G. Miniutti

At the core of the distant galaxy SDSS J1335+0728, 2.5 billion light-years from Earth, a supermassive black hole beats out a rhythm. Every few days it flares in X-rays like a cosmic metronome, but in 2025 that metronome suddenly shifted from allegro to andante.

At the heart of every galaxy slumbers a supermassive black hole. When it devours matter, its surroundings flare up: this is an active nucleus. How can we learn about past outbursts if the black hole is silent? The answer lies in light echoes.

At the center of galaxy NGC 1068, located 47 million light-years away, lies a black hole hidden behind a dense veil of dust. But X-rays emitted by iron pierce through that veil. The Japanese satellite XRISM captured this glow and split it into colors, much as a prism splits sunlight.