Cosmic rays are incredibly fast particles, since they're being shot down from space at high energies. Positrons make up a small percent of these super speedy particles, but nobody is entirely sure where or how they're made.
To make matters more confusing, in 2008 a probe in Earth's orbit called PAMELAdetected more high energy positrons reaching our corner of the cosmos than we'd expect .... http://www.sciencealert.com
