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View Full Version : Are there ANTIMATTER stars out there???



Dean Whitehead
2010-Dec-06, 06:26 AM
I bought a book 2 weeks ago (Michio Kaku, Physics of the Impossible) i was reading a chapter about antimatter and got me thicking if there are antimatter stars. We could study them they would solve alot of problems energy wise. if we had the technology we could create ower own tiny antimatter star compressing anti-hydrogen till fusion takes place but this is a few 100 meby 1000s of year away but we would have almost infinity energy for many year because we all know the small the star the longer it lives.

I think its strange that we havn't found any yet?

Any idears??

antoniseb
2010-Dec-06, 12:32 PM
So far, the evidence is that antimatter does not exist in nearly the quantity required to make stars.
Also, just as a practical issue, while we've demonstrated that we can make anti-Hydrogen (at huge energy expense), collecting it into a big enough pool to make a fusing antimatter star would not give any more energy than collecting the cheaply available Hydrogen to make a fusing matter star.

caveman1917
2010-Dec-07, 02:56 AM
If we assume there is a non-zero (no matter how small) chance that in any section of space the right 'ingredients' happen to have come together to make an anti-matter star (a local dominance of anti-matter over matter), and we assume an infinite universe, there is bound to be at least one somewhere around. In fact, an unlimited number of them in that case.
But the odds are arguing against even one in our observable universe, nevermind actually detecting and identifying it.

Cougar
2010-Dec-09, 08:17 PM
Are there ANTIMATTER stars out there???

No, not that we can see. Matter and antimatter generally are generated together, in equal amounts. In the early universe, apparently, somehow, there were 1,000,000,001 matter particles for every 1,000,000,000 antimatter particles. Of course, when they come together, they annihilate and release a photon. That's why we now see about a billion photons for every matter particle throughout the universe. The primordial antimatter is all gone.

StupendousMan
2010-Dec-09, 08:44 PM
Just to play devil's advocate for a moment: imagine that some distant star or galaxy is entirely
made of antimatter (easy to imagine) and _completely_ isolated from interstellar or intergalactic
matter of the ordinary kind (not so easy to imagine).

We look at this star or this galaxy with instruments here on Earth. How can we tell that
it is made of antimatter instead of regular matter?

Please be specific.

darkwood
2010-Dec-09, 10:38 PM
Well i can only assume it must have a unique signiture on the light spectrum if it was detectable as any positive or negative particle would be wiped out of existance as it passed into matter region as we know, maybe the light spectrums would e inverse in their patterns but just a thought.

Grey
2010-Dec-10, 04:01 PM
Just to play devil's advocate for a moment: imagine that some distant star or galaxy is entirely
made of antimatter (easy to imagine) and _completely_ isolated from interstellar or intergalactic
matter of the ordinary kind (not so easy to imagine).

We look at this star or this galaxy with instruments here on Earth. How can we tell that
it is made of antimatter instead of regular matter?

Please be specific.We can't. As far as we can tell, antimatter stars and galaxies would behave just like ones made out of matter (well, apart from a few small differences in the way the weak force behaves, but I don't think that would be enough to make an observable difference). However, that second condition is, as you note, not very realistic. At the boundary between a matter and antimatter region, we'd have steady annihilation of the two, producing continuous high energy gamma radiation. That gamma radiation would also have a particular signature, since there would be strong peaks in the emission spectrum at the annihilation energies of protons, neutrons, and electrons. Since we don't see that anywhere, we can be reasonably certain that there aren't any large accumulations of antimatter anywhere.