Discussion in 'Science and Technology' started by W.G.Ewald, Jan 25, 2014.
[1401.5761] Information Preservation and Weather Forecasting for Black Holes
Incredible picture of a massive black hole that is so powerful it has prevented TRILLIONS of stars from forming | Mail Online
NASA has released a stunning image of a black hole that is so massive and so powerful that it has prevented trillions of stars from forming around it.
The black hole is surrounded by super-heated gases - shown in purple. At the very center of the gas is a very galaxy cluster - that is home to the black hole.
Galaxies can be seen swirling around - and bending into the black hole, pictured in yellow.
The entire spectacular occurrence is located 3.9 billion light years from Earth in a galaxy cluster called RX J1532.
Extreme power: The black hole can be seen in center of the galaxy cluster in the middle of the purple gaseous mass. Galaxy clusters can be seen in yellow
The phenomenon was captured by a compilation of images taken by two of NASA most powerful space telescopes - the Chandra X-ray Observatory and the Hubble Space Telescope.
The galaxy at the center of the gaseous cloud is massive, about a quadrillion - a thousand trillion - times the size of our sun.
The black hole is one of the most powerful ever recorded.
Black holes are rips in space time that prevent anything, including light, from escaping. They are formed when a massive star collapses in on itself after its life cycle ends.
NASA astronomers have deduced, with the help of the Karl G. Jansky Very Large Array in New Mexico, that the black hole is beginning to drill massive holes in the gaseous mass.
The black hole is creating 'cavities' in the gas - show by gaps in the purple hue - that is keeping the gas super-heated and preventing stars from forming
The holes, which can be seen on either size of the black hole, are each the size of our own Milky Way - about 100,000 light years across.
Astronomers believe that the 'cavities' in the gas are releasing shock fronts into the gas that keep it super-heated - and prevent stars from forming.
The energy is the result of the cavities expanding rapidly.
That, scientists believe, is how the powerful black hole is able to create a massive - dead space in the galaxy cluster.
Whom do we need to believe ? NASA or Stephen Hawking ?
Stephen Hawking admits 'there are no black holes - but there are GREY holes | Mail Online
Stephen Hawking has shocked physicists by admitting 'there are no black holes'.
In a paper published online, Professor Hawking instead argues there are 'grey holes'
'The absence of event horizons means that there are no black holes - in the sense of regimes from which light can't escape to infinity,' he says in the paper, called Information Preservation and Weather Forecasting For Black Holes.
He says that the idea of an event horizon, from which light cannot escape, is flawed.
He suggests that instead light rays attempting to rush away from the black holeâ€™s core will be held as though stuck on a treadmill and that they can slowly shrink by spewing out radiation.
Hawking told the journal Nature: 'There is no escape from a black hole in classical theory. [But quantum theory] enables energy and information to escape from a black hole'.
A full explanation of the process, Hawking admits, would require a theory that successfully merges gravity with the other fundamental forces of nature.
However, that is a goal that has eluded physicists for nearly a century.
'The correct treatment,' Hawking told Nature, 'remains a mystery.'
The professorâ€™s grey hole theory would allow matter and energy to be held for a period of time before being released back into space.
Hawkingâ€™s latest work was prompted by a talk he gave via Skype to a meeting at the Kavli Institute for Theoretical Physics in Santa Barbara, California, in August 2013.
The professorÂ¿s grey hole theory would allow matter and energy to be held for a period of time before being released back into space.
It tries to address what is known as the black-hole firewall paradox, which has puzzled scientists for almost two years.
It stems from a theory where scientists tried to imagine what would happen to an astronaut unlucky enough to fall into a black hole.
Black hole expert Don Page, of the University of Alberta in Edmonton, Canada, admits: 'The picture Hawking gives sounds reasonable.'
But theoretical physicist Joseph Polchinski of the Kavli Institute is sceptical and insists: 'In Einsteinâ€™s gravity, the black-hole horizon is not so different from any other part of space.
'We never see space-time fluctuate in our own neighbourhood: it is just too rare on large scales.'
Raphael Bousso, a theoretical physicist at the University of California, Berkeley, and former student of Hawking's, admits many physicists will find Hawkingâ€™s work â€œabhorrentâ€.
He says: â€œThe idea that there are no points from which you cannot escape a black hole is in some ways an even more radical and problematic suggestion than the existence of firewalls.
'But the fact that weâ€™re still discussing such questions 40 years after Hawkingâ€™s first papers on black holes and information is testament to their enormous significance.'
A BRIEF HISTORY OF PROFESSOR HAWKING'S WORK
In a paper published online, Professor Hawking instead argues there are 'grey holes' and not black holes, as he first thought.
In the 1970s, already confined to a wheelchair, he produced a stream of first class research, including probably his most important contribution to cosmology.
This was the discovery of Hawking radiation, which allows a black hole to leak energy and gradually fade away to nothing.
By applying quantum mechanics to black holes, he had taken the first steps to combining quantum theory and general relativity.
One describes the universe at the sub-atomic level, and the other at very large scales.
Bringing the two theories together is one of the great unfulfilled goals of modern physics.
In the 1980s, Prof Hawking and Professor Jim Hartle, from the University of California at Santa Barbara, proposed a model of the universe which had no boundaries in space or time.
The concept was described in A Brief History Of Time, which sold 25 million copies worldwide.
Hawking was proved wrong in his black hole theories by a Physicist.
I don't remember his name but saw a program on Discovery/NGC.
Leonard Susskind - Wikipedia, the free encyclopedia ?
Sensational headlines apart, both have not denied that something like a black hole exists. Hawkins has questioned on the properties of a black hole. The widely accepted theory being that a black hole sucks matter and energy with no loss. Hawkins has proposed that these are released into space after some time.
The reason behind Hawkins going for such a headline could be because he likes to have a laugh on all those creationist nuts out there!
Or perhaps to make other scientists start doing some work proving him wrong instead of sitting idle.
What's your take on 2-D holographic theory of Black Holes ?
Indian physicist resolved Black Hole paradox much before Stephen Hawking | NDTV.com
Holes in what ? Dark matter ? I also am skeptic on black holes' existence.
He didn't say that black holes don't exist, but that black holes don't have a definite event horizon as was previously thought.
I don't understand Hawking's clarification. Could somebody explain? Of course both light and matter can and does escape black holes. Isn't that where the relativistic jets (the long columns of light shooting out of the bright elliptical in @kseeker's post above) originate from? And come to think of it, why is the black hole so bright in that picture? It's supposed to be "black".
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