonly presented... or something, I really don't remember the specifics all that well.