At the end of its life, our Sun could end up as a crystal — and physicists now have observational evidence to back up that theory
Scientists have predicted that as white dwarfs cool, they can crystallize in a transition somewhat like water freezing into ice. New research from scientists in the UK, U.S., and Canada provides evidence of this transition in a survey of nearby white dwarfs. This is especially interesting for us, as we've reported, scientists predicted that our own Sun is a white dwarf.
White dwarfs are small, faint, and incredibly dense stars, the results of stars like the Sun Running out of the fuel that powers their nuclear fusion. They have masses around that of the Sun but are only around the size of the Earth. They consist of a packed plasma of atoms and their electrons. The electrons are forbidden from sharing exact states by the rules of quantum mechanics, so they exert a pressure that keeps the stars from collapsing.
Though they're plasmas, scientists have long predicted that these squished atoms should eventually crystallize, beginning at the stars' centers. There has been indirect observation of the crystallization, but scientists now claim to have observed the process directly. They describe their findings in a paper published in Nature
Models suggest that when white dwarfs crystallize, they release heat in order to enter the lower-energy phase, the way heat energy leaves water when it freezes into ice. This would slow down the star's cooling, and an effect that scientists can observe directly.
The team analyzed a catalog of 15,109 white dwarf candidates within 100 parcels (326 light-years) of our Sun using data from the Gaia satellite. And indeed, they found a "pile-up" of stars at certain locations along a plot of color versus brightness. That's evidence of stars going through the phase transition from plasma to crystal, according to the paper.
Obviously, this is dependent on modeling, and perhaps other explanations could explain the data better. But it's exciting stuff — this would imply that many white dwarfs could be considered more than scientists, since the crystallization slows the aging process.
And one day our Sun, too, may be a beautiful crystal ball. And we'll be dead.