Slashdot Mirror
NASA Achieves Breakthrough Black Hole Simulation
DoctorBit writes "NASA scientists have achieved a breakthrough in simulating the merging of two same-size non-spinning black holes based on a new translation of Einstein's general relativity equations. The scientists accomplished the feat by using some brand-new tensor calculus translations on the Linux-running, 10,240 Itanium processor SGI Altix Columbia supercomputer. These are reportedly the largest astrophysical calculations ever performed on a NASA supercomputer. According to NASA's Chief Scientist, "Now when we observe a black hole merger with LIGO or LISA, we can test Einstein's theory and see whether or not he was right.""
From the article: "when two massive black holes merge, all of space jiggles like a bowl of Jell-O"
Wouldn't Kraft Foods have prior art on this?
"Itanium chips actually get used"
The catastrophic results of merging Microsoft and Linux?
The hilarious results of merging Intel and AMD.
The unexpected results of merging a spinning Steve Jobs (Intel is Evil/Intel is the best, brightest, future of Apple) and the O'Reilly No-Spin Zone.
Those I'd buy tickets for.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
What kind of framerate do you get on that machine when playing Half-Life 2?
...would he have developed General Relativity sooner, or just played WarCraft?
--- Attorneys Assisting Citizen-Soldiers & Families -
Based on observations, what percentage of black holes are non-spinning vs spinning?
Now when we observe a black hole merger with LIGO or LISA, we can test Einstein's theory and see whether or not he was right.
And if he's wrong then all the scientists can make "loser" signs at him on their foreheads...
Summation 2
And even more likely: Whether or not the computers performed the calculations correctly (the chips are made from Intel, and we all know the history of Intel screwing up floating point math)
Non spinning black holes?
Is there such a thing?
Democrats or Republicans. They are both taking us to the same place and they are not afraid of us anymore.
Not mentioned in the article of course, is that shortly after the simulation, the software collapsed in on itself as it underwent a Massive Total Existence Failure.
Watching massive things merging.. jiggling like jell-o... Good heavens, space is a pervert!!!
Slashdot Burying Stories About Slashdot Media Owned
I don't know about you, but I already give enough of my money to publicans on a Friday night...
"I Know You Are But What Am I?"
OK, I'm no general relativist, but I am a computational physicist -- what could the article possibly mean when it says earlier attempts were "plagued by computer crashes -- the equations were far too complex"?
I can imagine a situation where a poorly-arranged computation of an equation might give you an underflow in an intermediate result, or where a badly-arranged summation might give you noise. But crashing the computer? Sounds more like array-bounds, which can happen no matter how simple the equations are.
2*3*3*3*3*11*251
What is the actual outcome from this research?
more knowledge about the universe and how it might work.
Will this help create more energy-efficiency in the world?
maybe, who can say what future developments and understanding of this area of physics will bring.
Will it help us find technology that humanity can actually use to make a better society?
maybe, see above. it depends on the definition of "better".
when general relativity was first thought of in 1915 there was no application, for the average person. today GPS relies on general relativity.
Will it increase our safety, or decrease power of madmen and dictators?
the obvious answer is probably not. and while these are important questions, this one is not topical in this discussion.
--meh--
How about making science progress by testing a part of one of the most important theory in physics? It's not my funding, however I'd love my country to invest more in science even if only for the sake of science. We're in an era where everything has to be justified by money, it feels like the Dark Age of information. I'm waiting for the next era where new thoughts, science and knowledge progress get some value back.
Call me utopist if you want, but finding something that "increase our safety, or decrease power of madmen and dictators" gets the #1 naive award (always thinking big shields and weapons, what a world).
And I whole heartily encourage all patent and IP lawyers to go to those black holes and ether Subpoena them or deliver a notice of possible infringement.
This should solve all lot of problem here on earth as well, if we can get them to all go.
Unless that is the Black hole decides to show up for its court date.
HL2 is singlethreaded so the performance would be the same as on one Itanium. Also x86 code has to be emulated on Itaniums = slow. Oh and no GPU which means pixel/vertex shaders would have to run on software. Educated guess: 0.1 fps.
That's nothing--the WB and UPN are merging in September, producing a vortex of TV so sucky that not even brain cells will be able to escape.
The interesting question is whether the CW black hole will rotate or not. I for one hope that TV execs will be able to sit on it and spin.
GCHQ Quantum Insert installed. If only our tongues were made of glass, how much more careful we would be when we speak
You use his theories to construct and run a model, and then you compare the results of that model to what you can observe in the sky. The differences between what is observable and what the model indicates are where the new knowledge is, even if things don't match up.
I'm a recent member of this group, so I'd like to put in my 2 cents.
:) (some competing groups use Cactus which is C++ based, although it also allows C and Fortran).
1) This is a first -- no other group has achieved this before. yay! (after decades of work!)
2) This is hard for the following reasons:
a) since you are doing calculations near (or on/in) a black hole, you tend to get a lot of
infinities, which 1) crash your code and 2) exacerbate your errors
b) for most simulations, your grid remains fixed. For black holes though, they *deform* the
spacetime around them -- which means your grid points have to move (in a non-predictable
manner)!
c) what happens when two black holes merge is not well understood (ie, what should happen?),
so this is new science
d) initial data is hard to get and unreliable. If two black holes are far apart, you can
write an exact solution (at least within some error), but to get them close to where they
are interating, you pretty much need this kind of simulation anyways. This is such a large
problem that there are only a handful (a dozen or two?) initial data sets currently.
3) Everything is written in Fortran!
4) It runs on a variety of architectures (x86, Itanium, PA-RISC, Alpha, etc etc)...pretty much
anything that supports ifc (faster) or gcc.
5) There are several approaches to some of the issues above, from puncture splitting (using a
different spacetime metric like 1/r vs r to remove the singularity), excision (not evolving
inside the event horizon, since that's not "interesting" anyways), and other methods. Our
new method actually doesn't need any of those "tricks", which is pretty interesting.
6) This data helps drive the LISA and LIGO projects from a theoretical standpoint--basically
knowing what kind of gravitional waves they should be seeing, and to correlate what they see
and what their data may represent (ie, if you see a waveform like this, this means that it's
two merging black holes, vs just co-rotating black holes).
6a) We study black holes b/c they are pretty much the only thing that'll generate detectable
gravitational waves.
so yay!
"You have the option of insanity. I do not. And that makes me crazy!" - Brian to Angela, My So-Called Life