Sun will turn into giant crystal ball after death

Like the vast majority of stars in our Milky Way galaxy, the Sun will eventually collapse into a white dwarf, an exotic object about 200,000times denser than Earth. To put that in perspective, a mere teaspoon of white dwarf material would weigh about as much as an elephant if you could somehow transport the stuff to our planet.

Half a century ago theorists predicted that white dwarfs solidify into crystal over time – and new research has found that this is indeed the case.

“All white dwarfs will crystallise at some point in their evolution, although more massive white dwarfs go through the process sooner,” study lead author PierEmmanuel Tremblay, a physicist at the University of Warwick in England, said. “This means that billions of white dwarfs in our galaxy have already completed the process and are essentially crystal spheres in the sky,” Tremblay added. “The Sun itself will become a crystal white dwarf in about 10 billion years.”

Tremblay and his colleagues analysed data gathered by the European Space Agency's Gaia spacecraft which launched in December 2013 to help researchers construct the best-ever 3D map of the Milky Way. Gaia does this by precisely monitoring the positions of huge numbers of stars; the mission team aims to study 1 billion stars over the spacecraft's operational lifetime.

“This is the first direct evidence that white dwarfs crystallise, or transition from liquid to solid,” Tremblay said. “It was predicted 50 years ago that we should observe a pile-up in the number of white dwarfs at certain luminosities and colours due to crystallisation, and only now this has been observed.”