Artist concept art of an antimatter propulsion system. Matter – antimatter annihilation offers the highest possible physical energy density of any known reaction substance. Credit: NASA.
Click to enlarge video or view it below.

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.