Scientists Discover Teeny Tiny Black Hole 277
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."
That's nothing... (Score:5, Funny)
(But who will be there to measure...?)
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Quantum Foam (Score:4, Informative)
Re:Quantum Foam (Score:5, Insightful)
The value of the Chandrasekhar limit depends on how one performs the calculation, but typically it comes out to around 1.4 solar masses (not 2.5). But actually, this is not so much the interesting question, because the Chandrasekhar limit applies only to white dwarfs, whose mass is supported by electron degeneracy pressure [wikipedia.org]. This is only one type of a much broader concept called fermion degeneracy pressure.
For example, a neutron star is much denser than a white dwarf, and is supported by neutron degeneracy pressure instead of electron degeneracy pressure and hence the Chandrasekhar limit does not apply to neutron stars. The equivalent limit for neutron degenerate matter is called the Tolman-Oppenheimer-Volkoff limit [wikipedia.org]. Like the Chandrasekhar limit, this calculation is very dependent on the behavior of the degenerate matter, but UNlike the Chandrasekhar limit, we know very little about the properties of neutron degenerate matter, and so the uncertainty of the T-O-V limit is quite large; it is usually placed (as you can see in the wikipedia article that I link to) between 1.5 and 3.0 solar masses. And there are even denser objects that have been proposed (though not observed) made of quark degenerate matter, and the limit on the mass of these things is even more uncertain.
So the point is, there is still a good deal of physics that can come from the observation of a 3.8 solar mass black hole, as it can constrain various models of fermion degenerate matter.
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Re:That's nothing... (Score:4, Funny)
But... it needs more string theory.
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001 = First black hole created by LHC
Some people are afraid the LHC-001 is going to destroy the Earth.
Oh shit... (Score:5, Funny)
Re:Oh shit... (Score:5, Funny)
Not to worry, the Enterprise is speeding around the Sun as we speak... Space-whales told them to.
Relax (Score:4, Funny)
Besides never apply a Star Trek solution to a Babylon Five problem. [starwreck.com]
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What the article fails to pont out is ... (Score:5, Funny)
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Re:That's nothing... (Score:4, Funny)
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Afraid? I'm praying for it! And Cthulhu. Which one comes first.
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Re:That's nothing... (Score:5, Funny)
Actually, nm, don't say it, it's too obvious....
I dunno, but... (Score:4, Funny)
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No, it isn't. Protons are stable as best as anybody can tell -- if their life time is finite, then it is many orders of magnitude longer than the life time of the universe. While the Hawking-life time of a proton-mass black hole is miniscule (they evaporate faster, the less mass they have).
Is it smaller than this one? (Score:4, Funny)
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Black Hole for our young planet (Score:2)
LHC countdown (Score:2, Funny)
Black-hole... sheds new light... (Score:5, Funny)
We weren't the first (Score:5, Funny)
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Re:We weren't the first (Score:4, Funny)
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http://en.wikipedia.org/wiki/Particle_accelerator#High-energy_machines [wikipedia.org]
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I know what you're thinking. Wouldn't it be cool to see a few office buildings crushed into a space no bigger than a pin head.
Sorry to burst your bubble.
http://en.wikipedia.org/wiki/Large_Hadron_Collider#Micro_Black_Holes [wikipedia.org]
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Awwww, little baby one (Score:5, Funny)
Size vs Age (Score:5, Interesting)
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At least, if I were a scientist and not someone pulling this directly out of my ass, that might be what is happening here.
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It would be really interesting if we eventually found a class of black holes which could only predate the big bang.
Re:Size vs Age (Score:5, Informative)
But!
The temperature of a black hole can be defined by the rate at which Hawking photons are streaming away from it. In the case of a black hole of a few solar masses, this temperature will be in the nano-Kelvin (I think -- don't hurt me if I'm wrong by a few orders of magnitude). Now remember everything in the Universe is sitting in a bath of cold photons from the Big Bang (i.e. the microwave background). These photons have a temperature of ~4 Kelvin.
Therefore, black holes whose Hawking temperature is above the microwave background will be net *gaining* mass.
Which is all a long way of saying, no, this isn't a normal size black hole that has decayed over time. It must have been created at this mass (or smaller).
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So the CMBR at 2.7 Kelvin is about 165 million times warmer than this black hole.
Now as an academic aside, assuming the universe doesn't end in either a big rip or a big crunch, but rather a disappointing heat death, eventually the matter and energy in the universe would be so diffuse due to ordinary expansion that the temperature would drop below that 16.4 nano-Kelvin, and the hole would start losing mass. Over probably close to a goo
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For a black hole of one solar mass (about 2 × 10^30 kg), we get an evaporation time of 10^67 years--much longer than the current age of the universe.
So even though this hole is evaporating like any other it could not have been much larger at the time of its formation (although it might have been somewhat smaller depending upon how much mass it has sucked in during its existence so far), even if it had existed since the beginning of the Universe which is impossible because stars, and especially lower mass stars like the one that mos
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Once that occurs, the black hole shuts down and it's simply a matter of time until it evaporates into nothing.
I believe the final thing that appeared to enter the hole and allow it to reach it's kill limit was a space cruise ship, Tita-something or other. Closely followed by an upper-class-looking golden robot. I t
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Perhaps you can answer a question for me. If I understand the concept correctly (and stop me where I go wrong), the event horizon can be defined as the point where any light that were to be ejected (I know, I know not possible) from the singularity perpendicular to the tangent (straight "up") would stop and return.
This is the Newtonian description of a black hole. The relativistic description is considerably more complicated. First of all, you must always start any relativistic description by stating your reference frame - i.e. who is making the observations? The Schwarzschild metric (which is the standard non-rotating black hole) takes the observer to be someone infinitely far away and not moving relative to the black hole. According to that observer, there is a singularity at the event horizon. Anything inside th
Goldilocks (Score:5, Funny)
When we find the most average, space bears will come and blast us into porridge.
Astronomy kicks ass.
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http://slashdot.org/comments.pl?sid=160059&cid=13397749 [slashdot.org]
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BEARS!!
http://www.livescience.com/space/scienceastronomy/080402-medium-black-holes.html [livescience.com]
Suggested new title for this... (Score:2)
untrue statement (Score:5, Interesting)
Theoretical limit is 1.4 Solar Masses (Score:3, Informative)
http://en.wikipedia.org/wiki/Chandrasekhar_limit [wikipedia.org]
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1.4 solar masses is much smaller than the masses we're observing for black holes. My point was we haven't approached this yet. There are other fo
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Mine was that the Chandrasekhar limit is important to any discussion on black holes.
>1.4 solar masses - possible black hole
1.4 solar masses - not enough mass to collapse the thing.
Now there is a way a black hole can form then lose mass - Hawking radiation.
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"this finding sheds new light" (Score:5, Funny)
Ob: stupid joke (Score:2)
Thank you, thank you - I'm here all week. The lasagna's great - tip your waitress...
RS
obligatory reference (Score:2)
Size does matter (Score:2, Funny)
It's not the size of your black hole that matters, it's how you manage your singularity.
pathetic (Score:2)
Atkins? (Score:2, Funny)
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Re:Probably Something Stupid (Score:5, Informative)
The mass of the black hole is the most defining characteristic.
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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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Re:Probably Something Stupid (Score:5, Informative)
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.
Re:Probably Something Stupid (Score:5, Informative)
It was this tear that lead, if I recall, to the original conjectures of a white hole, and the Einstein-Rosen bridge.
Rotating black holes [Re:Probably Something S...] (Score:5, Interesting)
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.
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.
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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".
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.
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.
Within the event horizon, any choice of coordinates is rather badly behaved, because there is no well-behaved stationary coordinate system.
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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'?
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it doesn't actually have a well-defined radius (since you can't measure across the middle!)
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 long
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I'm not making much sense of that.
How can it not make sense to measure the distance across it?
If you have two objects approaching it from either side starting from known locations and travelling at known velocities, is it not possible to determine when they reach it?
Since they start from known locations then the distance they travel to reach it is measurable.
Since you know the distance apart of
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Just a wild speculation. I'm not an expert on this.
If you are standing apart from the event, some light year(s) away, you can calculate the distance between objects by simple trigonometry. But if you are standing inside the event horizon... If there is no dimensions how can one measure distances? :)
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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.
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A point singularity would not be possible AFAIK (Score:2)
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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.
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Yes that's what astronomers mean when they say how "big" a black hole is.
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About 10^68 yr. Bring a book.
Bemopolis
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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.
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Not an easy thing to do when your antimatter has negative weight and the black hole has all but infinitely strong gravity.
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And just following that through... wouldn't that make the average density of a black hole zero? Mass/volume with infinite volume...
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Re:The Earth in danger from microscopic black hole (Score:4, Interesting)
"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 [physicsforums.com]
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
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because there's no "friction" on the black hole.
And you know this how exactly? I guess you might be talking about a micro black hole, maybe orders of magnitude smaller than an electron. In that case I would have to agree that the earth would seem to be mostly empty space, like a whole galaxy to a human sized spaceship. But if it is anything much larger than that I would imagine that there would at least be some frictional forces as it plummeted through the dense metallic core of the earth like a lead brick through air. If its mass were great enough I wo
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