The universe's most powerful telescope

SN 2025mkn is a Type II supernova and it wasn't supposed to be visible at all. The violent death of a massive star that had exhausted its nuclear fuel and collapsed under its own gravity sits at a redshift of 1.371. That places it roughly 9 billion light years away. At that distance, an ordinary stellar explosion simply doesn't produce enough light to study in any useful detail. Yet astronomers can see this one with extraordinary clarity and we have gravity to thank.