[Aki]

I find it hard to believe that dark matter does not radiate. Everything radiates, including icwe caps in the north pole. It is believed that dark matter is made up of WIMPs, and since it is a particle, it should radiate. Well I was thinking maybe dark matter does radiate waves, but the range is outside of the electromagnetic spectrum we know and it is beyond detection with the equipement we have. Is that possible?

[Tormod]

Aki,

Do all particles radiate? I thought radiation in the electromagnetic spectrum at least *is* particles...

[pgrmdave]

Is it possible that they radiate in an entirely different spectrum, one that we haven't discovered because our area of the universe doesn't have much of it?

[lindagarrette]

If dark matter radiated, we would be able to find it. So I say no, it does not.

[GAHD]

I suppose if it was a different state of matter it could radiate beyond known wavelengths....

Still it could be anything. Heck it could even be forces of another dimension acting on our 'brane.

Who knows?

[maddog]

Well, I'm baack! Skiing in Steamboat was wonderfull!

Aki -- The theory of Dark Matter being WIMPs is out because theory of WIMPs is out of
---> favor... Best way to check is do a google search with both criteria and "dark matter"
---> in quotes.

Tormod -- Yes, Radiation in the context discussed here are EM (both wave or particle
---> description).

All -- Dark Matter as defined as dark because no evidence for radiation has yet been
---> found. Such a concept was found by gravitational lensing of a distant object when
---> nothing was found closer in the field of view. There are now numerous cases. A
---> recent sky survey has shown matter to be composed of 5% matter (we do see),
---> 25-30% of Dark Matter (we don't see), and 65-70% of Dark Energy (haven't figured
---> out how this percentage is verified). There are 3 flavors of Nuetrinos that all are
---> weakly interacting with other particles including photons. There are still a bunch of
---> particles yet to find as the superpartners of the normal particles, if you go by
---> Supersymmetry.

Maddog

[GAHD]

ugh, I still wonder if dark matter couldn't be two-dimentional, now there'd be a twist.

[BlameTheEx]

Perhaps dark matter does not radiate, or radiates very little. Why should it radiate? Consider the possible reasons:

1) Radiating heat left over from the big bang. - Unless it almost a perfect insulator or in very large chunks (say star sized) the heat should have all dissipated.

2) Re-radiating energy absorbed from starlight, cosmic background radiation, and the like. - Not an option if dark matter is a poor absorber. If it is not made with charged components (i.e. orbiting electrons) it won't be. Think of a perfect glass. If it is in largish chunks (say asteroid to planet sized) of ordinary matter there won't be enough surface area to count.

3) Decay. - But dark matter may be stable.

[Tormod]

Originally Posted by maddog

Well, I'm baack! Skiing in Steamboat was wonderfull!

Good to see you back! Too bad you lost our chat yesterday...make sure you make it to the next one. Skiing is a bad, bad excuse.

Tormod -- Yes, Radiation in the context discussed here are EM (both wave or particle
---> description).

Okay, I stand corrected.

[Tormod]

Wait - Maddog - hang on. I thought particles are wavelike in nature except when interacting with other particles. So radiation = particles, no?