Black Holes

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
ruffready said:
I remember from astronomy any star greater than 8 solar masses when collapsing into itself, will turn into a black hole. Anything under 8 solar masses will become a "white drawf"-I guess they might have to re-write all that in 5 years or so.
Yep, we might have to re-name this thread -

"The Phenomena formerly known as Black Holes"! :D
 

Rubyait

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Sep 10, 2004
Messages
1,186
Reaction score
6
Points
54
Black holes: The ultimate quantum computers?

Nearly all of the information that falls into a black hole escapes back out, a controversial new study argues. The work suggests that black holes could one day be used as incredibly accurate quantum computers – if enormous theoretical and practical hurdles can first be overcome.

Black holes are thought to destroy anything that crosses a point of no return around them called an "event horizon". But in the 1970s, Stephen Hawking used quantum mechanics to show black holes do emit radiation, which eventually evaporates them away completely.

Originally, he argued that this "Hawking radiation" is so random that it could carry no information out about what had fallen into the black hole. But this conflicted with quantum mechanics, which states that quantum information can never be lost. Eventually, Hawking changed his mind and in 2004 famously conceded a bet, admitting that black holes do not destroy information.

But the issue is far from settled, says Daniel Gottesman of the Perimeter Institute in Waterloo, Canada. "Hawking has changed his mind, but a lot of other people haven't," he told New Scientist. "There are still a lot of questions about what's really going on."

Quantum entanglement
Now, Seth Lloyd of the Massachusetts Institute of Technology in the US, has used a controversial quantum model called final-state projection to try to solve the paradox. The model holds that under certain extreme circumstances – such as the intense gravitational field of a black hole, objects that would ordinarily have several options for their behaviour have only one. For example, a black hole could cause a coin thrown into it to always come up "heads".

This allows information to escape from a black hole without any ambiguity about how to interpret it. The information escapes through a quantum process called entanglement, in which objects are not independent if they have interacted with each other or come into being through the same process. They become linked, or entangled, such that changing one invariably affects the other, no matter how far apart they are.

In black holes, Hawking radiation arises just inside the event horizon and has two components – one that leaves the black hole and another that falls towards the point-like singularity that is the black hole itself.

These components are entangled, so when matter that has been sucked into the black hole interacts with the infalling Hawking radiation at the singularity, the interaction instantaneously produces a change in the Hawking radiation that has escaped the black hole. Because the final-state projection model forces this interaction to behave in only one way, this radiation therefore carries information about material inside the black hole.

Smooshed up
Gottesman and colleague John Preskill of the California Institute of Technology in Pasadena, US, found that previous calculations by other researchers using this model allowed information to escape for only certain interactions between the infalling matter and the infalling Hawking radiation. Now, Lloyd has calculated that the process is quite robust – the random nature of these interactions means the system is almost perfectly entangled.

That suggests the outgoing Hawking radiation carries away nearly all of the information of the matter – such as a spaceship – that falls into the black hole. According to Lloyd, the most that could be lost is half a quantum unit of information, or 0.5 qubit.

"Passengers on a spaceship would like some guarantee that when they fall into this black hole and get smooshed into the singularity, they can be recreated as it evaporates," Lloyd told New Scientist. "With a few simple precautions, the travellers would be almost exactly the same, with less than an atom of difference."

Lloyd also says the work suggests black holes could be used as quantum computers. "We might be able to figure out a way to essentially program the black hole by putting in the right collection of matter," he says.

Mission implausible
But both applications would require an understanding of the properties of specific black holes, says Gottesman. "And you'd have to collect every little piece of Hawking radiation because the spaceship would get spread out with everything that fell into the black hole – ever," Gottesman says. "So you'd have to sort out which bits were the spaceship and which bits were other things. It's implausible."

Lloyd agrees. Understanding how to decode the outgoing Hawking radiation will require researchers to weave together quantum physics and general relativity into a seamless theory of quantum gravity – a goal that has so far proved elusive. "Until we understand quantum gravity, we're not going to be running Linux on a black hole," he jokes.

But beyond the practical difficulties, Gottesman says the work has a more serious theoretical flaw. Despite the fact that just half a qubit of information is lost, "from a fundamental point of view, there is no real difference between a little bit of information being lost and a lot being lost," he says.

"In standard quantum mechanics, no information is ever lost, so if he is right, quantum mechanics would have to be revised to allow information loss. We have no real idea of what theory could take its place."

http://www.newscientistspace.com/article/dn8836.html
 
A

Anonymous

Guest
What happens if you chuck an elephant into a black hole?

Found this in Newscientist.com

The elephant and the event horizon
26 October 2006
Exclusive from New Scientist Print Edition.


What happens when you throw an elephant into a black hole? It sounds like a bad joke, but it's a question that has been weighing heavily on Leonard Susskind's mind. Susskind, a physicist at Stanford University in California, has been trying to save that elephant for decades. He has finally found a way to do it, but the consequences shake the foundations of what we thought we knew about space and time. If his calculations are correct, the elephant must be in more than one place at the same time.

In everyday life, of course, locality is a given. You're over there, I'm over here; neither of us is anywhere else. Even in Einstein's theory of relativity, where distances and timescales can change depending on an observer's reference frame, an object's location in space-time is precisely defined. What Susskind is saying, however, is that locality in this classical sense is a myth. Nothing is what, or rather, where it seems.

...As researchers forge ahead in their quest to unify quantum mechanics and gravity, non-locality may help point the way. For instance, quantum gravity should obey the holographic principle. That means there might be redundant information and fewer important dimensions of space-time in the theory. "This has to be part of the understanding of quantum gravity," Giddings says. "It's likely that this black hole information paradox will lead to a revolution at least as profound as the advent of quantum mechanics."

That's not all. The fact that space-time itself is accelerating - that is, the expansion of the universe is speeding up - also creates a horizon. Just as we could learn that an elephant lurked inside a black hole by decoding the Hawking radiation, perhaps we might learn what's beyond our cosmic horizon by decoding its emissions. How? According to Susskind, the cosmic microwave background that surrounds us might be even more important than we think. Cosmologists study this radiation because its variations tell us about the infant moments of time, but Susskind speculates that it could be a kind of Hawking radiation coming from our universe's edge. If that's the case, it might tell us something about the elephants on the other side of the universe.

New Scientist article


So what does it all mean really?
 

eburacum

Papo-furado
Joined
Aug 26, 2005
Messages
3,528
Reaction score
1,594
Points
169
Okay, I can see whwere this is coming from. In relativity, every observer has something called a frame of reference, which is unique to that observer. You really can't compare results from one frame of reference to another, especially where an event horizon gets in the way.

For an observer watching an elephant fall into a black hole, the elephant just seems to get slower and slower, always approaching but never reaching the event horizon. That is the situation as seen from the observer's 'frame of reference'.

But for the elephant, he or she just falls straight in, in a matter of seconds. That is the situation as seen from the elephant's 'frame of reference'.

In relativity, it doesn't matter that the two perceptions of events are so different; the observer can never talk to the elephant again, because of the event horizon, so they can't compare notes.

Except; recent ideas suggest that information might be transferred via the Hawking Radiation that pours (or trickles) out of black holes. So perhaps the elephant can talk to the observer.

Myself, I doubt it. The information content of Hawking radiation is probably quite low; so you will probably only just have time to say 'hello' before the universe ends.
The Universe is funny like that; it always covers its back.
 
A

Anonymous

Guest
What if we sent in a probe made of benzium into the hole, and it was transmitting quantum signals by laser or something?

What about that?

Can it be done?
 

eburacum

Papo-furado
Joined
Aug 26, 2005
Messages
3,528
Reaction score
1,594
Points
169
Perhaps; but it would be very, very, difficult to decode the message transitted via the hawking radiation.

I would like to point interested parties in the direction of one of my favourite short sci-fi stories; this involves a trip into a black hole, and out again. Nothing in this story conflicts with current understanding, although it is very far-fetched.

'Approaching Perimelasma' by Geoffrey Landis
http://www.infinityplus.co.uk/stories/perimelasma.htm
 

OneWingedBird

Beloved of Ra
Joined
Aug 3, 2003
Messages
15,658
Reaction score
6,915
Points
284
wouldn't the elephant be ripped apart by tidal forces before it got anywhere near the event horizon?
 

Spookdaddy

Cuckoo
Joined
May 24, 2006
Messages
6,321
Reaction score
6,309
Points
294
Location
Midwich
Re: What happens if you chuck an elephant into a black hole?

If his calculations are correct, the elephant must be in more than one place at the same time.
If, as a toddler, I'd only known that every time my mum said she couldn't be in two places at once all I had to do was find an elephant...
 

Xanatico

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Nov 11, 2005
Messages
1,101
Reaction score
9
Points
54
Actually an elephant would be a bad idea. A smaller, lighter creature would be more spread out, according to the Heidelberg uncertainty principle. So a hamster would be better for helping you out.

Darkriver: I think that is why it is just a thought experiment.
 

Spookdaddy

Cuckoo
Joined
May 24, 2006
Messages
6,321
Reaction score
6,309
Points
294
Location
Midwich
Xanatico said:
Actually an elephant would be a bad idea. A smaller, lighter creature would be more spread out, according to the Heidelberg uncertainty principle. So a hamster would be better for helping you out.
No - wouldn't work. There's no way my mum will fit on the back of a hamster.
 

eburacum

Papo-furado
Joined
Aug 26, 2005
Messages
3,528
Reaction score
1,594
Points
169
Actually, if the black hole was large enough (for instance the supermassive balck hole supposed to be at the centre of our galaxy) even an elephant wouldn't experience enough tidal force to be ripped apart. In theory the elephant wouldn't even notice the point when it crossed the event horizon.

But I think Susskind is wrong; the Cosmic Microwave background is far too powerful to be considered a kind of Hawking radiation, and besides, it has a perfectly good explanation as the relic radiation from the decoupling era.
 

Xanatico

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Nov 11, 2005
Messages
1,101
Reaction score
9
Points
54
I was under the impression Hawking radiation is actually created outside the black hole. That it consists of virtual particles that live on gravitational energy stolen from the black hole. So I´m not sure how much it would be affected by anything inside the black hole, other than an increase or decrease in mass.
 

eburacum

Papo-furado
Joined
Aug 26, 2005
Messages
3,528
Reaction score
1,594
Points
169
I was under the impression Hawking radiation is actually created outside the black hole. That it consists of virtual particles that live on gravitational energy stolen from the black hole.
I believe the actual explanation is more complex than that; Hawking now seems to believe that some information can be extracted from it, but it is very difficult to make any sense of that information.
 
A

Anonymous

Guest
Timble2 said:
I don't think the Worldwide Fund for Nature, the RSPCA, etc would be very happy....
We'll chuck them in as well, to see if we're right about quantum entanglement and gravity and relitivity and the whole general sort of mish mash.
 

OldTimeRadio

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 15, 2005
Messages
5,525
Reaction score
141
Points
114
My Mom never let me do the elephant trick in the living room, especially when the curtains and the upholstery were new.
 

OldTimeRadio

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 15, 2005
Messages
5,525
Reaction score
141
Points
114
Little Willie built a Stargate and shoved an elephant through,

But when he brought it back again it was naught but noxious goo.

That was just the first experiment - so then for another

Will put through his baby sister and his little brother.
 
A

Anonymous

Guest
Are we already inside a 5D Black Hole?

Take a look at this and tell me what you think;

Life inside a black hole

10 February 2006
NewScientist.com news service
Paul Wesson

WE ALL know what happens if you fall into a black hole. It's not pretty - you get ripped limb from limb before vanishing down the plughole.

However, there is a way for you to live inside a black hole: find one that has five dimensions. Life inside a 5D black hole is known to be rather more sustainable than it is in the 4D version. In the 4D case, you would experience "tidal" forces that vary so vastly over short distances that your body would be pulled apart. But in the 5D case, there is no physical plughole, and the tidal forces are negligible, so you could happily explore without fear of dismemberment. And, according to the results of my research, you may be doing that right now. A mathematical analysis says that our universe may well be a 5D black hole (General Relativity and Gravitation), vol 37, p 1339).
http://www.newscientist.com/channel/fun ... -hole.html
 

Timble2

Imaginary Person
Joined
Feb 9, 2003
Messages
5,847
Reaction score
1,635
Points
234
Location
In a Liminal Zone
OldTimeRadio said:
Little Willie built a Stargate and shoved an elephant through,

But when he brought it back again it was naught but noxious goo.

That was just the first experiment - so then for another

Will put through his baby sister and his little brother.
:D :yeay:

The little Willie, is a much neglected poetic form.
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
coldelephant said:
Are we already inside a 5D Black Hole?

Take a look at this and tell me what you think
I like it! 8)
 

OldTimeRadio

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 15, 2005
Messages
5,525
Reaction score
141
Points
114
Timble2 said:
:D :yeay:
The little Willie, is a much neglected poetic form.
Here are two more originals:

Little Willie fired a rocket into space -
At the porthole you could see his sister's face.
Will promised the girl she would reach the stars
But instead she got eaten by a thing on Mars.


And:

Little Willie, according to the Trib,
Axed the baby to pieces in its crib.
Now this wasn't one of Willie's usual sins -
He was merely trying to create....twins.


I've composed DOZENS of these things, but don't know where to publish them here, since the FTMB doesn't seem to have a humor topic, as such.

And I DO try to keep postings on-topic. Mea culpa for this one.
 

ramonmercado

CyberPunk
Joined
Aug 19, 2003
Messages
50,340
Reaction score
23,909
Points
284
Location
Eblana
Published online: 18 May 2007; | doi:10.1038/news070514-21
How to survive in a black hole
There's no escape, but how can you maximize your remaining time?
Philip Ball







Aaaaaaaaaaargh: how to draw out your torturous fall into a black hole.

NASA

So there you are: you discover that your spaceship has inadvertently slipped across the event horizon of a black hole — the boundary beyond which nothing, not even light, can escape the hole's fearsome gravity. The only question is how you can maximize the time you have left. What do you do?

A common idea in physics is that you shouldn't try to blast your way out of there. Black holes, it's said, are like the popular view of quicksand: the harder you struggle, the worse things become.

But Geraint Lewis and Juliana Kwan of the University of Sydney in Australia say this is a myth. Their analysis of the problem, soon to be published in the Proceedings of the Astronomical Society of Australia1, shows that in general your best bet is indeed to turn on the rocket's engine. You'll never escape, but you'll live a little longer.

Falling into a black hole is a strange affair. Because the hole's gravity distorts space-time, a far-off observer watching an object crossing the event horizon sees time for that object appear to slow down — a clock falling into a black hole would appear, from the outside, to tick ever slower. At the horizon itself, time stops, and the object stays frozen there for the remaining lifetime of the Universe.

But this isn't how things seem to the in-falling object itself. Indeed, if the black hole is big enough, nothing noticeable happens when a spaceship crosses its event horizon — you could stray inside without realizing. Yet once inside, nothing can save you from being crushed by the hole's gravity sooner or later.

Live long and prosper

Clearly, an astronaut in that situation might prefer it to be later. For a supermassive black hole such as that thought to exist at the Galactic Centre, the survival time could be hours. To stretch it out for as long as possible, the astronaut might be tempted to turn on rocket thrusters and try to head outwards, away from the hole's fatal 'singularity' at the centre.

But best not to, according to some sources. An article on black holes on the cosmology website of the University of California, Berkeley, for example, says "the harder you fire your rockets, the sooner you hit the singularity. It's best just to sit back and enjoy the ride."

Lewis and Kwan say this is mistaken. They point out that the analysis is usually done by thinking about a person who falls into the black hole starting from a state of rest at the event horizon. In that case, it's true that accelerating away from the singularity by using the rocket thrusters will only speed your demise. The longest survival time possible in that instance is free fall. Because all paths lead inevitably to the singularity, trying to travel faster - in any direction - only takes you there quicker.

Long and winding road

But in general a person falling past the horizon won't have zero velocity to begin with. Then the situation is different — in fact it's worse. So firing the rocket for a short time can push the astronaut back on to the best-case scenario: the trajectory followed by free fall from rest.

"There is one longest road - the freefall road starting from rest - as well as many shorter roads," Lewis explains. "If you cross the event horizon on one of the shorter roads, you can fire your rocket to move you on to the longest road."

But this has to be done judiciously. "If you overdo it, you will overshoot the longest road and end up on a shorter road on the other side," says Lewis. So you only want to burn your rocket for a certain amount of time, and then turn it off. "Once you know how fast you have passed through the event horizon, it is reasonably straightforward to calculate how long you need to burn your rocket to get on to the best path," he says. "The more powerful the rocket, the quicker you get on to this path." Starship captains, take note.

There's nothing particularly surprising in this analysis, but black-hole experts say that debunking this common misconception could have an educational value. "It's a misconception I had when I first did relativity many years ago, and one which I have heard in discussions with others," says Lewis. "It has generated a substantial discussion on the Wikipedia entry about black holes."

He adds that "even Einstein had a very hard time attempting to fathom just what is going on as things fall into a black hole."

Visit our newsblog to read and post comments about this story.



Top



References
Lewis G. F. & Kwan J.et al. Publ. Astr. Soc. Australia, in press (2007).



Story from [email protected]:
http://news.nature.com//news/2007/070514/070514-21.html
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
Biggest black hole in the cosmos discovered
11:50 10 January 2008
NewScientist.com news service
David Shiga, Austin

The most massive known black hole in the universe has been discovered, weighing in with the mass of 18 billion Suns. Observing the orbit of a smaller black hole around this monster has allowed astronomers to test Einstein's theory of general relativity with stronger gravitational fields than ever before.

The black hole is about six times as massive as the previous record holder and in fact weighs as much as a small galaxy. It lurks 3.5 billion light years away, and forms the heart of a quasar called OJ287. A quasar is an extremely bright object in which matter spiralling into a giant black hole emits copious amounts of radiation.

But rather than hosting just a single colossal black hole, the quasar appears to harbour two – a setup that has allowed astronomers to accurately 'weigh' the larger one.

The smaller black hole, which weighs about 100 million Suns, orbits the larger one on an oval-shaped path every 12 years. It comes close enough to punch through the disc of matter surrounding the larger black hole twice each orbit, causing a pair of outbursts that make OJ287 suddenly brighten.
General relativity predicts that the smaller hole's orbit itself should rotate, or precess, over time, so that the point at which it comes nearest its neighbour moves around in space – an effect seen in Mercury's orbit around the Sun, albeit on a smaller scale.

Bright outburstsIn the case of OJ287, the tremendous gravitational field of the larger black hole causes the smaller black hole's orbit to precess at an incredible 39° each orbit. The precession changes where and when the smaller hole crashes through the disc surrounding its larger sibling.
About a dozen of the resulting bright outbursts have been observed to date, and astronomers led by Mauri Valtonen of Tuorla Observatory in Finland have analysed them to measure the precession rate of the smaller hole's orbit. That, along with the period of the orbit, suggests the larger black hole weighs a record 18 billion Suns.

A couple of other black holes have been estimated to be as massive, but their masses are less certain, says Valtonen. That's because the estimates were based on the speed of gas clouds around the black holes, and it is not clear whether the clouds are simply passing by the black holes or actually orbiting them.

But Tod Strohmayer of NASA's Goddard Space Flight Center in Maryland, US, says he is not convinced that Valtonen's team has really measured the mass of the large black hole in OJ287 accurately.
That's because only a handful of the outbursts have been measured with high precision, making it difficult to determine if the precession scenario is responsible for the outbursts. "Obviously, if subsequent timings continue to agree with the model, then that would provide further support," he told New Scientist.

Just how big can black holes get? Craig Wheeler of the University of Texas in Austin, US, says it depends only on how long a black hole has been around and how fast it has swallowed matter in order to grow. "There is no theoretical upper limit," he says.

The new research also tested another prediction of general relativity – that the black holes should spiral towards each other as they radiate energy away in the form of gravitational waves, or ripples in space. This radiation affects the timing of the disc crossings and their accompanying outbursts.
The most recent outburst occurred on 13 September 2007, as predicted by general relativity. "If there was no orbital decay, the outburst would have been 20 days later than when it actually happened," Valtonen told New Scientist, adding that the black holes are on track to merge within 10,000 years.

Wheeler says the observations of the outbursts fit closely with the expectations from general relativity. "The fact that you can fit Einstein's theory [so well] ... is telling you that that's working," he says.
The research was presented on Wednesday at a meeting of the American Astronomical Society in Austin, Texas, US.

http://space.newscientist.com/article/d ... ef=dn13166
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
Device mimics black hole event horizon
By Roger Highfield, Science Editor
Last Updated: 6:01pm GMT 13/02/2008

A team of researchers in Scotland has been able to boldly go where science fiction writers have only dreamt of visiting - inside the maw of a black hole, to crack some of the deepest mysteries of the cosmos.

Black holes, the remains of collapsed stars, are the most extraordinary objects in the universe, where the pull of gravity is so intense that light is sucked in if it strays beyond a boundary called the event horizon.

Now it seems these horizons can be mimicked using a table-top device that harnesses lasers to create an artificial black hole, according to a study by Prof Ulf Leonhardt of the University of St Andrews that could help win a Nobel prize for the world's best known physicist, Prof Stephen Hawking.

At St Andrews, Prof Leonhardt works on what are called quantum catastrophes, where so-called "singularities" can be created where the laws of wave physics are in danger of breaking down. Black holes are also singularities, where the pull of gravity is so intense that even light is sucked in.

The professor told the recent the Cosmology Meets Condensed Matter meeting in London that his team accomplished the feat of simulating key features of a black hole by firing lasers down an optical fibre, exploiting how different wavelengths of light move at different speeds within the fibre.

His team first shot a relatively slow moving laser pulse through the fibre, and then sent a faster "probe wave" chasing after it.

The slower light pulse distorts the optical properties of the fibre, forcing the speedy probe wave to slow down dramatically when it catches up so it becomes trapped and can never overtake the pulse's leading edge, so that it acts in just the same way as a black hole event horizon, beyond which light cannot escape.

And the measurements by Prof Leonhardt, Dr Chris Kuklewicz and Dr Friedrich Koenig at St Andrews, with Dr Thomas Philbin of the University of Erlangen, agree with the predictions of cosmologists, who have already worked out exactly how light should change frequency as it approaches an event horizon - from both the outside or the inside of a black hole.

Prof Hawking's chance of winning the Nobel prize has improved markedly because this device makes it possible to test his theories, which make specific predictions about the event horizon - the rim of a black hole.

"We show by theoretical calculations that such a system is capable of probing the quantum effects of horizons, in particular Hawking radiation," say the St Andrews team in a preprint of their paper.

Prof Hawking predicts that radiation would be given off at the horizon of black holes so that they would evaporate. In his book, The Universe in a Nutshell, the Cambridge University physicist said that only smaller black holes give off enough "Hawking radiation" to be detectable and there do not seem to be many of them around. "That is a pity. If one were discovered, I would get a Nobel prize."

Prof Ray Rivers at Imperial College London tells New Scientist: "They've done some clever stuff to give us a chance of seeing Hawking radiation for the first time."

http://www.telegraph.co.uk/earth/main.j ... ace113.xml
 

bazizmaduno

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Feb 12, 2003
Messages
280
Reaction score
4
Points
49
What...?

His team first shot a relatively slow moving laser pulse through the fibre, and then sent a faster "probe wave" chasing after it.

The slower light pulse distorts the optical properties of the fibre, forcing the speedy probe wave to slow down dramatically when it catches up so it becomes trapped and can never overtake the pulse's leading edge, so that it acts in just the same way as a black hole event horizon, beyond which light cannot escape.
Surely, it's not the optical properties of the mediun the pulse travel through that cause this effect - sure, I can imagine that a pulse would change the properties of the medium to such an extent that it would melt - that would certainly affect the following pulse...?

Is this to do with the permittivity (sp) of the medium? or as the faster pulse gets near to the slower pulse some sort of entanlement takes place? But, I thought entanglement needed a pair of pulse/photons to be entangled from their 'creation'

Can't get me head round this one... :?

STEPHEN!!!
 

IvanVolle

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Mar 11, 2008
Messages
275
Reaction score
14
Points
34
Zombie Stars
It’s a Star-Eat-Star Universe
A new study offers a possible solution to the riddle of the antimatter cloud in the galaxy’s core.
By Adam T. Hadhazy, posted April 11th, 2008.

"Zombie-like behavior in certain star systems may generate the mysterious antimatter cloud at the center of our Milky Way galaxy, according to a new study. This phenomenon of “dead” stars devouring their stellar neighbors shows how significant quantities of antimatter could be produced in the cosmos.

Recent satellite measurements amazed scientists by revealing that the antimatter cloud is irregular in shape. As it turns out, the cloud’s lopsidedness closely corresponds to the distribution of a particular kind of binary star system. These matching patterns imply a strong link between the two, though other theories remain for the cloud’s origins.

“We have seen something that has given us a clue in explaining a long-term mystery,” says Gerry Skinner, a senior research scientist at the University of Maryland and an author of the study published in the journal Nature in January.

Astronomers cumbersomely classify the suspected antimatter-source stars as “hard” low-mass X-ray binary systems (LMXBs). In these double-star arrangements, one of the stars is either a neutron star or a black hole, which are the diminutive remnants of an immense sun. This dense, revenant star wields powerful gravitational forces that leech gases from a normal, lower-mass companion star.

This feasting spews out gobs of energy as the super-heated gas, or plasma, from the unfortunate donor star is accelerated in a whirlpool around the ghoulish mini-star. The reactions discharge substantial amounts of antimatter, as well as the X-rays that help give these star systems their name."

http://scienceline.org/2008/04/11/physi ... ntimatter/
 

ramonmercado

CyberPunk
Joined
Aug 19, 2003
Messages
50,340
Reaction score
23,909
Points
284
Location
Eblana
Soon they'll be so cheap everyone will have one!

Artificial Black Hole Created in Chinese Lab
http://www.popsci.com/technology/articl ... our-pocket
By Stuart Fox Posted 10.15.2009 at 3:56 pm 14 Comments


Pocket Black Hole The icons depict the shape of the energy-trapping ridges on the disc at the center and the edges via arXiv.org
Just because most black holes are solar-system-sized maelstroms with reality-warping gravitational pulls doesn't mean you can't have one in your pocket! That's right, just in time for the holidays comes the pocket black hole. Designed by scientists at the Southeast University in Nanjing, China, this eight-and-a-half-inch-wide disk absorbs all the electromagnetic radiation you throw at it, with none of the pesky time dilation and Hawking radiation associated with the larger, interstellar versions.

Unlike a regular black hole, which traps light using the gravitational pull of the dead star at its core, this simple metal disc uses the geometry of 60 concentric rings of metamaterials to lock up light for good. The metamaterial "resonators" that make up the rings affect the magnetic properties of passing light, bending the beams into the center of the disc, and trapping them in the etched maze-like grooves.

But wait, there's more! These discs don't destroy the energy of the trapped light, and emit heat when trapping ambient radiation. That means these metamaterial black holes could serve as the basis for solar panels that capture every wavelength of the electromagnetic spectrum. And do so near-perfectly, to boot.

Call now! Operators are standing by.*

*NOTE: No operators are actually standing by.

[via Nature News]
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
Horizon - 2009-2010

4. Who's Afraid of a Big Black Hole?


Black holes are one of the most destructive forces in the universe, capable of tearing a planet apart and swallowing an entire star. Yet scientists now believe they could hold the key to answering the ultimate question - what was there before the Big Bang?

The trouble is that researching them is next to impossible. Black holes are by definition invisible and there's no scientific theory able to explain them. Despite these obvious obstacles, Horizon meets the astronomers attempting to image a black hole for the very first time and the theoretical physicists getting ever closer to unlocking their mysteries. It's a story that takes us into the heart of a black hole and to the very edge of what we think we know about the universe

http://www.bbc.co.uk/iplayer/episode/b0 ... lack_Hole/
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
A universe could exist 'inside every black hole,' claims scientist
A hidden universe could exist inside every black hole, a Polish cosmologist has claimed.
By Amy Willis
Published: 4:25PM BST 02 Aug 2010

Using an adaptation of Einstein's general theory of relativity, Nikodem Poplawski, of Indiana University, Bloomington, analysed the theoretical motion of particles entering a black hole.

He concluded that it was possible for a whole new universe to exist inside every black hole, which could mean that our own universe could be inside a black hole as well.

"Maybe the huge black holes at the centre of the Milky Way and other galaxies are bridges to different universes," he told New Scientist.

Explaining his theory in the journal Physics Letters B, he said he used the Einstein-Cartan-Kibble-Sciama (ECKS) theory of gravity, in his analysis to account for the angular momentum of particles in a black hole. Doing this it made it possible to calculate a quality of space-time called torsion, a property believed to repel gravity.

He says instead of matter reaching infinite density in a black hole called "singularities" in Einstein's theory of relativity - the behaviour of the space-time acts more like a spring being compressed with matter rebounding and expanding continuously.

Dr Poplawski explains that this "bounce-back" effect is caused by the torsion of space-time having a repulsive force against the gargantuan strength of gravity in a black hole.

Dr Poplawski also claims that this recoiling effect could be what has led to our expanding universe that we observe today and could explain why our universe is flat, homogeneous and isotropic without needing cosmic inflation.

It is hard to see how we could test whether or not Dr Poplawski's theory is correct; the force of gravity in black holes is such that nothing can escape, so no information about what is going on inside one can ever reach us.

However, according to Dr Poplawski, if we were living in a spinning black hole then the spin would transfer to the space-time inside, meaning the universe would have a preferred direction - something we would be able to measure. Such a preferred direction could be related to the observed imbalance of matter and anti-matter in the universe and could explain the oscillation of neutrinos.

http://www.telegraph.co.uk/science/spac ... ntist.html

More here:
http://en.wikipedia.org/wiki/Nikodem_Poplawski

and far more than you really want to know here:
http://en.wikipedia.org/wiki/Alternativ ... relativity
 

rynner2

Gone But Not Forgotten
(ACCOUNT RETIRED)
Joined
Aug 7, 2001
Messages
55,242
Reaction score
9,039
Points
284
Supercomputer clue to black holes

The colossal black holes at the centres of galaxies probably formed shortly after the Big Bang, a study suggests.

Some of these behemoths are billions of times more massive than our Sun.

Supercomputer simulations indicate the conditions for the birth and growth of these giants could have been set in play by the merger of galaxies when the cosmos was just a few hundred million years old.

The research, by Lucio Mayer and colleagues, is published in Nature.

The team's modelling found that the collision and union of two young galaxies could produce an enormous disc of rotating gas, and that this disc could become unstable and fall in on itself in rapid time.

The simulation showed gas with a mass equivalent to hundreds of millions of Suns accumulating in a small region of space in just a few thousand years after the merger.

And the properties of this cloud meant it could gravitationally collapse at high speed directly into a black hole.

Even a "seed" hole of a few hundred million solar masses could then go on to become a billion-solar-mass hole in very short order by continuing to accumulate gas, the modelling found.

Today, enormous black holes are observed to lie at the centres of most large galaxies. Understanding how they came into being and how they evolved is a major question in astrophysics.

"There is an amazing correlation between black holes and their galaxies," observed Professor Marta Volonteri from the University of Michigan.

"Every time you look in a galaxy for a [supermassive] black hole, you find it; and the mass of the black hole is typically a 1,000 times less than the mass of the galaxy.


"How has such a great correlation been established? How is it possible they knew so well about each other throughout these past 13 billion years? So we really want to know how the black holes started and how they grew with time," she told BBC News.

Professor Volonteri was not part of the team which did the modelling but the originator of the theory tested by Professor Mayer at the University of Zurich.

Mayer's group said the new research challenged the idea that galaxies grew in a hierarchical fashion - in incremental steps that see gravity pull small masses together to form progressively larger structures.

"Our result shows that big structures - both galaxies and massive black holes - build up quickly in the history of the Universe," said co-worker Dr Stelios Kazantzidis from Ohio State University.

If that is the case, it has important consequences.

"For example, the standard idea, that a galaxy's properties and the mass of its central black hole grow in parallel, will have to be revised," Dr Kazantzidis said.

"In our model, the black hole grows much faster than the galaxy. So it could be that the black hole is not regulated at all by the growth of the galaxy. It could be that the galaxy is regulated by the growth of the black hole."

http://www.bbc.co.uk/news/science-environment-11087715
 
Top