Free Astronomy Magazine July-August 2025

37 JULY-AUGUST 2025 ASTRO PUBLISHING T his image, taken with the Atacama Large Millimeter/submillimeter Array (ALMA), shows the molecular gas content of two galaxies involved in a cosmic collision. The one on the right hosts a quasar –– a supermassive black hole that is accret- ing material from its sur- roundings and releasing intense radiation directly into the other galaxy. [ALMA (ESO/NAOJ/ NRAO)/S. Balashev and P. Noterdaeme et al.] T his artist’s impression shows a ‘cosmic joust’ –– a galactic merger in which the galaxy on the right hosts a quasar at its core. This quasar is powered by a supermassive black hole swallowing up material around it and emitting a powerful cone of radiation, piercing the other galaxy like a lance. As this radiation interacts with the galaxy on the left, it disrupts the clouds of gas and dust within, leaving behind only the smallest and densest regions. These regions are likely rendered inca- pable of star formation after the process. [ESO/M. Kornmesser]