There’s nothing like a merger to stir things up. That applies not only to companies and families, but to galaxies as well. One example is Messier 61. A recent merger with a smaller galaxy has brought its central black hole to life, triggered the birth of thousands of new stars. It also kicked out a ribbon of stars that’s as long as the galaxy itself.

Messier 61 is a lot like our home galaxy, the Milky Way. It’s about the same size and mass, and it looks about the same – a beautiful spiral with a long bar of stars across its middle.

But a close look shows big differences. M61 is giving birth to stars at a much faster rate than the Milky Way. It’s produced more supernovas – the explosive deaths of young, massive stars. The supermassive black hole in its heart is “feeding” much more voraciously. And last year, astronomers discovered a “streamer” of stars behind M61. The streamer is a hundred thousand light-years long, and ten thousand wide.

The likely cause of all that activity is a merger with a smaller galaxy. The encounter squeezed big clouds of gas, triggering the starbirth. It provided fresh material for the black hole. And it pulled out stars in the galaxies to form the long tail – stirring things up in a beautiful spiral galaxy.

Script by Damond Benningfield