A dark-matter experiment deep in the Soudan mine of Minnesota now has detected a seasonal signal variation similar to one an Italian experiment has been reporting for more than a decade.
The new seasonal variation, recorded by the Coherent Germanium Neutrino Technology (CoGeNT) experiment, is exactly what theoreticians had predicted if dark matter turned out to be what physicists call Weakly Interacting Massive Particles (WIMPs).
“We cannot call this a WIMP signal. It’s just what you might expect from it,” said Juan Collar, associate professor in physics at the University of Chicago. Collar and John Orrell of Pacific Northwest National Laboratory, who lead the CoGeNT collaboration, are submitting their results in two papers to Physical Review Letters.
WIMPS might have caused the signal variation, but it also might be a random fluctuation, a false reading sparked by the experimental apparatus itself or even some exotic new phenomenon in atomic physics, Collar said.
Dark matter accounts for nearly 90 percent of all matter in the universe, yet its identity remains one of the biggest mysteries of modern science. Although dark matter is invisible to telescopes, astronomers know it is there from the gravitational influence it exerts over galaxies.
Theorists had predicted that dark matter experiments would detect an annual modulation because of the relative motion of the Earth and sun with respect to the plane of the Milky Way galaxy.
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Gravity and the Scientific Method
Posted on April 18, 2011 Comments (4)
One of the topics I return to repeatedly is the scientific method – theories must to tested. As evidence mounts that new ideas do a good job of explaining theories they become more accepted. But they continue to be tested in new ways as the ideas are extended and ramification are explored. And science progress means that old conventions can be overturned as new evidence is gathered.
Science is not about current beliefs. Science is about seeking knowledge. If the search for knowledge leads to evidence that old ideas were wrong those ideas are overturned. Since people are involved that process isn’t as clean as it sounds above. People get comfortable with beliefs. They build careers on expanding those beliefs. Most are uncomfortable when they are challenged and don’t accept new ideas even when the evidence mounts. But some do accept the new ideas. Some challenge the new ideas by running experiments. And some of those prove the new ideas faulty. Some become convinced of the new ideas as the results of their experiments make the new ideas seem more sensible (instead of getting the results they expected).
Building the body of scientific knowledge is not nearly as clean and simple as most people think. It isn’t a simple process, what is the underlying truth can be debatable. But the beauty of the scientific process is how it helps us overcome our biases and provide evidence to support the theories we support. The scientific method (combined with our human involvement) doesn’t mean new ideas are accepted easily but it does mean new ideas compete on the basis of evidence not just the power of those that hold the beliefs.
Is gravity not actually a force? Forcing theory to meet experiments
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Categories: Research, Science
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