Stars will continue to explode long after the universe is cold and “dead”, one scientist determined to dive into the rabbit hole to find the last supernova that will ever happen.
If the universe as we know it “dies”, it will be “a bit of a sad, lonely, cold place”, theoretical physicist Matt Caplan, an assistant professor of physics at Illinois State University, said in a statement. In a new study, Caplan calculated how dead stars could change over time and determined when the last supernova would explode in the distant future of the universe.
The end of the universe is “known as ‘heat death’, where the universe will be mostly black holes and burning stars,” Caplan explained in the statement. “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?”
Related: Supernova Photos: Large images of stellar explosions
It’s like saying the word ‘trillion’ almost a hundred times.
– theoretical physicist Matt Caplan
In the new study, Caplan looked at the future of stellar explosions. Massive stars explode in supernovae as iron builds up in their core, accumulating and triggering the star’s collapse. But smaller stars such as white dwarfs – ultra-dense star bodies that form like solar stars exaggerate all their nuclear fuel – do not have the weight and density to produce this iron. Caplan, however, found that over time, white dwarfs could become denser and become “black dwarf” stars that could actually produce iron.
“While white dwarfs will cool down over the next few trillion years, they will dimmer, eventually freeze and become ‘black dwarf’ stars that no longer shine,” Caplan said. “Stars shine because of thermonuclear fusion – they are hot enough to combine small nuclei to form larger nuclei, which releases energy. White dwarfs are ash, they are burnt out, but fusion reactions can still occur due to quantum tunneling, only much slower. ”
Quantum tunneling is a phenomenon in which a subatomic particle “tunnels” through a barrier seems impossible to penetrate when it disappears on the other side of the barrier reappears.
Caplan noted that this fusion is the key to making iron within black dwarfs and triggering this kind of supernova.
The new study shows how many iron black dwarfs of different sizes would need to explode. Caplan calculated that the first of these “black dwarf supernovae” would explode in about 10 to 1.1000 years – an almost unintentionally large number. “In years, it’s like saying the word ‘trillion’ almost a hundred times. If you spelled it out, it would take up most of a page. It’s mindbogglingly far into the future,” he said.
He found that the most massive black dwarfs would first explode, followed by fewer and fewer massive stars until no one was left, which he expected to be in about 10 ^ 3.2000 years. “It’s hard to imagine anything coming after that,” he said. “Black dwarf supernova is perhaps the last interesting thing that happens in the universe. They may be the last supernova ever.”
So what will the “sad, lonely” universe be like at this point, after the last supernova has exploded? According to Caplan, “Galaxies will have scattered, black holes will have evaporated, and the expansion of the universe will have pulled all the remaining objects so far apart that no one will ever explode any of the others. It will not even be physically possible for light to travel that far. “
This study was published August 7 in the Monthly Notices of the Royal Astronomical Society.
Email Chelsea Gohd at [email protected] or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.
