Is dark matter thought to be out in space somewhere or intermingled throughout the universe, including Earth?

3 comments

If dark matter makes up 96% of the universe, and visible matter only 4%, then is there dark matter around, on, or in the Earth or is it all out in space somewhere?

Comments:

George is close. Dark matter exists in large halos which envelope galaxies. The dark matter halos can have an arbitrary shape, in fact many people have made “maps” of the dark matter by looking at gravitational lenses. The size of the halo can be a few to many tens of times larger than the galaxy which resides in side of the halo. Many very large halos can host several galaxies (though rarely more than a few galaxies per halo).

The mistake George makes is when he says that it’s “near the Galactic center”. This is very false. The galactic center is *inside* a dark matter halo. In fact, the center of the halo and the galaxy need not be the same, such as in the case of this galaxy cluster:

http://en.wikipedia.org/wiki/Bullet_Cluster

Also, since the dark halos host galaxies, and earth is in a galaxy, then earth is in a dark halo. Therefore, dark matter *EXISTS* all around us, even here on Earth. There are several major experiments set up to detect dark matter and measure it’s properties. You can learn about a famous experiment at:

http://en.wikipedia.org/wiki/Cryogenic_Dark_Matter_Search

{ 3 comments }

goerge f

No, dark and visible baryonic matter makes up around 4% of the mass; the rest is non-baryonic matter, which is about 23% of the universes mass; there is a 73% gap that is believed to be filled by ark energy,

Dark matter is thought to exist mainly in globular clusters, near the galactic center.

SteveDave

There is none on earth. Although i’m not entirely sure why i’m afraid.

orpheus_sword

George is close. Dark matter exists in large halos which envelope galaxies. The dark matter halos can have an arbitrary shape, in fact many people have made “maps” of the dark matter by looking at gravitational lenses. The size of the halo can be a few to many tens of times larger than the galaxy which resides in side of the halo. Many very large halos can host several galaxies (though rarely more than a few galaxies per halo).

The mistake George makes is when he says that it’s “near the Galactic center”. This is very false. The galactic center is *inside* a dark matter halo. In fact, the center of the halo and the galaxy need not be the same, such as in the case of this galaxy cluster:

http://en.wikipedia.org/wiki/Bullet_Cluster

Also, since the dark halos host galaxies, and earth is in a galaxy, then earth is in a dark halo. Therefore, dark matter *EXISTS* all around us, even here on Earth. There are several major experiments set up to detect dark matter and measure it’s properties. You can learn about a famous experiment at:

http://en.wikipedia.org/wiki/Cryogenic_Dark_Matter_Search

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