[PatrickHenry]

Footnotes are in the originial article.

A related thread was posted a few months ago, but Nature just published this article, so presumably it's newsworthy:
Astronomers claim dark matter breakthrough.

[PatrickHenry]

PING. [This ping list is for the evolution side of evolution threads, and sometimes for other science topics. FReepmail me to be added or dropped.]

[Servant of the 9]

So, a substantial portion of the universe is made up of WIMPS.
That sorta explains Democrats now doesn't it?

So9

[Physicist]

Boehm's team says that if dark matter were made up of particles with a low mass, these particles could generate positrons and electrons when colliding with antimatter. When these products collide, they generate gamma rays.

I'll make the same comment that I made back when someone claimed that a 100 MeV dark matter particle was responsible for the 511 keV emissions. If these things are so light, and can annihilate and produce electron-positron pairs, why don't we see them produced in electron-positron colliders? Whether it's a 100 MeV particle (as was claimed before) or a 1 MeV particle (as is claimed here), we should see GOBS of them produced by every e+e- collider, but we just don't.

Either the dark matter particles are extremely heavy, or they don't couple to electrons. I don't see any way around that.

[Blood of Tyrants]

So now dark is light, good is bad, black is white, up is down. Bizarro world, I tell ya'.

[Monty22]

I never believed in 'massless' stuff. Always thought neutrinos had some mass, no matter how tiny. I figure photons do too.

[JimRed]

They are called weakly interacting massive particles, or WIMPs.

For a moment I thought I had entered a time warp and this was being posted on April first...

[Lonesome in Massachussets]

Dark Matter Could be Light

Sure, the speed of light is 299,792,458 meters per second, but what's the speed of dark?

[Captain Beyond]

Bump

[Bloody Sam Roberts]

dark matter particles need not be massive at all. Instead, they think they could be between ten and a thousand times lighter than a hydrogen atom.

Woof. Tha's a whollotta particles.

[edsheppa]

Intriguingly, dark matter is known to be concentrated in our galaxy's central bulge, thanks to observations of how the missing mass affects the orbit of stars.

I don't think that is right which makes the whole article suspect. One of the evidences for dark matter is that the velocity of stars as a function of distance from the center of their galaxy is too flat. If a galaxy's gravitating matter were concentrated in its center, velocity would fall off proportionally to inverse of the square root of the distance but it decreases much less rapidly. Put the dark matter in a halo around the galaxy and it will account for the discrepancy.

[Benrand]

Gamma rays?

Did Bruce Banner find this discovery?

[Consort]

The rays support an exotic theory about dark matter: that it consists of very light particles.

Doesn't everything start out that way?

[Liberty Valance]

Bush's fault