Scientist calculates the ‘sad, lonely’ end of the universe
Stars will continue to explode long after the universe is cold and ‘dead’, one scientist determined after diving down the rabbit hole to find the last supernova that will ever happen. The universe’s end is “known as ‘heat death,’ where the universe will be mostly black holes and burned-out stars,” said Matt Caplan, an assistant professor of physics at Illinois State University. “I became a physicist for one reason. I wanted to think about the big questions – why is the universe here, and how will it end?”
Caplan looked to the future of stellar explosions. Massive stars explode in supernovae when iron builds up in their cores, accumulating and triggering the star’s collapse. But smaller stars such as white dwarfs – ultradense stellar corpses that form when Sun-like stars exhaust all of their nuclear fuel – don’t have the gravity and density to produce this iron. However, Caplan discovered that over time white dwarfs might become denser and become ‘black dwarf’ stars that can actually produce iron.
Caplan calculated that the first of these ‘black dwarf supernovae’ will explode in about 1011,000 years – an almost inconceivably large number. “In years it’s like saying the word ‘trillion’ almost a hundred times. If you wrote it out, it would take up most of a page. It’s mind-bogglingly far in the future,” he said.
He found that the most massive black dwarfs will explode first, followed by less and less massive stars until there are none left, which he expects will be in about 1032,000 years. “It’s hard to imagine anything coming after that,” he said. “Black dwarf supernovae might be the last interesting thing to happen in the universe. They may be the last supernova ever.”