London – Nine “dwarf galaxies” a million times smaller than normal galaxies have been identified in orbit around the Milky Way.
The mini-galaxies are a billion times dimmer than the Milky Way and were only found with the help of the most powerful digital camera in the world, which can see the faint glow of normal-sized galaxies as far away as 8 billion light years from Earth.
It is the biggest collection of dwarf galaxies observed at any one time, and the first to be seen in 10 years. Two teams of astronomers, working at Cambridge University and the US Fermi Laboratory in Batavia, Illinois, discovered them in images taken of the southern sky.
The scientists were searching for the so-called “dark matter” that makes up a quarter of the total matter and energy of the Universe.
Dwarf galaxies contain about 5,000 stars, compared with the hundreds of billions that make up the Milky Way, which is why they give off so little light and are so difficult to detect.
The closest of the nine is 95,000 light years away while the most distant is a million light years.
The Independent