If its dark matter that keeps stars in galaxies from being flung out, what keeps the dark matter from the same fate ? Yet more dark matter.....?
2007-03-21 11:05:11 · 3 answers · asked by black sheep 2 in Science & Mathematics ➔ Astronomy & Space
I think you're confused. Dark matter makes up about 70% of the matter in galaxies, which contributes to the structure and rotation speeds and masses of the galaxies. Which is I guess what you mean - the further-out arms of the galaxies are still kept in place by the dark matter contributions to the overall mass of the galaxy. But that's what keeps it in place - the overall mass. You don't need to add more mass on top of that to keep it the same.
2007-03-21 11:10:08 · answer #1 · answered by eri 7 · 2⤊ 0⤋
Gravity.
Dark matter does not keep stars in galaxies; it is the gravitational interaction between the matter that exists in the galaxy that keeps both stars and dark matter.
All matter exerts gravitational force; even your body does although it is very small compared to the Earth's gravity.
2007-03-25 09:43:17 · answer #2 · answered by Tenebra98 3 · 0⤊ 0⤋
Dark matter increases the overall mass of the universe. Scientists don't even know what dark matter is, just that they gave it a name.
There is also Dark Energy that has the opposite effect. We also don't know what that is.
Dark Energy and Dark matter make up 87% of the universe.
2007-03-21 11:09:13 · answer #3 · answered by Anonymous · 0⤊ 0⤋