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The end of the universe may be marked by 'black dwarf supernova' explosions

supernova
An image of the Kepler supernova remnant, captured with NASA's Chandra X-Ray Observatory. A different type of stellar explosion, called a black dwarf supernova, may light up the darkness at the end of the universe.
(Image: © Image credit: NASA/CXC/Univ of Texas at Arlington/M. Millard et al.)

At the end of the universe, long after the last shining stars flicker out, there might be one final set of explosions. Called black dwarf supernovae, these dazzling blasts will herald in the everlasting darkness as the universe sinks into dormancy, a new study suggests.

These newly proposed supernovas are a special breed that haven't yet happened anywhere in the universe. Black dwarf supernovas might be the last events that happen in the universe, which by then will be a largely empty place where the temperature approaches absolute zero. 

Stars' lives and deaths are determined by their mass. Large ones 10 or more times the mass of the sun explode as supernovas and can become black holes. But smaller ones, which don't produce heavier elements through the nuclear fusion at their cores, end their lives as small dense husks of stars known as white dwarfs. Over trillions of years, they dim and turn into frozen, lightless objects known as black dwarfs. A new paper, to be published in the journal Monthly Notices of the Royal Astronomical Society, describes how these black dwarfs may ultimately release the final bits of light in the universe as they explode as supernovas.

Related: 15 amazing images of stars

The black dwarf supernovas would form through a quantum process known as pycnonuclear fusion. Stars are normally fueled by thermonuclear fusion, where high temperatures and pressures overcome atomic nuclei's natural electric repulsion, allowing atoms to fuse into new, heavier elements. But in pycnonuclear fusion, quantum tunneling allows atomic nuclei to get closer to each other than they normally would. Pycnonuclear fusion can thus very slowly turn the elements in the white dwarf into iron –- the last element that can be created by fusion. 

"These reactions take an insanely long time," said study author Matt Caplan, theoretical physicist at Illinois State University. "You could wait a million years and not see a single fusion reaction in a black dwarf."

By comparison, the sun fuses more than 10^38 protons per second. To convert a black dwarf into iron by pycnonuclear fusion would take  a mind-boggling 10^1,100 and 10 ^32,000 years. If you wrote out all the zeros in these numbers, they'd take up the length of a paragraph to a whole book chapter, respectively. 

"These time scales are enormous," said Fred Adams, astrophysicist at the University of Michigan, who was not involved in the new research. "We expect the largest possible black holes to be evaporated on time scales of only about 10 to the 100 years, which is instantaneous compared to the times discussed in the paper."

Once the black dwarf was mostly iron, it would be crushed by its own mass. This runaway collapse — the supernova — would trigger a huge implosion that ejects the outer layers of the leftover black dwarf. In larger stars today, this iron pileup is also what leads to the more common so-called core-collapse supernovas.

Black dwarf supernovae, however, would only occur in black dwarf stars with masses between 1.16 and 1.35 times that of the sun. Those black dwarf stars are in turn created from typical stars that start off with six to 10 times the mass of the sun. 

"[It] is not exactly a rare population, but also not the most common," Caplan said. 

In fact, these stars make up about 1% of all stars today, and Caplan estimates there will be about a billion trillion (10^21) of these supernovae before the end of the universe. Since the black dwarfs have fairly low masses, the black dwarf supernovas would probably be a bit smaller than ones occurring in the present universe, but still spectacular in an otherwise pitch-black universe. 

After these final last gasps of light, nothing left in the universe will be able to explode or shine. So while the universe will seemingly end in ice, there will be a spark of fire along the way. 

Originally published on Live Science.

  • Xinhang Shen
    Now, how can people talk about the entire universe while they just know an extremely tiny bit of the universe? Actually, all the theories of modern physics are wrong: relativity, quantum mechanics, QFT, big bang theory, string theories, etc. Based on these non-senses, many people even boast that they have known everything in the universe through the formulation of the theory of everything. Is it funny?

    The fatal mistake of relativity is that it introduces a new set of artificial space and time defined through Lorentz Transformation to replace the real physical space and time measured with rulers and clocks (see https://www.researchgate.net/publication/297527784_Challenge_to_the_Special_Theory_of_Relativity ). Relativity leads physicists to believe in spacetime, time travel, expansion of spacetime, singularities of spacetime, worm holes, ripples of spacetime, gravitational lensing, big bang, etc. Relativity denies the existence of aether - a fluid medium of light delivering all electromagnetic phenomena in the visible part of the universe around us. Without aether as the medium to describe the wave property in the particle-wave duality, physicists couldn't but invent a mathematical concept: the wave of probability to represent the physical reality - the wave of aether, which leads to the birth of the preposterous quantum mechanics with all the ridiculous conclusions: quantum entanglement, Schrodinger's cat, denial of local reality, etc. According to these theories, there would be no facts and no truth in the universe because every fact could be changed through time travel, and every truth would depend on the observer. Then, there is no objective science at all!!!
    Reply
  • Valentine Michael Smith
    Uh-ohh..... 297 784

    Or should we say, 'Rut Ro!'
    Reply
  • Chem721
    Xinhang Shen said:
    Based on these non-senses, many people even boast that they have known everything in the universe through the formulation of the theory of everything.


    The closest we can come to a theory of everything is the following:

    E = mc2

    It is difficult to find a more inclusive concept with such a firm foundation in reality.
    Reply
  • Nytowl223
    Xinhang Shen said:
    Now, how can people talk about the entire universe while they just know an extremely tiny bit of the universe? Actually, all the theories of modern physics are wrong: relativity, quantum mechanics, QFT, big bang theory, string theories, etc. Based on these non-senses, many people even boast that they have known everything in the universe through the formulation of the theory of everything. Is it funny?

    The fatal mistake of relativity is that it introduces a new set of artificial space and time defined through Lorentz Transformation to replace the real physical space and time measured with rulers and clocks (see https://www.researchgate.net/publication/297527784_Challenge_to_the_Special_Theory_of_Relativity ). Yadda yadda, blah blah blah ...
    So, I'm guessing no one has yet told you that the "electromagnetic universe" or "plasma cosmology" "theory" (more like hypothesis, because facts) is nothing more than total nonsense. For starters, the hypothesis doesn't predict Hubble's Law, the relative abundances of the elements, or the cosmic microwave background. And that's JUST for starters. It's total bunk. And that's putting it nicely.
    Reply
  • Chem721
    Nytowl223 said:
    It's total bunk. And that's putting it nicely.

    You have such patience to put this stuff in context. Most commendable.

    Very disappointing since the first sentence was a really good question, but followed by "total bunk".
    Reply
  • Xinhang Shen
    Nytowl223 said:
    So, I'm guessing no one has yet told you that the "electromagnetic universe" or "plasma cosmology" "theory" (more like hypothesis, because facts) is nothing more than total nonsense. For starters, the hypothesis doesn't predict Hubble's Law, the relative abundances of the elements, or the cosmic microwave background. And that's JUST for starters. It's total bunk. And that's putting it nicely.
    All I said is that relativity has denied the existence of aether that misled other physics theories. The disproof of relativity directly leads to the existence of aether - a fluid medium of light, only relative to which, the speed of light is isotropic. There is no such a law (Hubble's Law) in nature, which is just a local approximation. The visible sky is more likely a collection of celestial objects in an oscillation process: all objects are currently in the stage of accelerating expansion as the pressure of aether dominates, which will be followed by a stage of decelerating expansion when gravitation dominates, then the stage of accelerating implosion, followed by the stage of decelerating implosion until it reaches the minimal volume. After that, a new cycle will start. With the existence of aether, it is more likely that the pressure of aether pushes galaxies moving away from each other in acceleration during the current stage, that the gravitation of aether as the extra pulling binds stars in galaxies, that the viscosity of aether dissipates the visible light into microwaves in the background, that the density change caused by the gravitation of massive celestial objects produces the effect of gravitational lensing. We know the universe is far more complicated than what we can imagine. Aether is just one of the missing players in the space, with which many phenomena (but never means all phenomena) can be more reasonable explained.
    Reply
  • TorbjornLarsson
    Xinhang Shen said:
    Now, how can people talk about the entire universe while they just know an extremely tiny bit of the universe?

    Because cosmology tells us we can describe the entire universe in a model https://en.wikipedia.org/wiki/Lambda-CDM_model ].

    Xinhang Shen said:

    Actually, all the theories of modern physics are wrong: relativity, quantum mechanics, QFT, big bang theory, string theories, etc.

    Claimed without giving any evidence or references to peer reviewed work.

    Instead you troll a self promoting "essay" from a predatory journal - we've been here before, and your comment is no less trolling than the last time.
    Reply
  • TorbjornLarsson
    Nytowl223 said:

    So, I'm guessing no one has yet told you that the "electromagnetic universe" or "plasma cosmology" "theory" (more like hypothesis, because facts) is nothing more than total nonsense. For starters, the hypothesis doesn't predict Hubble's Law, the relative abundances of the elements, or the cosmic microwave background. And that's JUST for starters. It's total bunk. And that's putting it nicely.

    Xinhang Shen said:

    All I said is that relativity has denied the existence of aether that misled other physics theories.

    Good guess Nytowl223, since the "electric universe" pseudoscience usually denies relativity and promote mythological "aether" too https://en.wikipedia.org/wiki/Aether_(classical_element) ]. But there is also an old pseudoscience cottage industry that promotes the classic superstition despite that it has been rejected by experiment over a century ago https://en.wikipedia.org/wiki/Michelson-Morley_experiment ].

    But of course general relativity is by now the only known game in town.
    When combined with Planck Cosmic Microwave Background (CMB) measurements of temperature and polarization the BAO data provide nearly an order of magnitude improvement on curvature constraints. The RSD measurements indicate a growth rate that is consistent with predictions from Planck primary data and with General Relativity. When combining the results of SDSS BAO and RSD with external data, all multiple-parameter extensions remain consistent with a ΛCDM model. Regardless of cosmological model, the precision on ΩΛ, H0, and σ8, remains at roughly 1\%, showing changes of less than 0.6\% in the central values between models.
    https://arxiv.org/abs/2007.08991 ; my bold.]
    Reply
  • David J Franks
    TorbjornLarsson said:
    Because cosmology tells us we can describe the entire universe in a model https://en.wikipedia.org/wiki/Lambda-CDM_model ].



    Claimed without giving any evidence or references to peer reviewed work.

    Instead you troll a self promoting "essay" from a predatory journal - we've been here before, and your comment is no less trolling than the last time.
    Because cosmology tells us we can describe the entire universe in a model
    This is a bold claim.

    Anyway, what do you mean by 'universe' and 'entire universe'? Is this claim for the observable 'contents of the big bang' or the 'whole contents of the big bang' or the universe (dictionary definition).

    The dictionary definition of 'universe' is "everything that there is". You, this web sites articles and most top scientists seem to keep referring to the big bang and the universe as one and the same thing. for example, statements like - "The universe started with the big bang". It is a huge assumption that the contents of the big bang are 'everything that is' ie the universe. There's absolutely no evidence to support this, I find it completely unscientific.

    So until proven otherwise I think its equally good (no, better) to assume the universe is infinite and contains infinite 'stuff'. Meaning the contents of the Big bang is not 'everything that is' ie the universe. With this in mind, the contents of the big bang are expanding into the stuff of rest of 'The Infinite', as I like to call it. When it hits this 'stuff', the 2nd law will not be able to expand the contents of our big bang anymore. So no heat death!

    Everything that exists, exists in a space. The big bang may have created space (space itself being a 'something' eg quantum foam etc), but at the same time, it must have existed in a space, even if just a void or geometric space. So, if you want to stick with the idea that the contents of the big bang is also the universe, you are assuming that the rest of space that the big bang existed in is infinite and void, in order to allow indefinite expansion and heat death. A bit absurd in my opinion.

    For something to have a beginning, it must be a part of a greater whole or from something pre-existing, otherwise, it's just another something from nothing theory." Again with this proposition the contents of our big bang are expanding into the greater whole, and so can't expand forever - no heat death.

    Altogether, with unknown dark energy, and the possibility that the contents of the big bang are expanding into a 'greater whole' or 'The Infinite', don't you think it's a bit unsafe to predict the end, (heat death) of 'everything that there is' just yet?

    The observation of the accelerating expansion of the universe is explained with dark energy. We don't know what dark energy is or its full properties. Support for the end of the universe is dependent on something we know nothing about or even if it exists at all. Don't you think that something as important as the end needs something a bit more concrete than an unknown 'dark energy'?:)
    Reply
  • Xinhang Shen
    TorbjornLarsson said:
    Because cosmology tells us we can describe the entire universe in a model https://en.wikipedia.org/wiki/Lambda-CDM_model ].



    Claimed without giving any evidence or references to peer reviewed work.

    Instead you troll a self promoting "essay" from a predatory journal - we've been here before, and your comment is no less trolling than the last time.
    Please check Wikipedia before making your irresponsible claim:

    Physics Essays is a peer-reviewed scientific journal covering theoretical and experimental physics. It was established in 1988 and the editor-in-chief is E. Panarella.

    You just can't refute the paper, but instead, defame the journal! How mean and shameless!
    Reply