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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.
This is not a field I am really into, but I wish them the best of luck finding the dark matter.
I wonder if dark matter to them is like a Ubuntu release to most of us?
I can't believe no one has tried looking for dark matter directly next to the Sun. That should light it up!
Just look in Nibbler's litter box.
Instead of a gamma-ray glow map as seen from the Sun, I'd like to see 3d renderings of a whole galaxy where they artificially color dark matter to show where it is.
Sounds like with that many computer hours needed they should set up something similar to Seti@home
It's only paranoia if your wrong...
hours to predict, if it only took the computer that long what took them so long to figure this out.
that sounds a pretty useless measurement
my mid range processor does about 0.5GFLOPS, which means those available on the market probably range from about 0.1-2GFLOPS give or take, and then theres graphics processors, which are capable of TFLOPS these days, so there could be a factor of about 10^4 in the number of FLOP's done, i know that astrophysics often has order of magnitude calculations, but that's just a bit useless
I find plenty of dark matter when I turn out all the lights prior to going to bed for the evening.
Specifically, I find plenty of dark matter with my toes, which doesn't result in a shout of discovery like, "Eureka!" but ,"*$&#@!"
LAUNCELOT: Look, my liege!
ARTHUR: Camelot!
GALAHAD: Camelot!
LAUNCELOT: Camelot!
PATSY: It's only a model.
ARTHUR: Shhh!
Ezekiel 23:20
Rofl
... also knows where it can find dark matter. And it doesn't need teraflops to do so !
Votez ecolo : Chiez dans l'urne !
NIGGER OWNERS MANUAL
Congratulations on your purchase of a brand new nigger! If handled properly, your apeman will give years of valuable, if reluctant, service.
INSTALLING YOUR NIGGER.
You should install your nigger differently according to whether you have purchased the field or house model. Field niggers work best in a serial configuration, i.e. chained together. Chain your nigger to another nigger immediately after unpacking it, and don't even think about taking that chain off, ever. Many niggers start singing as soon as you put a chain on them. This habit can usually be thrashed out of them if nipped in the bud. House niggers work best as standalone units, but should be hobbled or hamstrung to prevent attempts at escape. At this stage, your nigger can also be given a name. Most owners use the same names over and over, since niggers become confused by too much data. Rufus, Rastus, Remus, Toby, Carslisle, Carlton, Hey-You!-Yes-you!, Yeller, Blackstar, and Sambo are all effective names for your new buck nigger. If your nigger is a ho, it should be called Latrelle, L'Tanya, or Jemima. Some owners call their nigger hoes Latrine for a joke. Pearl, Blossom, and Ivory are also righteous names for nigger hoes. These names go straight over your nigger's head, by the way.
CONFIGURING YOUR NIGGER
Owing to a design error, your nigger comes equipped with a tongue and vocal chords. Most niggers can master only a few basic human phrases with this apparatus - "muh dick" being the most popular. However, others make barking, yelping, yapping noises and appear to be in some pain, so you should probably call a vet and have him remove your nigger's tongue. Once de-tongued your nigger will be a lot happier - at least, you won't hear it complaining anywhere near as much. Niggers have nothing interesting to say, anyway. Many owners also castrate their niggers for health reasons (yours, mine, and that of women, not the nigger's). This is strongly recommended, and frankly, it's a mystery why this is not done on the boat
HOUSING YOUR NIGGER.
Your nigger can be accommodated in cages with stout iron bars. Make sure, however, that the bars are wide enough to push pieces of nigger food through. The rule of thumb is, four niggers per square yard of cage. So a fifteen foot by thirty foot nigger cage can accommodate two hundred niggers. You can site a nigger cage anywhere, even on soft ground. Don't worry about your nigger fashioning makeshift shovels out of odd pieces of wood and digging an escape tunnel under the bars of the cage. Niggers never invented the shovel before and they're not about to now. In any case, your nigger is certainly too lazy to attempt escape. As long as the free food holds out, your nigger is living better than it did in Africa, so it will stay put. Buck niggers and hoe niggers can be safely accommodated in the same cage, as bucks never attempt sex with black hoes.
FEEDING YOUR NIGGER.
Your Nigger likes fried chicken, corn bread, and watermelon. You should therefore give it none of these things because its lazy ass almost certainly doesn't deserve it. Instead, feed it on porridge with salt, and creek water. Your nigger will supplement its diet with whatever it finds in the fields, other niggers, etc. Experienced nigger owners sometimes push watermelon slices through the bars of the nigger cage at the end of the day as a treat, but only if all niggers have worked well and nothing has been stolen that day. Mike of the Old Ranch Plantation reports that this last one is a killer, since all niggers steal something almost every single day of their lives. He reports he doesn't have to spend much on free watermelon for his niggers as a result. You should never allow your nigger meal breaks while at work, since if it stops work for more than ten minutes it will need to be retrained. You would be surprised how long it takes to teach a nigger to pick cotton. You really would. Coffee beans? Don't ask. You have no idea.
MAKING YOUR NIGGER WORK.
Niggers are very, very averse to work of
Due to the proximity to the Sun, the Galactic centre is the brightest and most extended source. This makes it easier to detect than any of the small dark matter subclumps that are distributed over the sky. If one of them should also be detected, it may be devoid of any stars.
I'm interested in that last sentence. Does the gamma radiation push away hydrogen and dust, preventing the formation of stars, or does dark matter exhibit a repulsive gravitational force, clearing a region of space around it? Without referring to Wikipedia, the latter seems unlikely, but the former seems like something we should worry about. How much gamma radiation are we talking about? Should we worry about one of these clumps drifting near the solar system and sterilizing everything? (And if so, how much of an effect would these clumps have on the Drake equation?)
Nothing for 6-digit uids?
This assumes that dark matter generates gamma rays, a form of electromagnetic radiation. Has anybody ever scientifically demonstrated that it is possible to generate such electromagnetic radiation by means OTHER than moving electrical charges?
You are quite correct. They are making a huge assumption that dark matter can annihilate with itself. Whether it can do this depends on the type of dark matter - in some models it can in others it cannot. This is not pointless though - their work will either see it or at least put a limit on how well it does annihilate which we may be able to use to give us a better idea where to look at the LHC.
One way to avoid having charges produce photons is to have your particle partly consist of the EM field. For example, although the experiment has never been done, I think (if you are a particle theorist feel free to correct me!) you could annihilate two Z bosons to give two photons because the Z consists partly of an EM field.
If they do detect such gamma radiation, how will they ascertain that this radiation is NOT caused by an electrical phenomena rather than some unknown action of undiscovered dark matter?
When you have an annihilation like this the photons produced are mono-energetic. Hence you will get a large spike in the emissions at a particular energy value. Since dark matter has a mass in the 10's of GeV minimum (for most models) this would be extremely hard to produce by other means and certainly not in a mono-energetic fashion. Of course, this is not concrete proof that it comes from dark matter but if all the physics we know about cannot explain it then it would have to be dark matter or something else completely new.
they already found some dark matter under Uranus.
I wonder how many days 3.5 million processor hours actually is. I run SETI@home still, I wonder if that's comparable.
We can either dig virgon 6 or farm niblonians, whichever floats your boat.