Scientists in Denmark have been studying distant galaxies, which are among the most active star-forming galaxies in the Universe. They form around 1,000 new stars a year — a 1,000 times more than our own galaxy, the Milky Way. The galaxies are located in the far distant Universe — when the Universe was 3 billion years old. It is a period when the galaxies were very active, almost teenager-like and out of control.