In 2008, the European satellite PAMELA detected a surprisingly large concentration of high energy positrons above our atmosphere. The presence of so many positrons, the anti-matter counterpart of electrons, goes against theoretical predictions but has been verified by other detectors. In new research published earlier this month by the AAAS journal Science , a team of researchers from Germany, Mexico, Poland, and the United States now cast doubt on one of the leading explanations for the mysterious excess—leaving its origin still unknown.
brought to you by the American Physical Society