The first results from the Alpha Magnetic Spectrometer aboard the International Space Station were discussed during a Press Briefing at NASA Headquarters. Those results confirm an unexplained excess of high-energy positrons in Earth-bound cosmic rays. Antimatter is rare in the universe today. Because Earth receives a limited amount of energetic antimatter, antiparticles serve as unique messengers of high-energy phenomena in the cosmos, or signatures of exotic new physics.
“In particle physics, antimatter is material composed of antiparticles, which have the same mass as particles of ordinary matter but have opposite charge and quantum spin. Antiparticles bind with each other to form antimatter in the same way that normal particles bind to form normal matter. For example, a positron (the antiparticle of the electron, with symbol e+) and an antiproton (symbol p) can form an antihydrogen atom. Furthermore, mixing matter and antimatter can lead to the annihilation of both, in the same way that mixing antiparticles and particles does, thus giving rise to high-energy photons (gamma rays) or other particle–antiparticle pairs. The end result of antimatter meeting matter is a release of energy proportional to the mass as the mass-energy equivalence equation, E=mc2 shows.
There is considerable speculation as to why the observable universe is apparently composed almost entirely of matter (as opposed to a mixture of matter and antimatter), whether there exist other places that are almost entirely composed of antimatter instead, and what sorts of technology might be possible if antimatter could be harnessed. At this time, the apparent asymmetry of matter and antimatter in the visible universe is one of the greatest unsolved problems in physics. The process by which this asymmetry between particles and antiparticles developed is called baryogenesis.” – Wikipedia
“Scientists say a $2 billion antimatter-hunting experiment on the International Space Station has detected its first hints of dark matter, the mysterious stuff that makes up almost a quarter of the universe.
The evidence from the Alpha Magnetic Spectrometer, revealed Wednesday at Europe’s CERN particle physics lab, is based on an excess in the cosmic production of anti-electrons, also known as positrons. The AMS research team can’t yet rule out other explanations for the excess, but the fresh findings provide the best clues yet as to the nature of dark matter.
“Over the coming months, AMS will be able to tell us conclusively whether these positrons are a signal for dark matter, or whether they have some other origin,” Samuel Ting, an astrophysicist at the Massachusetts Institute of Technology who leads the international AMS collaboration, said in a CERN news release.” – Cosmiclog NBC News
“Modern theories of particle physics and of the evolution of the universe suggest, or even require, that antimatter and matter were equally common in the earliest stages¿so why is antimatter so uncommon today? The observed imbalance between matter and antimatter is a puzzle yet to be explained. Without it, the universe today would certainly be a much less interesting place, because there would be essentially no matter left around; annihilations would have converted everything into electromagnetic radiation by now. So clearly this imbalance is a key property of the world we know. Attempts to explain it are an active area of research today.” – Scientific American
“Positrons were reported in November 2008 to have been generated by Lawrence Livermore National Laboratory in larger numbers than by any previous synthetic process. A laser drove electrons through a millimeter-radius gold target’s nuclei, which caused the incoming electrons to emit energy quanta that decayed into both matter and antimatter. Positrons were detected at a higher rate and in greater density than ever previously detected in a laboratory. Previous experiments made smaller quantities of positrons using lasers and paper-thin targets; however, new simulations showed that short, ultra-intense lasers and millimeter-thick gold are a far more effective source.” – Wikipedia