“Megamaser” sounds like something an alien warship might use to destroy planets. The reality is a little less dramatic, but it’s no less interesting. A megamaser is a beam of energy from another galaxy. And astronomers use these beams to study galaxies — especially the supermassive black holes at their hearts.

A megamaser fires up when a bright energy source lights up a cloud of gas and dust. The energy “pumps up” certain molecules in the cloud — water is one of the most common — amplifying the amount of energy they produce. The result is a tightly focused beam of microwaves. The beam can be anywhere from 10 to a million times as bright as the Sun.

Some megamasers are produced by galaxies that are merging with other galaxies. Such galaxies are giving birth to many new stars, which provide some of the energy to power the masers.

Many water masers are found in galaxies with active black holes in their hearts. Those masers are powered by giant disks of super-heated gas and dust around the black holes. Astronomers use the masers to measure the mass of the black hole, study the disk around the black hole, and more.

And in one recent study, they probed a galaxy that’s almost 13 billion light-years away. That means we see the galaxy as it looked when the universe was less than a billion years old. The study provided the most detailed look at the conditions in gas clouds in the early universe to date — thanks to the power of a megamaser.
 

Script by Damond Benningfield