I was hoping it was an announcement by Stephen Hawking that it was just a massive hoax he made up during a boring party and everyone believed him.JamesBr said:
Stephen Hawking Claims "There Are No Black Holes"
- Thread starter Cognimancer
- Start date
I am totally going to perform under that name when I get into the music industry. Watch this space!JamesBr said:
He hasn't claimed that black holes don't exist, or even claimed that black holes 'as we understand them' don't exist. All he's done is proposed an alternate model that might turn out to be better than the one we had previously.
I laughed really hard at this. Its a perfect summation of my thoughts on the matter (Or lack of matter as the case may be! - huehueheuheuhue).Roofstone said:
My initial reaction to reading this was. "My cat's breath smells like cat food."
Hey, I'm a guy in a wheel chair who can't really move my body. What can I do?
Answer: Turn science on its head over and over again. Once you've convinced people that it's right side up, turn it over again.
Answer: Turn science on its head over and over again. Once you've convinced people that it's right side up, turn it over again.
My reaction exactly. I especially like how they've put quotation marks around something he clearly didn't say.Vegosiux said:
Perhaps we need to make it so you need some kind of licence to cover science news? To get one you'd need to pass a test where you tell apart actual scientific theories, and the plots of Star Trek episodes.
Kinda sorta.NeutralDrow said:
Light, as in photons, always moves at ~300,000,000 meters per second. It's a fact of the universe, to our current understanding of physics. Things can happen that can make us perceive the light as moving slower (the most obvious example is how there are some galaxies/stars/etc in the universe that the Earth will never be able to see), but those are generally tricks instead of actually slowing light. In the example I gave, the reason for that is that the space between those stars and Earth is expanding at FTL speeds. It's kinda like doing a race in a go cart while the finish line is being driven around by a formula-1 car.
I was all set to type out a long post on how you're effectively just making fallacious conclusions, but DracoSuave already typed out a mostly apropos response. So I'm just going to quote him.wulfy42 said:
DracoSuave said:
If you'd like to know what's actually going on here, I recommend the book "The Black Hole War" by Leonard Susskind. I'll summarize as best I can - I'm a layman but I have a pretty keen interest in the subject.
What's at stake here is the physicists' concept of "information". Information, in physics, has several important attributes - for example, it cannot be transmitted faster than the speed of light, or c (quantum entanglement/teleportation does not violate this rule because it does not transmit information. In case you were wondering). The term c is probably a better choice than "speed of light" as c is the speed limit of ANYTHING in the universe, and this is of course the significance of a black hole - when you compress enough mass into a small enough space, you create a region where escape velocity exceeds c, and the boundary of that region is what we call the event horizon. A more important attribute of information, for this discussion anyway, is that it is indestructible, and it is conserved in all reactions - even if it would be impossible to do in any practical sense, for example, it is theoretically possible to take the ashes of a burned book (together, I suppose, with the smoke and heat released from the combustion), and "rewind" the burning process to get the original book back. Everything that happens in the universe is thought to be rewindable in this way, and if an exception were to be found, some major parts of quantum physics would fall completely apart.
Black holes are that exception.
Or at least, they were once thought to be. Stephen Hawking was the first one to point this fact out, and it's the source of his famous quote "not only does God play dice, sometimes he throws them where they cannot be seen".
The problem is entropy - you can think of every event in the universe (like our burning book) as following this equation:
Original State + Entropy -> Final State
And just like simple addition, physics expects the equation to work in the other direction, too.
Final State - Entropy -> Original State
But black holes don't seem to have any entropy! They were thought to be smooth, featureless, almost perfectly mathematical entities, possessing only mass, charge, and spin. (Another memorable quote from this period was "a black hole has no hair"). A book that falls into a black hole isn't even recoverable in theory, it is permanently lost, indistinguishable from every other piece of matter that's passed through the event horizon.
OK, so maybe the information isn't available to us anymore but it's still somewhere, you might think. Just trapped behind the event horizon, lost to us, maybe, but not destroyed. Turns out, no - Hawking made matters worse when he observed that black holes ought to emit radiation, and to decay as they do so - this is a weird one, but the explanation isn't too tough to understand... In quantum mechanics, even perfectly empty space is constantly bubbling with activity, as matched pairs of particles and anti-particles pop into existence for a brief period of time, then reconnect and annihilate each other. This is happening all the time, everywhere. But at the event horizon of a black hole, there's a possibility that the particle with the opposite charge of the black hole will be pulled in, and the other will be simultaneously repelled. Since opposites not only attract, they annihilate, that means the black hole is constantly losing some of its mass to these reactions, and releasing it in the form of particles with no connection, information-wise, to the matter that made up the hole itself (save charge and mass). It was bad enough when information was falling into the black hole and being trapped there, but to find out that it was also being permanently destroyed was a major crisis for quantum physics. The theory not only couldn't explain it, but major parts of it would have to be thrown out if it were true. And since we have, in fact, found evidence of Hawking radiation, quantum physics has a serious problem.
Has, or maybe had. "The Black Hole War" describes how at least part of the conundrum was resolved. A number of physicists (none with Hawking's PR department, sadly) developed a theory in which the event horizon was, itself, the black hole's entropy. If you've read something recently about the universe being a hologram, this is exactly the line of reasoning that's under discussion... The surprising result that all of the information that had fallen into the black hole might be preserved right at its perimeter lead to the even more surprising result that all information in the universe can be thought of as residing at *its* perimeter. (If you know what a nonogram, or Japanese Crossword is, it's an extremely helpful metaphor here). Hawking himself seems to have signed off on this theory, having paid off a $1 bet he made that the problem of black hole entropy would never be solved.
Which makes me wonder where this new theory of his is coming from... I'm not sure if he's just restating the work other people have done (wouldn't be the first time), or if there's some further difficulty he's trying to resolve that I'm not aware of. In any case, this doesn't mean anything like "there are no black holes" - there are, and there's likely one at the heart of every single galaxy, including our own. It just means they don't behave like the perfect geometrical fields of force predicted by relativity, but are rather stormy, complex, and, well, hairy things after all.
What's at stake here is the physicists' concept of "information". Information, in physics, has several important attributes - for example, it cannot be transmitted faster than the speed of light, or c (quantum entanglement/teleportation does not violate this rule because it does not transmit information. In case you were wondering). The term c is probably a better choice than "speed of light" as c is the speed limit of ANYTHING in the universe, and this is of course the significance of a black hole - when you compress enough mass into a small enough space, you create a region where escape velocity exceeds c, and the boundary of that region is what we call the event horizon. A more important attribute of information, for this discussion anyway, is that it is indestructible, and it is conserved in all reactions - even if it would be impossible to do in any practical sense, for example, it is theoretically possible to take the ashes of a burned book (together, I suppose, with the smoke and heat released from the combustion), and "rewind" the burning process to get the original book back. Everything that happens in the universe is thought to be rewindable in this way, and if an exception were to be found, some major parts of quantum physics would fall completely apart.
Black holes are that exception.
Or at least, they were once thought to be. Stephen Hawking was the first one to point this fact out, and it's the source of his famous quote "not only does God play dice, sometimes he throws them where they cannot be seen".
The problem is entropy - you can think of every event in the universe (like our burning book) as following this equation:
Original State + Entropy -> Final State
And just like simple addition, physics expects the equation to work in the other direction, too.
Final State - Entropy -> Original State
But black holes don't seem to have any entropy! They were thought to be smooth, featureless, almost perfectly mathematical entities, possessing only mass, charge, and spin. (Another memorable quote from this period was "a black hole has no hair"). A book that falls into a black hole isn't even recoverable in theory, it is permanently lost, indistinguishable from every other piece of matter that's passed through the event horizon.
OK, so maybe the information isn't available to us anymore but it's still somewhere, you might think. Just trapped behind the event horizon, lost to us, maybe, but not destroyed. Turns out, no - Hawking made matters worse when he observed that black holes ought to emit radiation, and to decay as they do so - this is a weird one, but the explanation isn't too tough to understand... In quantum mechanics, even perfectly empty space is constantly bubbling with activity, as matched pairs of particles and anti-particles pop into existence for a brief period of time, then reconnect and annihilate each other. This is happening all the time, everywhere. But at the event horizon of a black hole, there's a possibility that the particle with the opposite charge of the black hole will be pulled in, and the other will be simultaneously repelled. Since opposites not only attract, they annihilate, that means the black hole is constantly losing some of its mass to these reactions, and releasing it in the form of particles with no connection, information-wise, to the matter that made up the hole itself (save charge and mass). It was bad enough when information was falling into the black hole and being trapped there, but to find out that it was also being permanently destroyed was a major crisis for quantum physics. The theory not only couldn't explain it, but major parts of it would have to be thrown out if it were true. And since we have, in fact, found evidence of Hawking radiation, quantum physics has a serious problem.
Has, or maybe had. "The Black Hole War" describes how at least part of the conundrum was resolved. A number of physicists (none with Hawking's PR department, sadly) developed a theory in which the event horizon was, itself, the black hole's entropy. If you've read something recently about the universe being a hologram, this is exactly the line of reasoning that's under discussion... The surprising result that all of the information that had fallen into the black hole might be preserved right at its perimeter lead to the even more surprising result that all information in the universe can be thought of as residing at *its* perimeter. (If you know what a nonogram, or Japanese Crossword is, it's an extremely helpful metaphor here). Hawking himself seems to have signed off on this theory, having paid off a $1 bet he made that the problem of black hole entropy would never be solved.
Which makes me wonder where this new theory of his is coming from... I'm not sure if he's just restating the work other people have done (wouldn't be the first time), or if there's some further difficulty he's trying to resolve that I'm not aware of. In any case, this doesn't mean anything like "there are no black holes" - there are, and there's likely one at the heart of every single galaxy, including our own. It just means they don't behave like the perfect geometrical fields of force predicted by relativity, but are rather stormy, complex, and, well, hairy things after all.
I really wish the title was reworded. It should be titled "Stephen Hawkings state Black Holes aren't as we know it" it's a lot more accurate and a lot less sensational.
The dude has taken a lot of heat over this statement for the very reason of headlines like this.
The dude has taken a lot of heat over this statement for the very reason of headlines like this.
Or at least, "There are no event horizons". At no point is the existence of black holes contested. Just the nature of those horizons. Even the event horizon itself is still there, it just isn't as absolute as traditionally thought if he is correct.Dragonbums said:
This would be like saying that the hula hoop is more oblate than round like we thought ergo the hula hooper does not exist. Wrong.
Interesting topic and one he'd know more about than most others. Will be interesting to see any more developments. Was a bit of a fan of Stephen Hawking till he turned out to be such a flagrant racist [http://www.bbc.co.uk/news/uk-22446054].
At this point it's too late.Lightknight said:
Every major science and media outlet out there has already used this misquote as their title heading. *sigh*
Shouldn't assume you understand something when in reality you have no idea. There will be no way to understand a black hole until we explore one. And that will never happen.
We'll destroy ourselves before we have the resources to explore space. We love money too much.
Oh, same goes for cyborg stuff. Costs way too much to make, common people will never get it. blah blah.
We'll destroy ourselves before we have the resources to explore space. We love money too much.
Oh, same goes for cyborg stuff. Costs way too much to make, common people will never get it. blah blah.
Maybe this is a bit more dramatic for you then?TomWiley said:
This is a Quasar. It is an active, feeding supermassive black hole. And the fact that it is so bright even though it is further away than most known galaxies should give you an idea of how energetic these things can be. You are basically looking down the "barrel" of a supermassive black hole.