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Black Hole Observed by X-Ray Satellite
eldavojohn writes "Scientists at JAXA and NASA used the Japanese Suzaku satellite to collect data and observations at a distance nearer to a black hole than we've ever been. From the article: 'The observations include clocking the speed of a black hole's spin rate and measuring the angle at which matter pours into the void, as well as evidence for a wall of X-ray light pulled back and flattened by gravity. The findings rely on a special feature in the light emitted close to the black hole, called the "broad iron K line," once doubted by some scientists because of poor resolution in earlier observations, now unambiguously revealed as a true measure of a black hole's crushing gravitational force.' Suzaku also has been providing images and data of super novas and their activities. It's always nice to see national space agencies working together, it almost gives me hope that the world might one day be united in space exploration."
"Nothing for you to see here. Move along."
The grass is always greener on the other side of the light cone.
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam
It's a place to start. Every nation has scientists that are specialists in their own field, if we can get together and share information about space, imagine the possibilities.
That which does not kill me only postpones the inevitable.
What good would worrying about a black hole do? It's not like we can push it away...
Then isn't it just a star in a different frequency?
Could we consider our own sun a Yellow hole since we cannot see into the middle of it?
liqbase
Holly: Well, the thing about a black hole - it's main distinguishing feature - is it's black. And the thing about space, the colour of space, your basic space colour, is black. So how are you supposed to see them?
not only is that why they didnt notice it, but confirms exactly what parent is saying.
Why does no-one ever discover giant kittens at the centre of galaxies? Or that dark matter is made out of candyfloss? I need more comforting science, dammit!
Given that the black hole is a few zillion light-years from earth, I don't think that this satellite is much closer to it than anything ground-based. But the satellite has a much clearer view of the black hole (or at least, of its event horizon) without the atmosphere in the way, and that's what the press release means by "closer to the edge".
Strictly speaking, we have no knowledge about what happens inside the event horizon - we can't, by definition. However, we know the forces are extremely strong at the event horizon, and they'd only get stronger as it collapses still further, and we know of no force that would stop the collapse, so the logical conclusion is that it collapses to infinite density.
Well, maybe YOU can't push it away...
Taking guns away from the 99% gives the 1% 100% of the power.
In case you're interested in what the K-Iron broad line is check out http://arxiv.org/abs/astro-ph/0212065 and http://web.mit.edu/newsoffice/2005/spacetime.html
In some sense, you have to trust that physicists know what they're doing. Absent an understanding of the math, it really is an act of faith that black holes are not one big practical joke.
That being said, you may remember the Exclusion Princple from high school chemistry, which basically says particles like electrons and neutrons can't occupy the same (quantum) states. When you try and push them together, they push back. It is possible to calculate the maximum force (pressure actually) that such a system can produce. After that, there's nothing can keep a star from collapsing.
If you're interested in reading, check out "Electron degeneracy pressure" in an undergrad quantum mechanics textbook or on the Wikipedia.
Actually, you could. Get a massive object on the opposite side of the black hole. Get it close enough that you can maintain a thrust that will keep you at a steady point relative to the black hole. Make sure thrust is angled so it will not "strike" the black hole.
Using this process, gravity will pull the black hole away.
Now, this would take one hell of a lot of energy to do, but it is possible.
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Good question. Short answer: we don't know.
Long answer: According to the General Theory of Relativity, black holes have all their mass contained in a geometric point called the "singularity". This singularity is surrounded by a finite-sized spherical boundary called the "event horizon" which is defined as the locus of points where not even light can escape the gravity of the singularity. Because nothing (that we know of) can travel fast than light, the event horizon is a seemingly impenetrable barrier to any investigation of the singularity itself.
So we're unlikely to view a singularity directly and measure its size. On the other hand, most physicists are convinced that the General Relativistic description of the singularity as a literal geometric point most be wrong. They believe this because very small objects are governed by quantum mechanics, and a new theory (which does not exist yet) called "Quantum Gravity" must take over at densities like those found in singularities.
I'm generally a fairly skeptical chap, and it took a long time to even convince me that event horizons exist. For the longest time, all "proofs" of black holes basically said "here is something that is more dense than a neutron star, and since the ONLY THING more dense than a neutron star is a black hole, this object must be a black hole." I was never really convinced that there weren't other objects denser than neutron stars that didn't actually have event horizons, so this argument never swayed me. These recent observations seem to conclusively prove that event horizons exist, but singularities are an entirely different matter. We'll have to wait for the final word on that subject...
The MCG -6-30-15 paper referred to in the press release. I don't think the MCG -5-23-16 paper has been made public yet.
The most interesting thing about the paper is that Suzaku's Hard X-ray Detector (which operates in a comparatively poorly studied waveband) is consistent (based on the model of an accretion disc around a spinning black hole) with what's happening in the softer X-ray band.
Slashdot - Mutual Assured Discussion
'No space between the smallest particles' is basically what a neutron star is. It's essentially a mass of neutrons edge to edge, held up by the quantum-mechanical requirement - the exclusion principle - that no two particles can occupy the same quantum state.
However, there's a limit to this state. In general relativity, mass isn't the only thing that produces gravity: pressure does too. Pile on extra mass to a neutron star and its gravity increases - and so does the internal pressure. The upshot is that the pressure approaches infinity at about five solar masses; the neutron star can only collapse (the actual limit may be much lower, last I heard it wasn't precisely known).
Thus if general relativity is correct there's nothing that can prevent the total collapse of a five-solar-mass neutron star. Propose a force that can resist it, and it can only do it by upping the pressure still further, and hence the gravity it must oppose... The star collapses to zero volume and infinite density, the notorious singularity hidden inside the event horizon.
All that said, though, it's probable that the star does not reach zero volume. General relativity is known to be unreliable on the very small scale of quantum mechanics, and quantum mechanics is known to be unreliable where very large masses are concerned, so the applicable physics when you compact five solar masses to a volume smaller than an atom is anybody's guess...
Real Daleks don't climb stairs - they level the building.
A black hole is not a literal physical singularity. There are "bigger" ones and "smaller" ones. It is instead a mathematical singularity: it can be treated as a point object in the sense that if you lay out a gravitational grid across the universe, each black hole is a point, a hole on that grid where nothing comes out.
So why do black holes emit X-rays and Hawking radiation or why do they emit stuff at all?
The black holes don't emit anything per se. However, as particles close to the event horizon are accelerated more and more by the gravitational pull of a black hole, THEY can emit radiation. An illustrative model is a star/black hole binary system in which gases from the star are being pulled in to the black hole, thus emitting X-rays as they are accelerated.
Hawking radiation is also not really emitted from the black hole itself. Theory goes quantum fluctuations occur so close to the event horizon that one particle gets sucked in while the other escapes: imagine a positron-electron pair appearing right on the cusp of an event horizon. Let's say the positron disappears into the black hole while the electron escapes out into the universe. From our perspective, the electron will have been "emitted" from the black hole. The energy required for this is also taken from the black hole as the positron (think of it as negative energy) will go into the black hole and take that much energy away from it.
"The Cube": it just wouldn't be the same without fellatio "Corey Kosak": It just wouldn't be the same... oh, looks like
PhysicsPhil has a pretty good explanation. Here's another way of phrasing it.
Electrons, neutrons, and so on don't really exist as volumes, but rather as forces. Think about a balloon filled with air; it takes up space, but the only reason it does is because of the pressure of the air inside pushes out on the surface.
Now, if you squeeze the balloon, it'll shrink. The more you squeeze, the smaller it gets. If you could squeeze as hard as you please, you can continue to shrink the balloon smaller and smaller.
Particles are like that. Gravity is unique in that it's a force that can get infinitely strong, so it can overcome any other force, and squeeze everything together down to an arbitrarily small point.
Interestingly, from the perspective of a star collapsing into a black hole, it never actually quite makes it, as time slows down as gravity becomes stronger. It's like Zeno's paradox: If you try to go from point A to point B, crossing half the distance each time, do you ever get there? Intuitively, you'd think no, but if you take an infinite number of steps, yes.
In other words, black holes, from the perspective of the black hole, take forever to collapse down to a singularity. However, from our perspective outside the black hole, the singularity forms essentially instanteously, as our subjective time speeds up relative to the black hole's subjective time.
(As a side note, we don't have a theory of quantum gravity, so we don't actually know what the absolute center of a black hole is like, but we do understand the physics up to and past the event horizon, all the way to the singularity, all of which is just subject to general relativity. All the effects with astronomical significance occur outside the event horizon, as information that goes past there is effectively meaningless.)
they invented the Sudoku satellite. But what does that have to do with black holes?
If this is your plan, then it would not matter whether it orbited or not. You could just throw it in the event horizon. Wouldn't matter.
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Wrong branch of science. You might try a major pharmaceutical company or your local drug dealer instead.
I Am My Own Worst Enemy
More bullshit whiney rhetoric from the left.
What in that sentence gave you the impression that the author even supports high taxation of the rich to fund comprehensive public services, let alone workers' control of the means of production?
At any rate, you seem to have overlooked the word 'always' in the sentence, which strongly implies the existence of other cases of international cooperation in space. Such cooperation is always nice to see. Or perhaps you think it's a bad idea?
Real Daleks don't climb stairs - they level the building.
You could just throw it in the event horizon
Are you sure? I thought about that and it just didn't appear obvious to me, although it would make sense, I just thought making them a binary system was a safer bet.
You just got troll'd!
It's conventional to treat the event horizon as the surface of the black hole - in which case, yes, it has a shape. The mathematically simplest black hole is the Chandrasekhar black hole, which is nonrotating and spherical. Realistically, however, a black hole will be formed by the collapse of a star, and conservation of angular momentum implies that it will be spinning very rapidly, at least to begin with. This is the Kerr black hole, and it has some very peculiar effects on the region of spacetime around it. There's a zone called the ergosphere, from which it is possible to escape, but in which it is completely impossible to stand still...
Real Daleks don't climb stairs - they level the building.
The momentum of the system is the same regardless of the configuration of the system..
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The basic principle is that things are spinning. In the case of a galaxy, the whole thing would originally have formed from a collapsing gas cloud. This cloud would have had some small overall spin, which would be magnified during collapse by conservation of angular momentum (try it yourself: hold a brick in each hand, spin around and around as fast as you can with your arms outstretched, then quickly pull in your arms and hold the bricks to your chest...) So you've now got a smaller ball of gas which is spinning quite fast. Now it should be obvious how it flattens out: the spin stretches it at the equator, gravity collapses it at the poles, and before long you've got a disc.
As for black holes, that's spin again, but it works a little differently. Black holes are so powerful that they drag space itself around with them, and infalling matter really has no choice but to fall in line over the equator...
Real Daleks don't climb stairs - they level the building.
it almost gives me hope that the world might one day be united in space exploration
I guess you missed yesterday's story documenting the US' clear intention to be the single entity with control over access to space; 'The policy calls upon the Secretary of Defense to "develop capabilities, plans, and options to ensure freedom of action in space, and, if directed, deny such freedom of action to adversaries."'
Personally, I like the idea of cooperation towards a goal. It seems to improve the chances that we'll stay awhile. Heck, ISS has been manned for something like five years.
Interestingly, from the perspective of a star collapsing into a black hole, it never actually quite makes it, as time slows down as gravity becomes stronger.
No. Time flows normally from the perspective of the star. It's for the outside observer that time appears to slow down (it never really would appear to *stop* it would just approach infinitely slow.)
But for a hypothetical observer on the star, time would appear to proceed normally. Also, if I'm remembering right, for the star observer the *rest of the universe* would appear to slow down, as well, if there was some way to observe it. (I know that applies to high-percent of c velocities but can't remember if it applies to gravitational effects as well)
*snark*