How Does Dark Matter Influence Gravity in Galaxies?

AI Thread Summary
Dark matter is primarily found in the outer regions of galaxies, raising questions about its gravitational effects. Some argue that this distribution could lead to galaxies being pulled apart due to the gravitational influence of dark matter. However, it is noted that the net gravitational force within a shell of matter remains zero, regardless of dark matter density. This suggests that dark matter's presence does not necessarily destabilize galaxies. Understanding the role of dark matter in galaxy dynamics remains a complex topic in astrophysics.
keepitmoving
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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?
 
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The center of mass is still within the galaxy.
 
many thanks Chronos
 
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.
 

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