Astronomers have discovered a 'two-faced' star, one side is composed almost entirely of hydrogen and the other side is made up of helium. The discovery is a first among white dwarf stars.

This lifespan began roughly 4.6 billion years ago, and will continue for about another 4.5 - 5.5 billion years, when it will deplete its supply of hydrogen, helium, and collapse into a white dwarf.