“This is the way the world ends,” TS Elliot said in his famous poem, “not with a slap, but with a trick.” These days, scientists consider the heat-death of the universe as the glider, but a new theoretical analysis predicts that the cosmos will inhale its definitive gasp in the form of exploding black dwarfs.
Trillions upon trillions of years from now, long after the last stars have been fizzled, the heaviest black dwarfs supernovae will begin to go, according to new research published in Monthly Notices of the Royal Astronomical Society. Black dwarfs are the frozen remnants of white dwarfs, which are even the remnants of low-mass stars. The sole author of the study, astrophysicist Matt Caplan of Illinois State University, says these explosions “will be the last interesting thing to happen in the universe” because he laid out in an ISU press release.
The universe could end a number of ways, but the current best judgment is that it will continue to expand long after everything inside it has been torn to shreds, including galaxies, solar systems, stars, and even atoms. By the time black dwarfs are set on pop, the universe will be “cold and lifeless,” Caplan wrote in an email to me.
“The expansion of the universe will have long since separated all the remaining objects by distances so enormous that no light will ever be able to reach each other,” he said. “Every object will find itself in a universe completely detached from something else in every direction. It will be cold and at absolute zero. ”
When existing stars go supernovae, it is at the expense of too much iron in their nuclei – the result of internal nuclear reactions. The same cannot be said for smaller stars, which eventually burn out and shrink into white dwarfs. According to theory, white dwarfs will eventually lose their luster and free in the distant future, with transition to black dwarfs.
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“Without a heat source, they simply cool down for all eternity, until they become ‘black’ and no longer sparkle,” Caplan said. “It’s a bit like taking a hot shell out of the oven – all it can do is cool.”
These hypothetical objects would be roughly the size of Earth, but with masses approaching those of our Sun. Importantly, nuclear reactions will still occur within these dense, frozen worlds, but at noticeably slower rates than normal. And as the new study predicts, these reactions will result in a slow build-up of iron, albeit on cosmologically large time scales. With this in mind, Caplan plotted the figures to estimate how long it would take for these black dwarfs to produce enough iron to trigger a supernova explosion.
The answer, at 10 p.m.1,100 years, is “hilariously long,” Caplan said. The age of the universe itself is closer to 1010 years, so if you were 10 you would try to write1,100 it would have 1,100 zeros and “take up most of a paragraph,” he explained. Or as Caplan put it in the ISU edition, “it’s like saying the word ‘trillion’ almost a hundred times.”
Importantly, these explosions occur only among the largest of the black dwarfs, namely those that are about 1.2 to 1.4 times the mass of the Sun. These supernovae – the last to ever occur in the universe – will eventually stop at 10 o’clock32,000 years from now, after which the cosmos will truly be a quiet and uneventful place.
Caplan said his analysis took into account the effects of an expanding universe. “If dark energy is different than we currently think, then the expansion of the universe could destroy the black dwarfs long before they have a chance to explode,” he said. What’s more, Caplan’s calculations were based on our current understanding of nuclear physics, astrophysics and cosmology, but to be honest, scientists can not be sure if the laws of physics and the universal constants in the distant future are the same. will remain. For example, it is possible that the universe does not even exist at this future moment.
“Some theories about particle physics predict that the proton is in principle unstable and will disappear, although this has yet to be observed or confirmed. If that is the case, then all matter will ‘evaporate’ long before black dwarfs explode, ‘Caplan said. ‘That’s just one example. In a way, our understanding of the distant future is entirely dependent on our understanding of the laws of physics today, and small changes in physics, as we know it, can have enormous consequences for the ultimate fate of it. universe and its contents. “
Although Caplan said that these black dwarf supernovae would be the “last interesting thing in the universe”, we asked him if anything of consequences if interest could happen after this phase.
“Depending on your definition of interesting,” he said. “If a cold iron ball floating in a universe where it is completely causally separated from all other objects is ‘interesting’, then I think you may find something of interest.”
Okay, honest point. But if there is any consolation in all this, it is that the universe will expand forever, at least according to some theories. It will be dead, cold and lifeless, but at least it will still be round.
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