18 Years Later: A Supernova Lights Up the Radio ⚡ экспресс
Astronomers have for the first time picked up a radio signal from supernova SN 2007it, which exploded over 18 years ago in a distant galaxy. It's like a smoldering campfire that suddenly blazes up again: likely, the star's remnants are colliding with surrounding material. What other mysteries does this 'living' supernova hold?
A supernova explosion is the death of a massive star, leaving behind a gas cloud. If there's plenty of hydrogen around, the shock wave spreads like an echo from a distant gunshot. For supernova SN 2007it, that echo arrived 18 years later: the wave finally slammed into a dense clump of material ejected by the star before the explosion, triggering radio emission. The ATCA telescope caught the radio signal. Brightness measurements showed the emission is rapidly brightening.
The discovery explains how stars shed mass before the final blast, scattering raw materials for new worlds across the cosmos. This is the first time a supernova has given a radio echo with such a delay.
🎯 The signal was so unexpected that it was almost dismissed as radio interference, and only a data check confirmed it: a supernova, finally speaking up after 18 years.