In the very, very distant future, cold stellar remnants known as black dwarfs will begin to explode in a spectacular series of supernovae, providing the last fireworks in history. That’s the conclusion reached by a new study published in the Monthly Notices of the Royal Astronomical Society, which posits that the universe will experience one last moment of glee before everything goes dark forever.
The end of the universe is a matter of vast speculation on the part of astronomers. Our understanding of cosmology and physics remains limited and the final scenario continues to adjust at each step to accommodate the latest hypotheses. Known laws of physics suggest that in about 10 ^ 100 years (a 1 followed by 100 zeros), star birth will cease, galaxies will darken, and even black holes will evaporate through a process known as Hawking radiation, leaving little more than simple subatomic particles and energy. The expansion of space will cool that energy to almost 0 kelvin, or absolute zero, indicating the heat death of the universe and total entropy.
Now Matt Caplan, assistant professor of physics at Illinois State University, has presented an interesting new scenario of how it could all end: in a deluge of black dwarf supernovae. A black dwarf is a cold white dwarf that has used up all its energy , slowly dissipating in the cosmos, since they do not produce their own energy by fusion like regular stars.
So based on this scenario, Caplan has theorized that as the universe continues to expand, at some point, it will run out of power. The gas in the universe, which is one of the main factors in the formation of new stars, will also be depleted. During this period (called the Great Freeze or heat death), the remaining stars will begin to die out and only the remnants of dead stars such as black holes, neutron stars, and white dwarfs will remain in the universe.
Since white dwarfs are not massive or dense enough to trigger supernova events like other stars, as we have seen, they will undergo a completely different reaction. According to Caplan, as white dwarfs become dimmer and cooler, they will eventually become “black dwarfs” stars.
” Stars less than 10 times the mass of the Sun do not have the gravity or density to produce iron in their cores as massive stars do , so they cannot explode in a supernova at this time,” Caplan explained. “As white dwarfs cool over the next trillions of years, they will become dimmer, eventually freeze, and become ‘black dwarf’ stars that no longer glow.”
If Caplan’s scenario is true, these black dwarfs could become supernovae, and it will be the last explosion in the universe before it is all over.
Yes indeed. Converting a white dwarf to a black dwarf takes a long time, so if protons disintegrate, black dwarfs are unlikely to form as white dwarfs would simply break apart on a shorter time scale. So, assuming the protons disintegrate /, the white dwarfs will become black dwarfs, and these will eventually become iron black dwarfs thanks to quantum phenomena that can create heavier atoms within the white dwarf . And this is where the real cosmic show begins . The collapse in a big bang. Imagine a billion trillion stars exploding in supernovae. By Caplan’s calculations, these cosmic fireworks will continue slowly but inexorably up to 1,032,000 years into the future.
Even if there were a time traveler who expected to witness this latest cosmic unfolding, he would be disappointed. For what reason? At the beginning of this era, the mysterious substance that acts in opposition to gravity called dark energy will have separated everything that exists in the universe so much that each individual black dwarf would be surrounded by vast darkness: supernovae would even be unobservable to each other.
Referencia: M E Caplan. Black Dwarf Supernova in the Far Future. Monthly Notices of the Royal Astronomical Society, 2020; DOI: 10.1093/mnras/staa2262
