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To: spunkets
Since they are non-interacting otherwise, they fly right through the Earth unhindered.

Have they 'caught' any?

The force of gravity is only large on Earth, because of the mass of the Earth

So this 'dark matter' stuff should be orbiting, or falling to, Earth and landing on my carpet. Eventually after billions and billions of years at least 'some' of the stuff should have been captured by Earth or Jovian or solar gravity.

I just don't buy the argument that solar gravity is too weak to trap this 'dm' stuff. After all this time there should be some of this crap relatively close to us. It can't only be 'out there'.

L

28 posted on 08/29/2007 9:14:56 AM PDT by Lurker ( Comparing moderate islam to extremist islam is like comparing smallpox and ebola.)
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To: Lurker
There's several neutrins detectors. They're in deep mines like Canadian gold mines. Neutrinos have been studied for quite some time. For decades there was a problem understanding the neutrinos that came from the Sun. There are 3 types. The wrong type of neutrino was observed coming from the Sun. The type of neutrino expected from solar hydrogen fusion was not observed in the right quantity. Later it was shown that the neutrinos can convert between types post reaction and the solar neutrinos were all accounted for.

"So this 'dark matter' stuff should be orbiting, or falling to, Earth and landing on my carpet."

They fly at the spped of light. The escape velocity from Earth's surface is ~11000m/s. The speed of light is 3*108m/s. They'll always fly back off into space. Neutrinos can interact with nuclear matter, so they can interact. Their small x-section means they have a low probability of doing so. So, if they do inteact, it's always deep in the Earth as they fly through. Axions just fly through.

"or Jovian or solar gravity."

Larger objects are required to capture them into orbit. It's the collection of large objects in a galaxy, or black hole that can and does.

29 posted on 08/29/2007 9:36:59 AM PDT by spunkets ("Freedom is about authority", Rudy Giuliani, gun grabber)
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