Re: Could Dark Matter be here on earth?

Marvin the Martian wrote:
On Wed, 27 May 2009 12:59:55 -0400, Greg Neill wrote:

Marvin the Martian wrote:
On Wed, 27 May 2009 09:15:59 -0700, YKhan wrote:

On May 26, 12:04 pm, Marvin the Martian <mar...@xxxxxxxxxxxx> wrote:
If the particle is free, that is correct. However, matter falling
down a gravitational well will exert tidal forces on an object like
the earth, which would dissipate some of that energy as heat.

First, Dark Matter is all free particles.

Particles of what? It's not neutrinos, we know how many neutrinos are
passing through the earth. There is no other known massive particle
that it could be.

Particles of dark matter, whatever that happens to be. And that's the
point of calling it Dark Matter -- it's not matter from the known tool
box.

May as well claim gremlins are pushing the galaxies. By definition, you
can't find dark matter, its only effect is to fix an existing theory that
fails to predict.

Unless it is found. Do you advocate not looking for it? If so, why?


Second, tidal forces that are
resisted is entirely due to an interaction between gravity and
electromagnetic forces. The heat given off is photons from the
electromagnetic force.

And when this dark matter interacts with real matter, both of them
undergo a force. The real matter would radiates some of the energy of
the interaction away, and the dark matter would lose energy.

Or it gains energy (slingshot, or gravity assist trajectory).

In a purely elastic collision, it would gain or lose energy with equal
probability. In an even slightly inelastic collision, it would tend to
lose energy more often than gain.

The important point is, how much and over what time period? The
gravitational coupling constant is very small, and any given particle
with greater than escape velocity will generally get only one pass
at a given target.


I keep repeating this, and you keep ignoring it. How many more times
would you like to clip out where I point out that there is a loss of
energy and keep repeating this presumption that all dark matter
interactions are with dark matter?

And we're pretending there are no gravity waves. What's up with that?

You have yet to characterize the magnitude of the possible energy loss
(or gain) due to gravitational interaction of DM and Normal Matter. You
continue to ignore the fact that gravitational waves from even
*enormous* mass systems are puny and at the ragged limit of
detectability. A DM particle passing through a neutron star would
hardly even notice it.

The loss of energy would be small. Now, repeat that for 14 billion years
and for most of the mass of the universe, and it begins to add up.

You still haven't made any order of magnitude estimates. How many
encounters of the right type with a concentration of normal matter do
you think will happen to a given DM particle over time?


Further, if this thing had 1/2 spin, they would have found some of them
in neutrino detectors. They didn't. So, we're talking 0 spin here; some
*** little boson particle in a universe of fundamental fermion
particles. What's more, since these particles have been expanding since
the big bang, without interactions, they should be cold; that is, they
would separate out by relative velocity. So, now you have a bunch of
cold bosons that DON'T form BECs.

The dark matter idea is weak, bordering on non-science. I'm not sure
why some people here think that it is now physics gospel, when it
isn't, and that it must not be questioned and that anyone who questions
it is fair game for their anti-social behavior.

I think you want to think that people treat DM as gospel just so you'll
have something to rail against.

Childish flame noted.

< mixed bandwagon/appeal to authority fallacy snipped >

Didn't like to see your bias and untenable position pointed out, eh?


I don't go with the bandwagon fallacy, and never did. Nor am I big on
appeals to authority fallacies.

So, where you come from, a good "burn" is a suitable replacement for a
theory. k

I 'm afraid I cannot understand what you're saying here. You seem to be
trying to construct a straw man argument of some sort, but I can't make
it out.


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