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Dark Matter Particles May Have Been Detected
During two seminars at Stanford and Fermilab on Thursday, researchers described signals for two events detected deep in an old iron mine in Minnesota that might mark the first detection of dark matter — or not. The presenters said the chances that the signals they detected were caused by something other than "neutralino" dark matter particles was 23 percent. "One source indicates that we'd need less than 10 total detections within the CDMS' range in order to have a high degree of confidence in the results." The NY Times describes the Cryogenic Dark Matter Search methodology: "The cryogenic experiment is nearly half a mile underground in an old iron mine in Soudan, Minn., to shield it from cosmic rays. It consists of a stack of germanium and silicon detectors, cooled to one-hundredth of a degree Kelvin. When a particle hits one of the detectors, it produces an electrical charge and deposits a small bit of energy in the form of heat, each of which are independently measured. By comparing the amounts of charge and heat left behind, the collaboration’s physicists can tell so-called wimps from more mundane particles like neutrons, which are expected to flood the underground chamber from radioactivity in the rocks around it." Here are the research team's summary notes of the latest results (PDF).
As a 49 yo feminist grandmother, I reject these results, since they are done by an old boys network of grey haired caucasian scientists.
Something with no energy means it has no movement. No movement means it must radiate all of its energy as gravitation.
So, what you're saying is that something with no energy must lose all of its energy as gravitation. Anybody else see a problem with this explanation?
Modding "-1, Troll" is not a proper response if you disagree with me. Try reason.
No, 1:4 is enough for a good argument. They need 1:1000 or lower to end the argument.
Rethinking email
Because scientist's interpretation of what they see is never wrong! When did science start to feel more like religion to me...
So tell me where they went fairy tale on us here?
Here is just a gross simplification, so I may not be completely accurate, but I fail to see where this is fairy-tale science.
Characterization: Isn't that where we are finding that galaxies aren't behaving as we expect them to, and that behavior is in the form of gravitational interactions which shouldn't happen given the amount of mass which we can see.
Hypothesis:
There is something there which for some reason has a lot of mass, but we can't see it. Literally: Dark Matter
Deduction: If Dark Matter is weakly interacting as is suggested by the fact that we can't currently see it. If we are able to detect an interaction which cannot be accounted for among known particles, you have either discovered dark matter, or some other particle altogether if that detected particle is not massive enough when combined with the rate of interaction and the mass of the detected particle.
Experimentation:
Stick a detector way down in a mine shaft which will help filter out a lot of things which could cause a false positive. Look for interactions which do not match any known possible interactions.
Again, that is grossly simplified, but I don't see the jump in logic you are looking for.
Out of modpoints but really liked a post? 1BDkF6TtmmeZ3yqXbz9yhdYVqRYnwFoXDj
All detected particles are due to abnormal solar activity.
The detected particles will melt the crust within the next three years. Buy tickets for the arch from me now! Just 1.000.000 Euro each... No checks
CU, Martin
P.S. Guess which movie i watched yesterday :-)
The country that falls behind in basic research is the country that falls behind in history.
It appears from a quick Google search that the University of Minnesota is funding it. I guess you're against NASA, too, but in favor of pouring trillions down the Iraqui quagmire?
WTF are you doing on slashdot? Trolling?
Free Martian Whores!
So by reducing the temperature of the sensor to half a degree Kelvin, they have reduced the energy level of the sensor to almost nothing. Yes, it interacts with incoming particles, but it also radiates gravitational waves that could be misinterpreted as external particles. In essence, the detector is detecting itself.
Of course, there is a 23% chance I am completely wrong.
There's a 100% chance you're wrong. Gravitational waves can't be absorbed by these detectors in any meaningful way. To notice the effects of even massive gravitational waves you need a huge detector (like LIGO). Also, gravitational waves happen when a gravitational field changes. They propagate this change through the universe. Objects at rest aren't emitting gravitational waves.
If you isolated these sensors from the universe and let them sit for a long time, they wouldn't lose their mass to gravitational radiation - they'd probably sit around until death by baryon decay in 10^33 years.
And no, they're not detecting baryon decay either.
"I zero-index my hamsters" - Willtor (147206)
The paper pre-print will appear on the arxiv as 0912.3592, but is already available as on the CDMS homepage. Two events or 23% seems a bit low for all the hysteria... Pentaquarks went away after 50 events were discovered at more than 10 different labs...
If you're ever in the neighborhood, a tour of the mine and the lab are well worth the visit.
http://maps.google.com/maps?q=Soudan,+mn
http://www.dnr.state.mn.us/state_parks/soudan_underground_mine/index.html
http://www.dnr.state.mn.us/soudan/physics_tour.html
(Generally open June-September -- check before you come.)
Dark matter != anti-matter. Turn in your geek credentials.
> I watched maybe too many star trek episodes...
You did.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
That's dangerously low!
My home town nearly went to zero Kevins back in 1978.
It was a particularly cold winter, and we were already down to 3 Kevins (due to their low popularity at the time).
Kevin Thomas had flown out to be with his son's family for a wedding and got stuck in Boston for a whole week due to the weather. 2 Kevins left.
Kevin Lemmer was rushed to the hospital during my shift. I still remember the call from the EMTs as the ambulance was rushing toward us. "It's Lemmer. He's in bad shape. Drove right into the fucking ditch." We called the time of death at 6:15 PM.
At 6:16, all eyes turned to room 2217. Kevin Spencer was 82 and on his death bed with leukemia. His family being Catholic, he had already been given his last rights. If he couldn't hold out until Kevin Thomas returned, we would be at zero Kevins. Sure, we had 4 perfectly healthy Calvins, but they're just not the same.
It was 7:15 when Carla Brooks and her husband James burst through the main entrance. "She's not due for 2 weeks!", James exclaimed. As the staff bustled around getting the Brookses settled, they exchanged darting glances with each other. This was their first child, and they wanted to keep the baby's sex a secret. Of course, in a small town, secrets don't get kept. Nearly all of the hospital staff new that the child about to rip open Mrs. Brooks was indeed a boy.
The delivery was routine, and Kevin Brooks was born healthy, if a tad underweight, at 10:52 PM. Kevin Spencer was pronounced dead at 10:54.
It was, as they say, a close one. Kevin Thomas arrived two days later, the weather having finally cleared up. To this day, we still rib him about it.
Cedar Falls is currently at 5 Kevins.
The only comment I have to make in the other direction is that I am uncomfortable with the probabilities that scientists have suddenly started to give - "there's a 77% chance we are completely correct".
Except it's not even that.
There saying there's a 77% probability that the result was not due to random noise, and that they actually did detect particles that are within the range predicted for neutralinos by Supersymetric Theory. Does that means it's a neutralino? Not necessarily, but it is a pretty strong argument of the "hypothesis -> experimentation -> verification" variety. Does it mean that everything they predict for neutralinos is true, or that Supersymetric Theory is "completely correct"? No.
I wish for some good old scientific conservatism, and the need to put percentages on the proportion of 100% correct you are feels a bit dubious.
Again, they're only putting a percentage on this not being a null result. Your characterization is wrong.
They're being conservative. But they're excited. And when you take a theory as ridiculously successful at making predictions as the Standard Model, make a logic extension to it and then that theory quite possibly has had its first verified prediction, that's not unreasonable.
I remember when scientific skepticism on slashdot involved people taking issue with specific aspects of the experimental procedure. Not people complaining that they don't like the result or how snooty the scientists are using statistics to measure their success.
The enemies of Democracy are
Exactly! I keep telling people; Einstein was wrong! An absolute speed limit makes no sense because there's no way I can understand how that would work!
Do you have the email of the president of physics?
That's because your logic is fundamentally flawed. If you were really questioning, and not just accepting everything at face value, you would say this:
Characterization: Isn't that where we are finding that galaxies aren't behaving as we expect them to, and that behavior is in the form of gravitational interactions which shouldn't happen given the amount of mass which we can see.
Hypothe- err, fuck that, I mean PROOF:
It's God. Literally God!! He's got his hand in that galaxy like it was a Jeff Dunham puppet.
Deduction: If God is weakly interacting with the galaxies, all you heathen sciency evolution types are fucked! Richard Dawkins won't be able to save you from getting cornholed by fire demons for the rest of eternity.
Experimentation:
Invoke the spirit of Charles Darwin. Ask him how hot Hell is. Fall on your knees, and hear the Angels sing. Never question God or me again. Now I will call you saved, please deposit $200 into the jar.
That's how you really fight the dogma of science.
Copypasta
http://hardware.slashdot.org/comments.pl?sid=1429380&cid=29967482
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Do what thou wilt shall be the whole of the Law