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Re: Re: Re: Darkmatters

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Posted by Alexander on February 27, 2001 02:15:54 UTC

No, it is believed to spread more or less uniformly at least throughout galaxies and well beyond as the rotational velocity curve suggests (moreover, it suggests that the dark matter is not concentrated in the galactic plane but is rather uniformly spread in a spherical haloes in and around galaxies).

Density of ordinary matter in Earth-Moon neigborhood is very high (Earth+Moon themselves). If you calculate this density in Earth-Moon volume sphere, you'll get something like 24 g/m^3. This is way higher than average density of Universe which is about 6x10^-24 g/m^3 (thus, way higher than of dark matter too, which makes up most of this density). So we may safely say that the presence of dark matter in our neighborhood is way less that the presence of protons/ neutrons/ electrons. And that the gravity here dominates exclusively by Earth/Moon/Sun gravity.

Also, density of hydrogen in interplanetary Solar system volume away from planets is still way higher than of dark matter.

Looking at Moon you look through about 2x10-15 g/m^2 of dark matter, at Sun - via about 7x10^-13 g/m^2, at nearest stars - via about 10^-8 g/m^2, looking 1 billion light years away you see via about 2 g/m^2 of dark matter.

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