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Earth might have hairy dark matter
But what happens when one of these streams approaches a planet such
as Earth? Prézeau used computer simulations to find out. His analysis found that when a dark matter stream goes through a planet, the stream particles focus into an ultra-dense filament, or “hair,” of dark matter. In fact, there should be many such hairs sprouting from Earth. A stream of ordinary matter would not go through Earth and out the other side. But from the point of view of dark matter, Earth is no obstacle. According to Prézeau’s simulations, Earth’s gravity would focus and bend the stream of dark matter particles into a narrow dense hair. Hairs emerging from planets have both “roots,” the densest concentration of dark matter particles in the hair, and “tips,” where the hair ends. When particles of a dark matter stream pass through Earth’s core, they focus at the “root” of a hair, where the density of the particles is about a billion times more than average. The root of such a hair should be around 600,000 miles (1 million kilometers) away from the surface, or twice as far as the Moon. The stream particles that graze Earth’s surface will form the tip of the hair, about twice as far from Earth as the hair’s root. Another fascinating finding from these computer simulations is that the changes in density found inside our planet — from the inner core, to the outer core, to the mantle to the crust — would be reflected in the hairs. The hairs would have “kinks” in them that correspond to the transitions between the different layers of Earth. Theoretically, if it were possible to obtain this information, scientists could use hairs of cold dark matter to map out the layers of any planetary body, and even infer the depths of oceans on icy moons. Earth might have hairy dark matter | Astronomy.com http://www.astronomy.com/news/2015/1...ry-dark-matter |
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Earth might have hairy dark matter
On Wed, 25 Nov 2015 12:50:03 -0500, Yousuf Khan wrote:
Earth might have hairy dark matter | Astronomy.com http://www.astronomy.com/news/2015/1...ry-dark-matter This is not likely because ANY significant presence of dark matter within or near the solar system would disturb the orbital stability. In other words, if significant amounts of dark matter were present among the earth and other planets, the stable orbits of the solar system would have been disrupted long ago. The stability of the solar system implies an upper limit on the local density of dark matter and such an upper limit is quite small. Thus the problem with dark matter is not just to explain its nature and composition but also to explain why it is so non-uniformly distributed within galaxies. |
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Earth might have hairy dark matter
Dear Lester Thorpe:
On Thursday, November 26, 2015 at 10:39:31 AM UTC-7, Lester Thorpe wrote: On Wed, 25 Nov 2015 12:50:03 -0500, Yousuf Khan wrote: Earth might have hairy dark matter | Astronomy.com http://www.astronomy.com/news/2015/1...ry-dark-matter This is not likely because ANY significant presence of dark matter within or near the solar system would disturb the orbital stability. Not if it were uniformly distributed. Of course this paper says the distribution might be displaced by collections of matter... which makes the problem you allude to. .... Thus the problem with dark matter is not just to explain its nature and composition but also to explain why it is so non-uniformly distributed within galaxies. Easy. It is primarily a "calibration error". But if we don't look for exotic matter too, it is not Science. David A. Smith |
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Earth might have hairy dark matter
On 26/11/2015 12:39 PM, Lester Thorpe wrote:
On Wed, 25 Nov 2015 12:50:03 -0500, Yousuf Khan wrote: Earth might have hairy dark matter | Astronomy.com http://www.astronomy.com/news/2015/1...ry-dark-matter This is not likely because ANY significant presence of dark matter within or near the solar system would disturb the orbital stability. In other words, if significant amounts of dark matter were present among the earth and other planets, the stable orbits of the solar system would have been disrupted long ago. The stability of the solar system implies an upper limit on the local density of dark matter and such an upper limit is quite small. Thus the problem with dark matter is not just to explain its nature and composition but also to explain why it is so non-uniformly distributed within galaxies. I have my doubts about this theory too, but in reality the amount of dark matter within the solar system must be minuscule, and very low density, not enough to disturb the orbits of the planets. Yousuf Khan |
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