There is a huge halo of gas circling our Galaxy with the mass of a billion Suns.
Stripped from the two dwarf Magellanic galaxies that orbit the Milky Way, the enormous stream of gas spreads over more than a quarter of the southern night sky.
Yet it is only now that astronomers can explain why the Magellanic Stream persists and is as massive as it is.
The researchers publish their findings in the journal Nature.
Over billions of years, the Milky Way has captured smaller galaxies in its orbit and the two largest are known as the Small and Large Magellanic Clouds.
Easily visible to the naked eye in the Southern Hemisphere, they are home to billions of stars and circle each