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Scientists Discover Teeny Tiny Black Hole
AbsoluteXyro writes "According to a Space.com article, NASA scientists have discovered the smallest known black hole to date. The object is known as 'XTE J1650-500'. Weighing in at a scant 3.8 solar masses and measuring only 15 miles across, this finding sheds new light on the lower limit of black hole sizes and the critical threshold at which a star will become a black hole upon its death, rather than a neutron star. XTE J1650-500 beats out the previous record holder, GRO 1655-40, by about 2.5 solar masses."
They say LHC-001 will be even smaller!
(But who will be there to measure...?)
Fears raised collider would create black holes that could swallow planet
Is this the point where they say we'll need to re-think our theories on black hole evapouration too? But first, let's switch on the LHC and see what happens...
HILARITY!
I see we weren't the first to build a large hadron collider.
It may look cute now. But they grow up.
While it may be possible that this black hole was formed from a relatively small (to form a black hole) star, couldn't it also be the case that it just a really old black hole? Hawkings told of how black holes can 'evaporate' over time with lack of surrounding matter, perhaps that could be the case here.
They measure it at where light can no longer escape its gravity, so they measure the "blackness".
Cheers, Jared
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So, we've now discovered the biggest and smallest black holes known to exist within about a week of each other.
When we find the most average, space bears will come and blast us into porridge.
Astronomy kicks ass.
While black holes is not my area, I can tell you that when someone talks about the size of the black hole, they refer to the event horizon, since you can't really measure anything going on inside it.
The mass of the black hole is the most defining characteristic.
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Would it be more correct to say this is a measurement of the event horizon?
Yes that's what astronomers mean when they say how "big" a black hole is.
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They can't figure out the "critical threshold" because there isn't one. It all depends on too many variables to set a universal limit (hehehe get it...universal :-P) It depends on how much nuclear activity there is still going on when it start collapsing and what the amount of heavier atoms is and the amount of other things orbiting the star and any other forces affecting the star at that time and how fast it's moving and spinning. Mass is a smaller part of the calculation than they're making it sound like. If they're going to factor everything in just to find some minimum mass, well duh, two particles and a hell of a lot of force. Haven't they suggested that in that big particle accelerator aka donut of doom. So yeah, a critical mass threshold doesn't exist.
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A black hole, conventionally, consists of an event horizon surrounding a region of space from which you can't send information to the external world. This region of space is not a point, it has a well-defined circumference. (Because of the non-euclidean nature of general relativity, it doesn't actually have a well-defined radius (since you can't measure across the middle!) but people usually just consider the radius as if it were defined as the circumference divided by 2 pi, and don't worry about the fact that you can't actually measure it.)
At the center of the black hole is, according to general relativity, a point singularity, which indeed has no dimensions.
http://www.geoffreylandis.com
I believe they are referring to the diameter of the event horizon
For those of you who haven't done any Astrophysics...
http://en.wikipedia.org/wiki/Chandrasekhar_limit
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What is the theoretical time before this black hole evaporates through Hawking radiation?
About 10^68 yr. Bring a book.
Bemopolis
"I guess the moral of the story is, don't paint your airship with rocket fuel." -- Addison Bain
INfinite.
A black hole of any stelar size will only radiate like a body in the femto-kelvin range.
This means that galactic background radiation will "refill" it more than it could ever lose.
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
Actually, that's only true of a non-rotating (or Kerr) singularity. All natural black holes will be rotating (the black hole maintains the rotational momentum of the pre-collapse mass). In a rotating black hole, the singularity is actually a ring (or torus). Inside that ring/torus, there is a tear in space.
It was this tear that lead, if I recall, to the original conjectures of a white hole, and the Einstein-Rosen bridge.
"Stumble before you crawl"
ok, I am ripping most of the info from here: http://www.physicsforums.com/showthread.php?t=122375&page=6
"If they were able to make a small blackhole, and it got "loose" and fell to the center of the Earth, the pressures at the Earths core would force material into it so fast that even a very small one would gobble us up very fast. I am not sure what the exact pressure is at the Earths core but it could force material through even a very small "hole" very quickly. I do agree that once it gobbled up the Earth, it would just continue to orbit the Sun, and the Moon would still orbit the blackhole as if it were the Earth..."
No, you should read this thread.
First of all, a black hole that falls to the center of the earth, wouldn't stop there, but would continue falling up on the other side, just to plunge in again, and on and on, because there's no "friction" on the black hole.
Second, there have been posted in this thread a lot of calculations of the speed at which it would gobble up matter.
Don't forget that the black hole we're talking about here IS MUCH MUCH SMALLER THAN A PROTON. As such, pressures on *atomic* level (such as in the center of the earth) matter little: the black hole travels most of the time in the empty space between nucleae.
A way to calculate the probability of hitting a nucleus (and somehow imagining that it would gobble up the entire nucleus, which is MUCH MUCH bigger than the black hole itself - which is a worst-case scenario) is done by calculating the "cross section" of the black hole and its probability to cross a nucleus on its voyages through the earth. We know its speed (just falling), and knowing the cross section and the density of nucleae, we can estimate how many nucleae it could eat per unit of time.
For a classical black hole, the calculation is done in the link provided by Pervect in this post:
http://www.physicsforums.com/showpos...4&postcount=12
for a MUCH LARGER black hole, about the size of a proton, weighting a billion tons (figure that! A black hole *the size of a proton* weights a billion tonnes ; we're talking here about black holes that weight 10 TeV or 10^(-24) kg - go figure how small it is !)
For more exotic calculations which are more severe, orion made some, and arrived at a time to eat the earth ~ 10^46 years.
All this in the following rather un-natural hypotheses:
- no Hawking radiation (which would make the black hole evaporate almost immediately)
- production of black hole EXACTLY IN THE CENTER OF GRAVITY of the collision (no remnant particles)
- very high production rate, producing billions of black holes per second.
I am not a physicist, but from what little physics I have had, and from reading threw the thread/flamewar, I dont think we have to worry about the LHC
Actually, the Schwarzchild solution does have a well-defined radius. In fact, the problem is that it has many well-defined radii, depending on what you mean by the term (as you point out, this comes about because of the non-Euclidean nature of the geometry). The commonly quoted "Schwarzschild radius" r = 2GM/c^2 is obtained by taking the area of the horizon and figuring out which "r" you would have to plug into A = 4 pi r^2 [true for a flat space sphere] to get the right result. Taking the circumference and dividing by 2 pi would achieve the same result. However, it is quite possible to figure out the proper distance between the horizon and the singularity by measuring the distance an infalling observer would travel. This distance is finite.
A problem can occur if you try and use constant time slices, using the "natural" time coordinate as defined by an observer far from the black hole. This gives silly results, but that is only because of badly behaved coordinates.
If that happens, what are we going to do!? Capitan Picard hasn't been born yet! Hell, even Kirk isn't around yet....
+1 IDisagreeSoHeMustBeATrollOrAnAstroturferOrAShill
Because Hawking was never wrong, right?
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This newly discovered Black Hole is the final result of a Large Hadron Collider, that caused a microsopic black hole on the third planet formerly circling the former star now known as 'XTE J1650-500'. So, this is not a naturally occuring black hole, but an alien-created one. Sadly this alien species is now extinct so they can't tell us how to avoid their mistake.
No, actually it doesn't. What is usually called the Schwartzschild "radius" is not actually a radius by the definition of the word, "distance to the center".
In fact, the problem is that it has many well-defined radii, depending on what you mean by the term (as you point out, this comes about because of the non-Euclidean nature of the geometry). The commonly quoted "Schwarzschild radius" r = 2GM/c^2 is obtained by taking the area of the horizon and figuring out which "r" you would have to plug into A = 4 pi r^2 [true for a flat space sphere] to get the right result.Exactly. You can calculate the area (which is well defined) and divide it by 4 pi, and you are free to call that the radius if you like. Or, equivalently, divide the circumference by two pi. But you can't measure the distance to the center.
Taking the circumference and dividing by 2 pi would achieve the same result. However, it is quite possible to figure out the proper distance between the horizon and the singularity by measuring the distance an infalling observer would travel. This distance is finite.Finite... and timelike. It would be a little like trying to define the radius of a circle if you're standing on the circumference, and the center is next Tuesday at noon.
A problem can occur if you try and use constant time slices, using the "natural" time coordinate as defined by an observer far from the black hole. This gives silly results, but that is only because of badly behaved coordinates.Within the event horizon, any choice of coordinates is rather badly behaved, because there is no well-behaved stationary coordinate system.
http://www.geoffreylandis.com
Why do you need to measure *across* the middle to measure the radius?
Is there a (theoretical) problem with using some kind of high tech space calipers to measure the radius without going anywhere near the 'middle'? You could, but the result wouldn't really be right. A black hole is like that blessed +2 bag of holding that has much more room inside it than the space that it actually encompasses. I never really studied general relativity, but I think that when an object is in a strong gravity field, it becomes shorter (or everything else becomes longer). This means that the notion of length gets a bit weird. Similarly, if you used calipers to measure the diameter of a block hole, the sides of the calipers would no longer be straight, as they got closer to the black hole, due to the way gravity bends space.
I hope I'm not totally wrong about this... I'm working from an analog of special relativity, which I did study a little...
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Well, maybe. Actually, rotating black holes radiate away angular momentum, and they also preferentially eat material that reduces their angular momentum, so it's an open question as to whether real black holes will be rotating. Probably, because the accretion disk is likely to be rotating, and it swallows up the accretion disk and gains the momentum from it, but I'm not sure you can necessarily say that all natural black holes will rotate.
In a rotating black hole, the singularity is actually a ring (or torus). Inside that ring/torus, there is a tear in space.It was this tear that lead, if I recall, to the original conjectures of a white hole, and the Einstein-Rosen bridge.
Actually, the Einstein-Rosen bridge comes from the maximum analytical extension of the Flamm embedding, way predating the Kerr solution. (It's a very trivial embedding, z = sqrt(r). The extension is z = plus or minus sqrt(r).) Turns out that the extended Flamm embedding is misleading, and a Schwartzschild black hole isn't a wormhole after all. But that wasn't obvious.
http://www.geoffreylandis.com
There are going to be a near-infinite number of quantum-scale black holes and wormholes in whatever volume of space you care to imagine. They evaporate almost instantly. As for stellar black holes, the Chandrasaker Limit is 2.5 solar masses, with a relatively small margin of error. Absolutely nothing of interest will be learned until we're within 2.75 solar masses, because then we can define sensible confidence limits on what the value actually is.
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as long as Stephen Hawking is still alive, I am sure he can handle it. After all Stephen Hawking beat all the other great scientists in poker with Commander Data in the far future, so he should be smarter than Picard or Kirk. If anyone knows how to reverse a black hole it would be Hawking.
Besides never apply a Star Trek solution to a Babylon Five problem.
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I'd love to know XTE J1650-500's secret. I've tried diet and exercise, but I'm still only down to 3.9 solar masses and 16 miles across.
Sure you can measure what's going on past the event horizon of a black hole. All you have to do is make your camera's velocity exceed the force created (or rather possessed) by a photon going at the speed of light, and presto! You now have a camera that can probe farther into the gravimetric field of a black hole than light by itself.
Unless you're one of those General Relativity literalists. *shudder*
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Sorry to break this to you, but you are rather mediocre at technobabble.
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Sorry, but no. It's called black hole evaporation, and black holes lose energy (hence mass), through this mechanism.
What you've described is a way that energy can be created from nowhere. If what you suggest were right, we'd all be doomed, as any small black hole would get bigger through Hawking radiation, and would then consume everything.
From the objects' points of view, they don't know when they cross the event horizon.
From an observer's point of view, the objects never reach the event horizon. They just appear to move slower and slower.
Black hole's really do mess up any concept of Euclidean distance. The best way of picturing it, is that it is a hole in space-time; for all intents and purposes, the space inside the event horizon simply doesn't exist.
for those wanting to find the article later, I strongly suggest Slashdot's own search instead of googling for the words "teeny", "tiny", "black" and "hole" :|
That I don't fully understand (IANAQP), but this link gets me part of the way.
In short, and with suitable hand waving, absorbing a positive energy regular particle of a virtual pair without absorbing the negative energy particle would break the Heisenberg uncertainty principle.