The Hubble Space Telescope has discovered that a peculiar little galaxy is one of the most incredible examples of galaxies with extremely low metal content. This suggests that the chemical composition of the galaxy has hardly changed in more than 13 billion years.
Shortly after the Big Bang, only hydrogen and helium were present in the universe. All other elements, called metals in astrophysics, were formed after the very first stars burst into supernovae. These supernovae «polluted» the parent galaxies and led to the formation of new stars and planetary systems.
But the Peekaboo galaxy hasn’t experienced much of this, and for that reason has remained metal-poor all this time.