Xiurui Zhao

One night, a star at the edge of the sky suddenly flickered and brightened for a few days. It wasn't a supernova, and no cloud passed by — an invisible planet drifted between the star and Earth. Its gravity bent the light of the distant star like a pair of glasses focusing a sunbeam.

One night in 2008, something in the core of the distant galaxy J1047+5907 flared sharply in X-rays. That's how the neighborhood of a supermassive black hole sometimes behaves: a scorching cloud of gas above it suddenly blasts out a powerful stream of light. The black hole itself emits nothing, but its surroundings can light up like a neon sign.