Cosmic Antimatter Excess Confirmed

sciencehabit writes "In 2008, the Italian satellite PAMELA picked up an unusual signal: a spike in antimatter particles whizzing through space. The discovery, controversial at the time, hinted that physicists might be coming close to detecting dark matter, an enigmatic substance thought to account for 85% of the matter in the universe. Now, new data from NASA's Fermi Gamma-ray Space Telescope confirm the spike (abstract)."

Comments

Dark matter or antimatter?

[Anonymous Coward]

I'm confused, is this about antimatter or dark matter?

Re:Dark matter or antimatter?

[geekoid]

(not that that will stop me from commenting..)

and that is what's wrong with the world.

I don't know jack abut the subject, but I'll be damned if that stopped me from commenting like I'm an expert.

Anti-matter vs. dark matter

[walter_f]

In my opinion and in contrary to what the original posting suggests, anti-matter should not be viewed as particularly "dark".

E.g., anti-Hydrogen, consisting of an anti-proton and a positron, will readily absorb a quantum of energy (a photon, which happens to be one of the particles that are their own anti-particles) and re-emit a photon again, just like "plain old" hydrogen. Thus, a cloud of anti-hydrogen should be observable as easily (or difficultly) as a cloud of hydrogen, assuming their masses, their viewing distances and all other parameters like temperature, density etc. being equal.

So there should be no difference in observability here, due to the fact that photons are citizens of both realms, of "nornal" matter as well as of anti-matter, and will interact with mass particles of both realms in the same way.

Obviously, "dark matter" looks like a very different beast...

Re:Anti-matter vs. dark matter

[Anonymous Coward]

Interestingly enough, we could all be made up of antimatter. If after the Big Bang, the amount of anitmatter was greater than matter, we be made (assuming me happened to exist) out of anitmatter, but call the anitmatter "normal matter", and call the real matter "anitmatter".

That's gibberish. You might as well says that cats might really be called dogs. They're not. Which is matter and which is anti-matter (or any other labels) depends on what names people have given them. There isn't a "right" answer outside of what people have come up with.

Re:Why are we discussing this?

[Tukz]

woooosh