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NASA Achieves Breakthrough Black Hole Simulation
Posted by
ScuttleMonkey
on Wed Apr 19, 2006 10:28 AM
from the pretty-pictures dept.
from the pretty-pictures dept.
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.""
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IP violation (Score:5, Funny)
Wouldn't Kraft Foods have prior art on this?
Yes. (Score:5, Funny)
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.
Re:IP violation (Score:3, Funny)
This is the USPTO we're talkin about here.
Cheers.
Finally.... (Score:2, Funny)
Headline should read: (Score:5, Funny)
How about something more useful? (Score:5, Funny)
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.
They did do something useful (Score:2, Funny)
They finally managed to use up all of those Itanium processors hang
I think what we really want to know is... (Score:5, Funny)
Meh (Score:4, Informative)
If Einstein had had those supercomputers ... (Score:5, Funny)
Re:If Einstein had had those supercomputers ... (Score:2)
Re:If Einstein had had those supercomputers ... (Score:2)
There are two kinds of physicist (Score:2, Informative)
There are theoreticians. Einstein was a theoretician. He asked relatively simple questions and followed the logical consequences. I suspect that having to use a computer would
Re:There are two kinds of physicist (Score:2)
Nope. The guys who run these simulations are all theoretical physicists and/or mathematicians. The various forms of Einstein's equations suitable for simulation on a computer
Re:There are two kinds of physicist (Score:3, Insightful)
Re:If Einstein had had those supercomputers ... (Score:2)
Oh come on! This is Einstein we are talking about
He'd be playing "Red Alert: Command and Conquer"
Re:If Einstein had had those supercomputers ... (Score:2, Insightful)
It is important to have self-awareness that this is an issue and put hard-line limits on things, including drinking or playing a game. "I will only play 3 hours a day" or "I will st
Are there non-spinning black holes? (Score:4, Interesting)
Re:Are there non-spinning black holes? (Score:5, Informative)
Re:Are there non-spinning black holes? (Score:5, Informative)
Re:Are there non-spinning black holes? (Score:3, Informative)
Re:Are there non-spinning black holes? (Score:3, Informative)
Once they have some experience with this simulator I'm sure they will move on to spinning black holes.
True. In fact, some steps have already been taken in this direction by other groups. For instance, my group at U.T. Brownsville -- whose non-spinning simu
Non-spinning black holes?! (Score:2)
Must've been playing Nowhere Man [lyricsfreak.com] in the background when they came up with this idea.
And if Einstein is wrong... (Score:5, Funny)
And if he's wrong then all the scientists can make "loser" signs at him on their foreheads...
translate article (Score:3, Funny)
Are they really testing what they think? (Score:5, Insightful)
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)
Re:Are they really testing what they think? (Score:2)
Re:Are they really testing what they think? (Score:5, Informative)
First, with regard to intel, there is essentially no risk from this, as the math libraries used by everyone involved in such work wave test exercises that verify the accuracy of the hardware. It's not uncommon to run every calculation on two physical processors to assure that no single processor malfunction can introduce a significant error.
Second, with regards to the correct approximation of Einsteins equations, either the approximation is exact, in which case there is no risk, or the error size for the approximation is closely known, in which case when we observe the black hole merger, we will have one of 3 conditions: confident to some error size that he was right (actual results match simulation, but we can't rule out his theory being slightly wrong at a finer level), confident that he was wrong (actual results lie outside of error range for simulation), or no result (actual results indicate the possibility he was wrong, but lie within error range).
That's new to me. (Score:4, Interesting)
Is there such a thing?
Re:That's new to me. (Score:2)
Is there such a thing?
Can a single point spin?
Although, I don't know if the center of a black hole is more than a single point
Re:That's new to me. (Score:5, Funny)
OAQ (Score:5, Funny)
Ick! (Score:4, Funny)
Watching massive things merging.. jiggling like jell-o... Good heavens, space is a pervert!!!
For the last time folks, they're not black holes! (Score:2, Funny)
A Long HIstory of Calculations (Score:3, Interesting)
Larry Smarr, "Gravitational Radiation from Distant Encounters and Head-On Collisions of Black Holes: The Zero Frequency Limit," Phys. Rev., D15, 2069-2077, 1977.
I cite this paper because Larry Smarr is one of the Nasa panelists for this project, and I heard his talk on this paper at the University of Texas at Austin in the late 1970s. Come to think of it, I remember seeing one of the other panelists, Joan Centrella, at the same talk.
Equations too complex? (Score:5, Interesting)
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.
Re:Equations too complex? (Score:5, Informative)
the propagation of
describes the time evolution of a tensor for which all the
components are not independent- for instance they obey
Bianchi identities.
http://mathworld.wolfram.com/BianchiIdentities.ht
Simple numerical integrators destroy these identities
at order dt^n for some small but finite n. Run the code
forwards and one can find finite time blow ups due to
the stepping algorithm- however even after a single
time step the numerical solution has unphysical aspects
Finding
http://www.ima.umn.edu/nr/abstracts/6-24abs.html [umn.edu]
Black hole simulation (Score:4, Funny)
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.
From a member of the group (Score:5, Informative)
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!
Re:I bet... (Score:2)
Re:Wasted funding? (Score:3, Funny)
Re:Wasted funding? (Score:2, Insightful)
Exempli gratis (and it's way out there):
Using this new data, someone observes a black hole merger. It doesn't fit the data. Relativity is redone, so to speak. Someone sees a great way to unify Relativity and qu
Re:Wasted funding? (Score:5, Insightful)
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.
Re:Wasted funding? (Score:3, Insightful)
Re:Wasted funding? (Score:5, Insightful)
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).
Re:Wasted funding? (Score:2, Insightful)
Re:Wasted funding? (Score:3, Informative)
Re:OK... Wait... (Score:4, Insightful)
Re:OK... Wait... (Score:3, Insightful)
Re:OK... Wait... (Score:3, Insightful)
No. In Physics a theory makes claims that can be falsified by an experiment. The theory (general relativity) is already there and the experiments will b