In the incredibly distant future, the explosion of a still hypothetical object could well seal the fate of our Universe.
The Big Freeze is one of the possible destinies of the universe. The laws of physics as we know them suggest that in the very distant future, no more stars can be formed. The galaxies will then become dark and the black holes will eventually evaporate. Eventually, the temperature of the universe will finally approach absolute zero, confirming its thermal death.
“It will be a bit of a sad, lonely and cold place ”, explains theoretical physicist Matt Caplan of Illinois State University. Still, that heralded ending might not be the end after all. The physicist was in fact interested in the future, in this universe, of still hypothetical objects.
Black dwarfs
In the universe, massive stars end their lives in supernova explosions. These occur when internal nuclear reactions start to produce iron in the nucleus. And iron, unlike other elements, cannot be starched. It then accumulates in the nuclei like a poison, ultimately triggering the collapse of the star.
For their part, less massive stars, like the Sun, bow out with a little more discretion. They lose their outer envelopes and eventually shrink and become white dwarfs. Mostly made of light elements like carbon and oxygen, these objects are the size of the Earth, but contain about as much mass as the Sun.
The theorist then suggests that as white dwarfs get colder over the next few trillion years, they will become darker and darker, eventually turning into “black dwarf” stars that do not. will shine more.
However, all will not end. Caplan’s hypothesis, roughly, proposes that over long periods of time, quantum mechanics would allow particles to cross energy barriers, ultimately allowing nuclear fusion reactions.
“These objects will only be ash, but fusion reactions may still occur.“, Explains the researcher. “It just takes a lot longer“.
The last explosion
This new work, accepted for publication by Monthly Notices of the Royal Astronomical Society, theorizes as well as the black dwarfs whose mass is between 1.2 and 1.4 times the mass of our Sun could eventually collapse on themselves and end their life in an explosion similar to that of a supernova. According to the specialist, around a billion billion stars can be expected to die this way. As for the others (the less massive), they will remain black dwarfs.
These black dwarf explosions could start from here, Matt Caplan says 101100 years. It is nevertheless difficult to apprehend such a duration. “It’s unbelievably far into the future“, Writes the researcher.
By the time these objects explode, the universe will already be unrecognizable. “The galaxies will already have dispersed and the black holes will have evaporated ”, notes the researcher. These explosions will thus be done in the greatest discretion.
Caplan also calculates that the more massive black dwarfs will explode first, followed by the less massive ones, until only one remains. According to him, this latest black dwarf supernova explosion could take place in 1032000 years. At this stage, according to him, the universe can then be considered as really dead and silent.
“It’s hard to imagine anything after this, this supernova could be the last interesting thing to happen in the universe. ”, Concludes the physicist. “It will undoubtedly be the last supernova of all time ”.
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