The ever-increasing death toll due to coronavirus disease, Covid-19, has made a lot of us question our mortality. But even so, most of us are not overly worried about the end of the world happening any time soon.

And we can continue to rest easy since the expiry date of the universe is far away, though a scientist has calculated when and how the universe will end.

It will happen sometime over the “next few trillions of years”, according to theoretical physicist Matt Caplan. The end of the world as we know it, will not come with a bang. Most stars will “very, very slowly fizzle as their temperature fades to zero,” he says.

Describing it as “a bit of sad, lonely, cold place”, Caplan said in a statement that no one will be around to witness this long farewell happening in the far far future.

“It’s known as ‘heat death,’ where the universe will be mostly black holes and burned-out stars,” said the assistant professor of physics at Illinois State University, whose research has been published in the journal Monthly Notices of the Royal Astronomical Society.

In the research, Caplan looked at potential stellar explosions and found that even amid the darkness, there could be silent fireworks or explosions of the remnants of stars that were never supposed to explode. Many white dwarfs may explode in supernova when everything else in the universe has died and gone quiet. As they become denser, these stars will become “black dwarf” stars capable of producing iron in their cores.

According to NASA, a supernova is the explosion of a star while a white dwarf is a star near the end of its life that has used most or all of its nuclear fuel and collapsed into a size similar to Earth.

“Stars less than 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,” said Caplan. “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 cannot be burned by stars, it accumulates like a poison, triggering the star’s collapse creating a supernova.

According to Caplan’s calculations, the theoretical explosions which he calls “black dwarf supernovas”, will begin to occur in about 10 to the 1100th years.

“In year, it’s like saying the word ‘trillion’ almost a hundred times,” he said.

And not all black dwarfs will explode either. Caplan said only the most massive black dwarfs, about 1.2 to 1.4 times the mass of the sun, will blow.”

In numbers, this means that as many as one percent of all stars that exist today, about a billion trillion stars, will blow up this way.

Caplan has calculated that the most massive black dwarfs will explode first, followed by progressively less massive stars, until there are no more left to go off after about 10^32000 years. At that point, the universe may truly be dead and silent.

“It’s hard to imagine anything coming after that, black dwarf supernova might be the last interesting thing to happen in the universe. They may be the last supernova ever,” he said.