Super-fast super-massive black hole spins at nearly light-speed NuStar – the X-ray telescope launched by NASA last year – is turning in its first science with measurements revealing that the outer edges of the NGC 1365 black hole are spinning at 84 percent of light-speed or more. The supermassive black hole in the NGC 1365 galaxy has a mass more than two million times that of the sun, but …
But the interesting question is, the Black Hole not being solid stuff but rather a spacetime edge, what exactly is "rotating at speed X" here? Is the maximum speed attained when the inner event horizon is as larger as the outer one? Will rotating any faster than c cause bad things to happen? MATH NAOW!
what exactly is "rotating at speed X" here?
The accretion disk. The article says that "the outer edges of the NGC 1365 black hole are spinning at 84 percent of light-speed or more."
Infalling matter follows the rules of relativity, so that in a relatively flat spacetime, by definition it can't travel at c or more, while in a degenerately curved spacetime (like falling into a black hole) it's red-shifted to such a degree that it will disappear from our relative view before it even appears to approach or exceed c (even before it hits the event horizon). It's just cosmic censorship in action.
give it a rest. The reg has its share of both readers and writers from a variety of nations. Some of us have different ideas about where to put c's and z's, or use er instead of re, or write o instead of ou. Who the fuck cares?
By the way, I think you'll find that Americans and their math have a fairly good record in space. Remind me when the last time was a British spacecraft, designed using proper maths, made it out of Earth's orbit?
Relativity would have it that as an observer approaches velocity c time dilates and at c time stops. This means that the observer cannot measure velocity and hence distance because there is nothing to measure it with, also the typical observer A observer B questions are not relevant because at velocity c there is no distance in a black hole and a singularity exists. Is this what the event horizon is?
One could argue that a singularity is where everything has the velocity c, that relativity has broken down and only quantum physics apply, further one could postulate that all the particles are entangled. As for exceeding c obviously not.
Imaging dropping a ball into a bottomless pit: the further the ball falls, the faster it gets. That's all that's happening.
So the rest mass of the infalling material doesn't change. However if we were able to put some of it on a set scales, then the inferred mass would be higher. But that's just the kinetic energy manifesting via E=Mc2 and it's only true while the particle is moving bloody fast, compared to us. You would get the same result from a falling ball, if it could be weighed in flight by a sensitive-enough set of scales.
From what I understand the speed of light does not apply to space time itself so it could possibly spin faster than the speed of light around the black hole (ie frame dragging but article does not say this however from what I understand). The article however is talking about in falling matter which can not exceed the speed of light.
Why yes, I can.
There's 2 ways in fact...
First is that em-radiation is a duality - can be thought of as a particle or a wave. Particles are subject to gravity but waves are not. Therefore it is possible for radiation to escape (as a wave) but no THING escapes.
The second is the way photons are generated is when electrons fall from an outer shell to an inner one within an atom. As matter passes the event horizon, the insane amount of gravity collapses atoms in on themselves, thus releasing huge numbers of photons. Some will happen to be released in the right direction (out) and with enough energy (x-rays) to escape and be detectable over here.
Well, it's near enough for an internet comment page. For a more accurate description you might like to find an advanced astrophysics textbook!
>> First is that em-radiation is a duality - can be thought of as a particle or a wave. Particles are subject to gravity but waves are not. Therefore it is possible for radiation to escape (as a wave) but no THING escapes.
That's just fully wrong. For starters it assumes that one knows how to combine Quantum Field Theory and General Relativity. NOPE. Then is assumes that "particles" are "things" but "waves" (which should properly be called "fields", unless there is ANOTHER confusion) are not. NOPE. NOPE. NOPE.
> For a more accurate description you might like to find an advanced astrophysics textbook!
For any accurate description, you will have to await development in theoretical physics.
Meanwhile, hand-waving and finagling indicates that there is "Hawking radiation" which rests upon the idea you can have a quantum state in which a matter/antimatter pair (of whatever, just keep the sum of quantum numbers zero) is being "produced" at the edge at the event horizon (i.e. checking for particles has a non-zero probability of coming back positive) but one of the particles "disappears over the horizon" (finagle, wink, wink), while the other is observed laters far away from it. As the interpretation "the black hole emitted a particle" fits the observed history, one can take that.
should be the best place to find exotic matter and other space-time detritus such as we haven't a hope of replicating here. If there is an anti-gravity particle or a sub-ether wave to be found and harnessed, this is the place- if they aren't, well the future is going to be boring as Earth slowly goes back to the stone-age.
Beer- for optimism...
What these people have found is very cool and will hopefully expand human understanding of the universe. I have to point something out us commentards though, according to theoretical physics it is possible to travel faster than c despite what you may think you know or have been told (http://www.theregister.co.uk/2012/10/10/ftl_special_relativity_mathematics/). A black hole, its accretion disc, or anything else, going faster than c is well within the realms of possibility, would be fascinating to find though.
You will also notice I used c rather than the speed of light, as anyone with any bases in science will know, you can separate white light into a spectrum and this must mean that the speed of light is dependent on its frequency and the medium it is traveling through.
@Sir Runcible Spoon
You may be joking, but there is tentative evidence to suggest that longer wavelength EM radiation (e.g. radio waves) may interact less with spacetime than shorter-wavelength EM radiation (e.g. light) leading to minute differences in the arrrival time of photons of different energies that have travelled billions of light-years. Such a thing has been measured...
This, of course has nothing to do with c not being constant, but instead to do with the structure of spacetime at very small scales (e.g. the Planck length) as predicted by certain unifying theories such as string theory.
The OP, of course, was talking bollocks.
I'm surprised no-one has mentioned this possibility (or impossibility, depending on quantum gravity and other physics we don't know much of). Wonder if there's any hope of learning more by studying this beast from the very great distance we're at.
http://en.wikipedia.org/wiki/Naked_singularity
I marvel at all the erudite comments posted as a result of this article. However, my big problem is: How does an x-ray telescope work? Don't x-rays just pass through it? And how do boffins know that the images produced on film(?) or CCD or whatever are the result of focused x-rays rather than photons of other frequencies/energies?
They work by 'grazing incidence', since x-rays can't be reflected back the way they came (like visible light in a mirror), but can reflect if the just barely graze the 'mirror'. They consist of a series of concentric paraboloids, with a common focus some way behind the mirror. Wikipedia
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