18 Years Later: A Supernova Lights Up the Radio ⚡ экспресс
For the first time, radio emission has been detected from Type II supernova (explosion of a massive star) SN 2007it, 18 years after the outburst. The discovery was made as part of a program searching for the 'rekindling' of old supernovae, where the stellar remnant collides with dense circumstellar material. The signal was detected at frequencies of 5.5 and 9.0 GHz, but not at a lower one; this hints at either rapid brightening or internal absorption. Just as a roaring engine can drown out music, dense material around the star can hide radio waves.
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.