It will happen sometime over the “next few trillion years”
It’s not expected to happen anytime soon, but one scientist has calculated when the universe will end.
The research, published in the journal Monthly Notices of the Royal Astronomical Society, notes that sometime over the “next few trillion years,” when the universe is dead as we know it, stars will continue to explode, not with a giant bang, but “very, very slowly fizzle.”
“It [the universe] will be a bit of a sad, lonely, cold place,” the study’s lead author, theoretical physicist Matt Caplan, said in a statement. “It’s known as ‘heat death,’ where the universe will be mostly black holes and burned-out stars.”
In the research, Caplan looked at potential stellar explosions and found that white dwarfs will explode in a supernova in the future. As they become denser, these stars will become “black dwarf” stars capable of producing iron in their cores.
“Stars less than about 10 times the mass of the sun do not have the gravity or density to produce iron in their cores the way massive stars do, so they can’t explode in a supernova right now,” Caplan explained. “As white dwarfs cool down over the next few trillion years, they’ll grow dimmer, eventually freeze solid, and become ‘black dwarf’ stars that no longer shine.”
Since iron can’t be burned, it will accumulate, similar to a poison, and trigger the collapse of the star and become a supernova. Caplan estimates the first one of these theoretical explosions will happen in about 10 to the power 1100 years. “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,” Caplan added. “It’s mindbogglingly far in the future.”
Nonetheless, all the stars that turn into black dwarfs will not explode, just those that are between 1.2 and 1.4 times the mass of the sun, or approximately 1% of all stars that currently exist, Caplan pointed out.
The other approximately 99% of stars will remain black dwarfs.
The largest black dwarfs will go supernova first, followed by smaller ones, at which time the universe will likely be a giant emptiness, completely unrecognizable.
“It’s hard to imagine anything coming after that, black dwarf supernova might be the last interesting thing to happen in the universe,” Caplain stated. “They may be the last supernova ever. Galaxies will have dispersed, black holes will have evaporated, and the expansion of the universe will have pulled all remaining objects so far apart that none will ever see any of the others explode. It won’t even be physically possible for light to travel that far.”
Researchers continue to learn more about the state of the universe. In July, a separate group of experts suggested the universe could be as much as 1.2 billion years younger than the 13.8 billion years old it is widely assumed to be.