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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.""
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)
Simulation means nothing with validation.
I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
People with addictive personalities will find something to be addicted to.
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 stop playing at midnight". Hard stops are usually easier to deal with than "I won't play too much" as that leaves too much open for interpretation, which is bad if you have an addictive personality.
The game isn't the issue.
This sig is the express property of someone.
What is useless now will someday be useful.
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 quantum mechanics because of the new formulation. Bam. Like that, unified theory of everything. Those spinning superconductors generating magnetogravitic fields are understood. Artificial gravity and anti-gravity are discovered. Moon-flights are near cheap after a while. Etc. etc.
Saying "I don't see any results coming out of this tomorrow so this research is useless" is about as shortsighted as one can get. It's akin to foreign aid: sure, it gets us little immediate benefits, but the long-term stuff can really pile up.
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).
I realize that this doesn't fit nicely into your libertarian view, but we often do science just for the sake of doing it. Knowledge in and of itself is a good thing, and funding some cycles on a computer that would otherwise be simulating nukes or finding prime numbers doesn't seem wasteful to me at all.
Observationalist observe nature. Observationalists are like experimentalist, but the nature of their work precludes controlled experiments. They make observation of the natural world - the Earth, the Sun, planets, or stars - but they don't always have the luxury of observing the same phenomenon in the same conditions repeatedly.
Simulationist run computer simulations of natural phenomenon and interpret their results. The techniques necessary to do this are quite different from those that are needed to do pure theory.
Of course their is some overlap in these categories, with many physicists doing at least some work that would fit into more than one category. Other people might divide things into more than four categories, but I would say that it is pretty clear that all of the physics being done these days does not fit into either experiment or theory anymore.
Preventive War is like committing suicide for fear of death. - Otto Von Bismarck
You can't do meaningful experiments without some idea of what the theory says will happen. Numerics of this sort provide that for complex physical cases which are essentially impossible to work out with pen and paper. So yes, this is a step towards getting knowledge of the universe and how it might work.
Also, understanding does NOT require the tie to experiment since you can have mathematical understanding of a particular theory independant of whether that theory properly models reality. For instance, I can go and work out what orbits look like in a five dimensional space. If I go and check my results versus reality 'hey, it doesn't match up!'. So from that point of view, all I've learned is that space on that scale isn't five dimensional. But lets say I don't even bother to check versus reality. I've still learned something about the mathematical properties of the theory and I've gained intuition about how things behave - namely, I've learned that closed (classical) orbits seem to only be able to exist in 3d. How strange! And I've learned that if I had a situation where the system was, say, restricted to a lower dimension (examples in electromagnetism) then I can expect large changes to the dynamics. Or perhaps a better example is, we can learn a lot about phase transitions in three dimensions by doing problems in four dimensions where they can be solved exactly and then doing an expansion around the four dimensional solution to approximate the solution in 3d. That approach doesn't depend on the underlying Hamiltonian you're solving being the correct one for some physical system - it is a purely mathematical understanding which can generically be applied to many different theories. So the benefit is, in the future when I find a better Hamiltonian for my phase transition, a better dynamical theory for gravitation, etc, I can apply the techniques I've learned from before to those as well.
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.
The key here is not really what the model looks like. It's how the model compares to real life. If when LIGO comes online, they detect waves that match what the model predicts they should detect, that gives experimental support that the equations the model is based on are correct. Also, in your example the equation is part of the theory, which is that 7=13, so then the model is 7*2 and the result is 26. If you do an experiment with counting blocks and combine two groups of 7 blocks yet find yourself with 14 blocks instead of 26, you should conclude that your theory is incorrect.
This analogy is kind of clumsy because you're essentially attempting to redefine the meaning of numbers, then directly compare the results of operations under the original number definitions. I think an equivalent situation would be to define an orange as an apple, then ask why, when I show you both an apple and an orange (according to my definitions), the two objects in my hand are different.
A better example is to theorize that gravity is proportional to mass (g = G*m1*m2/r^2). You can build a model based on this equation where the gravitational attraction between two masses at a certain distance with the known gravitational constant works out to be 2 Newtons. Then you can actually get the two masses, hold them r meters apart, and measure the force required to keep them apart. If it's 2 N, your theory looks good (it's not technically proven, but it's one step closer). If you get, say 1.9 Newtons, there are several possibilities: you theory is wrong (in this case we know it's right as far as classical physics is concerned), you made the model wrong (ie, you suck at math), or there were other factors influencing the experiment that you failed to account for (perhaps friction in your scale).
Won't building a model based on an equation automatically prove a theory that is based on that equation?
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 be carried out by LIGO and LISA (the latter having been delayed indefinitely thanks to Bush's plans).
However, we strongly assume that General Relativity must break down at some point and give way to some theory of quantum gravity. There are several such theories and we simply don't know which is correct, if any. So if one of these experiments showed a deviation from general relativity that would be very exciting.
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