When two galaxies collide, the compressed gas between them can force hydroxyl molecules to emit intense, coherent radio waves: a cosmic maser. The MeerKAT radio telescope in South Africa—an array of 64 linked receptors spread across an 8-kilometer baseline—has now detected one of extraordinary power from 8 billion light-years away, strong enough to be classified as a “gigamaser.”
A maser is the microwave equivalent of a laser: radiation of a single wavelength, amplified and coherent. In this case, the signal originates from molecules in gas compressed by the galactic collision, which stimulates them to emit intense radio waves in lockstep. The signal was then further amplified by an unrelated galaxy sitting between the source and Earth, whose mass curves spacetime and acts as a natural lens—a fortunate alignment that made the discovery possible, The Independent of Uganda reports. The South African Radio Astronomy Observatory reports that the signal is “so luminous it warrants classification as a gigamaser, a rare cosmic phenomenon.”
