Tao An

The globular cluster M22 is a dense swarm of hundreds of thousands of stars, hanging in our galaxy like a glowing beehive. In such a crowded environment, stars often collide and swap partners, but massive objects like black holes were thought to be quickly ejected by gravitational interactions.

For six straight years, the radio telescope at Effelsberg recorded the "breathing" of the distant blazar 1156+295 — a galaxy whose core shoots out a jet of plasma at nearly the speed of light. Every few months, its radio waves flared up and then faded.

In a distant galaxy, at a distance that light takes 11 billion years to cross, something flashed. The Einstein Probe X-ray telescope caught a brief, needle-prick-like burst: it lasted only a few dozen seconds.

A massive star ends its life in a spectacular collapse: the core compresses into a neutron star or a black hole, while the outer layers fly off in a dazzling supernova.