Why does the amount of dark matter increase the further away from the

[sytric]

Why isn't the dark matter just randomly distributed? How does it know where to go? Why does the amount of dark matter increase the further away from the galaxy's center?

 

[Chronos]

Dark matter yo-yo's in and out of the local center of gravity. It gains velocity as it approaches the center of gravity and slows as it exits. Because of its low velocity in the 'halo' region, it tends to spend more time there.

 

[vociferous]

Why isn't the dark matter just randomly distributed? How does it know where to go? Why does the amount of dark matter increase the further away from the galaxy's center?

You might ask the same questions about visible matter in Galaxies. It is not evenly distributed either, especially not in spiral galaxies.

The distribution of mass is likely a result how how different galaxies formed.

We do not believe dark matter would be changed by most normal astrophysical reactions other than gravity (friction, for instance), so where it tends to settle would be different than where normal baryonic matter would settle.

 

[phinds]

We do not believe dark matter would be changed by most normal astrophysical reactions other than gravity (friction, for instance), so where it tends to settle would be different than where normal baryonic matter would settle.

Yes, but the point is more that it probably DOESN'T "settle". As Chronos pointed out, it yo-yos from one side of the galaxy to the other

 

[zyxwv99]

I have the same issue with long-period comets. It's almost as if they're avoiding us.

 

[phinds]

I have the same issue with long-period comets. It's almost as if they're avoiding us.

You think it was something we said?

 

[vociferous]

Yes, but the point is more that it probably DOESN'T "settle". As Chronos pointed out, it yo-yos from one side of the galaxy to the other

I do not think anything really "settles", but without a way to measure the peculiar velocity of dark matter (as far as I know), I think the best we have are computer models.