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Author Topic: Could dark matter be neutrinos?  (Read 975 times)

Offline thedoc

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Could dark matter be neutrinos?
« on: 07/08/2015 17:50:01 »
Kevin asked the Naked Scientists:
   
Dark Matter: cosmologists say there is a whole lot of matter in or around galaxies that cannot be directly observed. Physicists have identified bosons called neutrinos which are virtually impossible to detect. Why could the missing matter not be massive clouds of neutrinos around galaxies - thus no need for the dark stuff?
Kevin

What do you think?
« Last Edit: 07/08/2015 17:50:01 by _system »


 

Offline chiralSPO

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Re: Could dark matter be neutrinos?
« Reply #1 on: 07/08/2015 17:59:58 »
aren't neutrinos fermions?
 

Offline evan_au

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Re: Could dark matter be neutrinos?
« Reply #2 on: 08/08/2015 02:35:27 »
It is certainly true that there are lots of neutrinos in the universe - in fact there are billions passing through every square centimeter of your body, every second. These come from nuclear reactions in the Sun, and there are billions of stars in our galaxy alone, plus other neutrino sources like supernovae, and almost certainly the Big Bang.

Astrophysicists know the distribution of neutrino energies from the Sun, and they have even captured 24 neutrinos from a supernova in 1987.

It is hard to measure their mass exactly, but the neutrino has a very small mass. Because of its very high velocity (close to c), it would not remain bound to galaxies as Dark Matter seems to be. For these reasons, cosmologists believe that there are not enough neutrinos in the universe to account for the visible effects of Dark Matter, so they are continuing to search for other, more massive (and lower velocity), Weakly Interacting Massive Particles (WIMPs).
 

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Re: Could dark matter be neutrinos?
« Reply #2 on: 08/08/2015 02:35:27 »

 

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