The first light of a supernova: catching a shock breakout in X-rays
On 21 March 2026, an X-ray telescope in orbit registered a faint flash from a galaxy about 500 million light-years away. It lasted roughly seven minutes and then faded. That flash was the first light of a supernova — not the slow brightening you normally see over weeks, but the instant the explosion’s shock wave punched through the surface of the star. Astronomers call it a shock breakout, and this is only the second time in about two decades one has been caught cleanly in X-rays. ...