MINNEAPOLIS — Bubbles of radiation billowing from the galactic center may have started as a stream of electrons and their antimatter counterparts, positrons, new observations suggest. An excess of positrons zipping past Earth suggests that the bubbles are the result of a burp from our galaxy’s supermassive black hole after a meal millions of years ago.
For over a decade, scientists have known about bubbles of gas, or Fermi bubbles, extending above and below the Milky Way’s center (SN: 11/9/10). Other observations have since spotted the bubbles in microwave radiation and X-rays (SN: 12/9/20). But astronomers still aren’t quite sure how they formed.
