How Does Dark Matter Influence Gravity in Galaxies?

keepitmoving · Jun 28, 2012

I've heard that most of dark matter is located in the outer portions of galaxies. If that is so, wouldn't the gravity from the dark matter tend to pull the galaxies apart?

Chronos · Jun 28, 2012

The center of mass is still within the galaxy.

keepitmoving · Jun 28, 2012

many thanks Chronos

Chalnoth · Jun 29, 2012

keepitmoving said:

I've heard that most of dark matter is located in the outer portions of galaxies. If that is so, wouldn't the gravity from the dark matter tend to pull the galaxies apart?

Even if the dark matter wasn't more dense towards the center of the galaxy, the net gravitational force on the inside of a shell of matter is identically zero.

How Does Dark Matter Influence Gravity in Galaxies?

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