Artist's impression of the aftermath of a merger between two supermassive black holes during a galaxy collision.
Combining the observing power of two future ESA missions, Athena and LISA, would allow us to study these cosmic clashes and their mysterious aftermath for the first time.
We could see the emergence of a new X-ray source, and perhaps witness the birth of an active galactic nucleus, with jets of high-energy particles being launched at close to the speed of light above and beyond the newly formed black hole.
More information: A unique experiment to explore black holes
On Earth, we deal with gravity every day. We feel it, we fight it, and – more importantly – we investigate it. Space agencies such as ESA routinely launch spacecraft against our planet’s gravity, and sometimes these spacecraft borrow the gravity of Earth or other planets to reach interesting places in the Solar System. We study the gravity field of Earth from orbit, and fly experiments on parabolic flights, sounding rockets and the International Space Station to examine a variety of systems under different gravitational conditions. On the grandest scales, our space science missions explore how gravity affects planets, stars and galaxies across the cosmos and probe how matter behaves in the strong gravitational field created by some of the Universe’s most extreme objects like black holes. Join the conversation online this week following the hashtag #GravityRules