Wenwen Zuo

X-rays from the vicinity of a black hole don't arrive all at once. Some of them first fall onto a disk of scorching gas, get reflected, and only then travel to the telescope. This delay is like an echo in the mountains: first you hear the direct sound, then the response from the cliff.

At the centers of many galaxies lurk supermassive black holes. From time to time they 'scream' — unleashing powerful X-ray flares. Scientists have long puzzled over the nature of these 'quasi-periodic eruptions'.

The night sky is full of rings and bubbles, but in the radio band they look different. In data from the Australian radio telescope ASKAP, a structure has surfaced that resembles two soap bubbles blown from the same straw.