850 light-years away, the (now) blue supergiant Rigel, in the constellation of Orion, explodes in a spectacular type II supernova, lighting up Earth’s night sky like 100 full moons concentrated in one spot. Before Rigel, Orion’s other very bright star, Betelgeuse (620 light-years away), may have already exploded in a type II supernova, but given its current instability, it’s difficult to determine how long it will take (thousands or millions of years).
