The Clumping of Dark Matter: A Question of Friction?

[skippy1729]

Dark Matter interacts only gravitationally. Stars and planets form by gravitational clumping. Clumping of whatever is there: gas and dust and presumably dark matter. By the cosmological principal we are at a typical generic location within the universe. Whenever the sun and Earth clumped into existence we would typically expect some Dark Matter to be in the vicinity. Since the Dark Matter on Earth could not, by definition, form chemical bonds with baryonic matter or with itself it must have slipped through the cracks and gravitationally clumped at the center of the earth.

Is this a reasonable deduction or am I missing something?

Skippy

 

[Ich]

What falls down will rise again, unless there is something to stop it. What would stop DM from simply falling through Earth and coming out on the other side, if it's not interacting?

 

[skippy1729]

What falls down will rise again, unless there is something to stop it. What would stop DM from simply falling through Earth and coming out on the other side, if it's not interacting?

It is interacting gravitationally. As soon as it passes through the center it will start falling back and eventually clump at the center.

 

[PhanthomJay]

Since the Dark Matter on Earth could not, by definition, form chemical bonds with baryonic matter or with itself it must have slipped through the cracks and gravitationally clumped at the center of the earth.

It is all speculation at this point, but the 'crack' that 'dark matter' may have slipped through, might very well be through the miniscule dimensions of the higher order spatial dimensions, and not in the form of matter, but rather, though gravitational energy from a parallel universe. While WIMPS and MACHOS seem to be getting the most attention these days in an attempt to explain dark matter, the theory proposed by the Brane Theorists, and briefly alluded to by Hawking in his last book, focuses on ther fact that unlike electromagnetic waves, short gravity waves might be able to penetrate between universes, their matter, which causes the waves, forever hidden, but felt in this universe from the gravitational effects. So what we call dark matter may be gravitational energy from another universe. If I were a betting man, my money's on that one.

 

[Chalnoth]

It is interacting gravitationally. As soon as it passes through the center it will start falling back and eventually clump at the center.

Nope, needs friction to do this. Dark matter experiences almost no friction, so it just heads right back out of any gravitational potential well it enters. Granted, it can't keep doing this indefinitely, as it does experience some friction, even if that friction is only due to gravitational interactions. However, the time scale for the collapse of dark matter is vastly longer than the time scale for collapse of normal matter, such that dark matter forms very large, diffuse "haloes", typically with galaxies of normal matter situated at their centers.