14 DAY TRIAL // Astronomers believe that countless invisible galaxies may be orbiting the Milky Way. These so-called dark galaxies were first hinted at in 2005, when a team of investigators found the first telltale signs of their existence.
At the time, the researchers were studying the Virgo Cluster. They found a large hydrogen cloud that was producing no starlight, but which was also in the process of colliding with our galaxy. The formation is located about 50 million light-years from Earth.
Neutral hydrogen gas within the invisible galaxy gives off a specific radio signature, which the scientists were able to detect. Current estimates indicate that the cloud, called VirgoHI 21, could literally seed a new galaxy, since it's capable of producing up to 100 million stars.
It is now believed that many such invisible galaxies – areas containing a lot of mass, but no stars – exist around the Milky Way. A dedicated survey could help astronomers create a map of these objects, Daily Galaxy reports.