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Simulations Predict Where We Can Find Dark Matter
p1234 writes with this excerpt from the Max Planck Institute for Astrophysics:
"Simulations by the Virgo team show how the Milky Way's halo grew through a series of violent collisions and mergers from millions of much smaller clumps that emerged from the Big Bang. ... If Fermi does detect the predicted emission from the Milky Way's smooth inner halo, then it may, if we are lucky, also see gamma-rays from small (and otherwise invisible) clumps of dark matter which happen to lie particularly close to the Sun. ... The largest simulation took 3.5 million processor hours to complete. Volker Springel was responsible for shepherding the calculation through the machine and said: 'At times I thought it would never finish.' Max Planck Director, Professor Simon White, remarked that 'These calculations finally allow us to see what the dark matter distribution should look like near the Sun where we might stand a chance of detecting it.'"
We discussed a related simulation a few months ago.
Don't bother reading the paper. They discovered that they could find dark matter "in space" if it exists.
Did you read the same article I did? Before this simulation their best guess was to look at other galaxies and target their centers. However, the simulation revealed that they have a better chance if they look at our own galaxy, but 10-30 degrees of center, where they should be able to detect gamma rays caused by dark matter.
N-body simulations require a high degree of communications between processing nodes, something "@home" systems don't provide.
Anytime the underlying assumptions of a computer input or algorithm are faulty, even the 3 1/2 million hours of computation on a supercomputer will not lead to the discovery of the scientific truth. The principle of garbage in garbage out still applies. The bottom line is simple: the dark matter emperor is as naked as a newborn.
They have a theory about how dark matter should work. They expended 3.5M hours of computing to make a prediction based on that theory. Now they'll try to confirm the prediction empirically. If the prediction doesn't pan out, the theory will be jettisoned or patched. If the empirical observations agree with the prediction, the theory is left standing until such time as new evidence shows it to be squidgy around the edges. That's how science works.