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Modeling Supernovae With a Supercomputer
A team of scientists at the University of Chicago will be using 22 million processor-hours to simulate the physics of exploding stars. The team will make use of the Blue Gene/P supercomputer at Argonne National Laboratory to analyze four different scenarios for type Ia supernovae. Included in the link is a video simulation of a thermonuclear flame busting its way out of a white dwarf. The processing time was made possible by the Department of Energy's INCITE program.
"Burning in a white dwarf can occur as a deflagration or as a detonation. 'Imagine a pool of gasoline and throw a match on it. That kind of burning across the pool of gasoline is a deflagration,' Jordan said. 'A detonation is simply if you were to light a stick of dynamite and allow it to explode.' In the Flash Center scenario, deflagration starts off-center of the star's core. The burning creates a hot bubble of less dense ash that pops out the side due to buoyancy, like a piece of Styrofoam submerged in water."
Which is why it's called a simulation. Who the heck modded this insightful?
blimey, i was expecting them to use prayer, because that has been proven to work unlike these so called 'computers', which according to Ben Stein the nazi's used
I'm a rabbit startled by the headlights of life
Probably someone who actually knows what simulation means.
Simulation is something which simulates a system or environment in order to predict actual behavior.
To speculate on the other hand is to make an inference based on inconclusive evidence; to surmise or conjecture.
So, he was indeed insightful when he stated that the lack of understanding would render the results speculative at best.
(all definitions courtesy of wikitionary)
If sharing a song makes you a pirate, what do I have to share to be a ninja?
Imagine a pool of gasoline and throw a match on it.
like a piece of Styrofoam submerged in water
Now I know what to do with myself on this slow Sunday morning.
I bet he could make a neater looking explosion without the use of a super computer. It'd even have audio!
maybe, just maybe, it might pack enough grunt to play crysis
Well, I'm a pyromaniac and I consider this stimulation.
You are also testing the math formula with this, if the visualized model looks different to what can be seen in nature, the formula is flawed. If it looks similar to nature it probably is a good model.
....to see the BlueGene explode in flames from all the complicated calculations....hope to see this on youtube!
You guys are missing the point of the modeling. You don't always model something to make predictions of its actual behavior. In this case modeling serves as an excellent way to test our models against empirical data collected from observations of supernovae. So, we do our best to construct a model, then compare this model to the real system in order to expose holes in our understanding of the phenomenon. This is good science.
SRSLY.
there wouldn't be any point in simulating this if we knew everything about them. it's a step on to better understanding of what is going on.
Sigs are too short to say anything truly profound so read the above post instead.
A little over a third of the way through s02e09 of The Universe here has these guys talking about their simulation.
So if you have a model and you run what you think is a simulation and then it turns out that the prediction from your model was incorrect, you should have been calling your simulation speculation?
How is that not just hair splitting semantics?
Nerd rage is the funniest rage.
What are processor-hours, exactly? I don't think it's utilization of the supercomputer for x-amount of hours, since that would mean they've booked the computer for almost 42 years.
we understand little about it and the math formula used will be a half guess. supercomputer or not, results will be speculative at best.
I don't think you understand how experiments work... If the results of the computations are something other than what is observed in nature, then the methods and/or equations are proven wrong. That is most certainly a NON-speculative result.
Just because the model shows a burst of star stuff blowing out this way or that way in some particular configuration doesn't mean that scientists will leap up from their chairs and say "Stars do this, and we've proven it."
You can never know if your models are correct. All you can do is continually test them and try to prove them wrong. Maxwell's equations have not been proven to be correct -- they've just never been shown to be wrong. This simulation is just a step on the path of evidence.
Agreed, I don't understand why more people don't see that. It's through simulations like these that we test our theories about the universe. Wasn't it computer simulations of galaxies that led to the discovery of dark matter? If we already perfectly understood the physics of supernovae, there would be no need to run the simulation in the first place.
The path to enlightenment is truly through homemade drugs!
I thought this story sounded familiar. Then I clicked the link, and lo and behold, there's the exact same video I remembered watching a year ago. I double checked -- the video was dated March of 2007. So why is this just now making headlines? I could understand if they re-ran the simulation with new physics that proved to be more accurate or something, but why link to the old video?
The path to enlightenment is truly through homemade drugs!
troll much?
"I don't think you understand how experiments work" sounds like you are making an assumption as well
Not to mention several "PhD life spans" probably were spent on even programming this model and testing it in every way possible. No this is not speculative at best, this is a huge opportunity to actually test what we know against reality which is the point of this kind of theoretical science! Now if you please some of us have science to get back to, your welcome to continue to yell foul from as far away as possible.
Mo00o
was I the only one who initially read the headline as "Modeling Supermodels with a Supercomputer"?
Mr. Hu is not a ninja.
There are several steps in constructing useful models and the last, and most controversial is that of "model validation".
In building a computer model/simulation, you generally follow these steps:
1) problem formulation - what do you want to figure out, gather data, get the "reference behavior pattern"
2) formulate a mental model of the system - what are the entities involved and how are they related
3) build and debug your model
4) verification - this is where you ensure the model behaves as expected against specific sets of inputs - as you change inputs, does it do what you expect (I turn up the volume knob - and the sound gets louder)
5) validation - this is where you compare the results of the model with the reference data from the real world. If it doesn't match, you then have to back up and figure out what's wrong... was the implementation of the model incorrect? were your initial hypotheses incorrect? And if it does match, have you gathered enough real world data to know your model is functioning well? How confident are you of this model's ability to model the system you're interested in.
So suppose you've built a model that you can validate against gathered data, you still have to demonstrate that your model is valuable to the scientific community.
You're probably going out on a limb to make strong assertions when a model demonstrates/predicts behavior that has not been observed. However, it can serve a great role in helping determine what other things to look for, what conditions may exist, or help see relationships that you may not have seen before.
The controversy is over how much you can use a model to help prove a hypothesis.
I think Scientific Modeling in a compute cloud is more sexy, since it is way cheaper than 42 millions of processor hours and allows spikes. If one doesn't see differences between lab grid and cloud, go read wikipedia or http://groups.google.ca/group/cloud-computing/browse_thread/thread/73e1030b18df3730?hl=en
Does anyone have any implementation level details about this? I'd love to hear what the software approach is, what programming language they'll be working in, how the parallelism will be handled, what sorts of problems are involved etc etc etc. We come here for news for nerds (well, cool graphics are OK too, but...)
We just need continually improving ways to make those excess cycles available.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
"Modeling Supernovae with a Supercomputer controlled by the Aperture Science Supercolliding Superbutton"
I modeled a Type 1A at home by taking an old 74LS00 IC and hooking power and ground up to a neon light power supply. I yelled "Don't cross the streams!" and flipped the switch. Glowing fragments flew in all directions, proving the inversion of the event horizon and validating my work in the field of glowing-particle physics.
There seems to be some quantum effect component also, because right after the simulation, my landlady appeared and went supernova too!
Just junk food for thought...
And here I thought that supernovae would be modeled by a supermodel.
Correct me if I'm wrong, but haven't we not actually found any dark matter yet?
"the phenomenon that the majority of the gravitational effects within galaxies are unaccounted for, but are now commonly attributed to some kind of 'invisible matter'" just seemed like too much to write. Alas, I ended up writing it anyway.
The path to enlightenment is truly through homemade drugs!
Hookers are cheaper than models, and almost always do what you expect!
"I don't think you understand how experiments work" sounds like you are making an assumption as well
I'm not assuming anything. I've formed a model based on the evidence.
Just wondering if this will lead to an alternative energy source, like building a dwarf star under the hood. That would cost about as much as a tank of gas anyways.
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
...stop 'exploding', do a 360 degree revolution, and carry on exploding. Are the physicists sure they have this right? I don't think that kind of process could preserve angular momentum, not to mention the vast amounts of energy that seem to be held at bay for significant periods of time.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.