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Space

Could Atom-Sized Black Holes Be Detected in Our Solar System? (scientificamerican.com) 59

Scientific American has surprising news about the possibility of black holes the size of an atom but containing the mass of an asteroid — the so-called "primordial black holes" formed after the birth of the universe which could solve the ongoing mystery of the missing dark matter.

These atom-sized black holes "may fly through the inner solar system about once a decade, scientists say... And if they sneak by the moon or Mars, scientists should be able to detect them, a new study shows." If one of these black holes comes near a planet or large moon, it should push the body off course enough to be measurable by current instruments. "As it passes by, the planet starts to wobble," says Sarah R. Geller, a theoretical physicist now at the University of California, Santa Cruz, and co-author of the study, which was published on September 17 in Physical Review D. "The wobble will grow over a few years but eventually it will damp out and go back to zero."

Study team member Tung X. Tran, then an undergraduate student at the Massachusetts Institute of Technology, built a computer model of the solar system to see how the distance between Earth and nearby solar system objects would change after a black hole flyby. He found that such an effect would be most noticeable for Mars, whose distance scientists know within about 10 centimeters. For a black hole in the middle of the mass range, "we found that after three years the signal would grow to between one to three meters," Tran says. "That's way above the threshold of precision that we can measure." The Earth-Mars distance is particularly well tracked because scientists have been sending generations of probes and landers to the Red Planet...

In a coincidence, an independent team published a paper about its search for signs of primordial black holes flying near Earth in the same issue of Physical Review D. The researchers' simulations found that such signals could be detectable in orbital data from Global Navigation Satellite Systems, as well as gravimeters that measure variations in Earth's gravitational field.

"For decades physicists thought dark matter was likely to take the form of so-called weakly interacting massive particles (WIMPs)," the article points out. "Yet generations of ever more sensitive experiments meant to find these particles have come up empty."

California astrophysicist Kevork Abazajian tells the site that now in the scientific community, "Primordial black holes are really gaining popularity."
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Could Atom-Sized Black Holes Be Detected in Our Solar System?

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  • Hmmm (Score:4, Interesting)

    by vbdasc ( 146051 ) on Sunday September 29, 2024 @11:30PM (#64827551)

    If these black holes are so small and so old, wouldn't the Hawking's radiation have destroyed them by now?

    • Yeah, I had the same question.
    • It depends on the size. Primordial black holes are generally described as having "about the mass of an asteroid". Initially there would have been smaller ones too, but any ones much smaller than that would have evaporated by now.

    • Re:Hmmm (Score:5, Informative)

      by ShanghaiBill ( 739463 ) on Monday September 30, 2024 @12:48AM (#64827613)

      If these black holes are so small and so old, wouldn't the Hawking's radiation have destroyed them by now?

      No.

      TFA says 10^17 to 10^23 grams.

      Even at the lower mass, the lifetime would be 1.5e18 years.

      That's a hundred million times the current lifetime of the universe.

      Hawking Radiation Calculator [vttoth.com]

      • Well, if it’s really 10^17 grams then one on the low end neglecting spin and charge would radiate 35kW heat in hawking radiation but also the Newtonian surface gravity alone is 3e27 m/s^2 so it’s going to massively generate heat from nearby particles going relativistic and tidally disrupting molecules like little stars and emitting the waste product at extreme energy levels nearby while also radiating into the surroundings (arguably so many orders of magnitude less it only matters visually to s
        • by HiThere ( 15173 )

          O, good. Someone who can criticize my theory.

          I propose that micro black-holes can never truly evaporate, because when they get small enough, they no longer have a large enough capture cross-section to swallow halves of virtual particles.

          If this isn't plausible, I'd like to know why.

          • Capturing and spitting out both would be affected by the cross section, or rather 3D shape, but hawking radiation is created by the unruh effect [wikipedia.org] and has to do with the curvature of the surface. As the radius and thus mass go to zero, the curvature drives outside observers to see it as high temperature. Because the temperature is proportional to 1/m or 1/r this ramps up to infinity. Now at lower energies most of what’s going to boil off are photons, but crank that power density past ludicrous and e
          • by qeveren ( 318805 )
            The "swallow one half of a virtual pair" is basically a tidy make-believe story of the Hawking radiation process. The actual process is much less intuitive and takes place well away from the event horizon (IIRC in the volume out to around 2 Rs), and can be boiled down to "the extreme gravitational field makes nearby and distant observers measure the vacuum in that region differently." That said there are hypotheses involving quantum effects that would prevent a black hole from evaporating completely once
    • by arfonrg ( 81735 )

      Yes... The smaller the black hole, the quicker it evaporates.

      "A black hole of one solar mass (M = 2.0×1030 kg) takes more than 10^67 years to evaporate—much longer than the current age of the universe at 1.4×10^10 years. But for a black hole of 10^11 kg, the evaporation time is 2.6×10^9 years."

      THE PART YOU CARE ABOUT: "This is why some astronomers are searching for signs of exploding primordial black holes. "

    • by Anonymous Coward

      Interesting things I learned when reading up on hawking radiation:
      For a 1-solar-mass black hole, the theoretical hawking radiation is practically undetectable. Think "single-digit photons per year." To put it another way, not a single particle of hawking radiation has been measured. The cosmic microwave background radiation of space is positively incandescent compared to the temperature of a solar mass black hole.

    • I think the "mass of an asteroid" is an overestimate. And I think that "Hawking radiation" is part of the reason why.

      Hawking radiation is caused when half of a pair of virtual particles is swallowed by a black hole. If the black hole is small *enough* it won't be able to capture anything. So I think that black holes never totally evaporate, they just get small enough that they can no longer capture halves of virtual pairs. Among other things, this eliminates the problems with "naked singularities". (Th

  • by banbeans ( 122547 ) on Sunday September 29, 2024 @11:32PM (#64827553)

    The answer is No.

    • I kind of concur.

      I don't think black holes with that mass can exist for even a second. If it takes a certain amount of mass for a black hole to occur naturally, i e several solar masses worth. Maybe it is possible to create one artificially with lower mass, but I think when a black hole evaporates to under a certain mass it will no longer be able to sustain itself and hence explode. At least that's what feels natural to me.

      But every now and again, I get to experience some things that turns out to be counter

      • Explodating black hole, it is possible that such an event would create an oscillating white hole - black hole object, that would be cool. Worth at least a 10 kilowords science fiction short story.

      • You can calculate the expected lifetime, and it's long enough. But the conditions to create such an object don't exist in the current time. Maybe it was possible in the early times? I'm just a lay person so I wouldn't know :)

        • Primordial [Re:No] (Score:5, Informative)

          by Geoffrey.landis ( 926948 ) on Monday September 30, 2024 @08:06AM (#64828101) Homepage

          You can calculate the expected lifetime, and it's long enough. But the conditions to create such an object don't exist in the current time. Maybe it was possible in the early times?

          Yes, that's why they're sometimes referred to as "primordial" black holes; they were (hypothesized to have been) created in the early universe, when it was still hot and dense, moments after the big bang.

          Whether the conditions of the early universe would in fact have created such black holes is still debated.

      • by Sique ( 173459 )
        There is quite a difference between "creating a Black Hole using solely the mass of an imploding star" and "creating a Black Hole". Cosmologists have figured out how an imploding star turns into a Black Hole. Today, this is the only mechanism we understand.

        But we know that supermassive Black Holes exist at the center of almost all galaxies, and cosmologists have no idea how those supermassive Black Holes formed. There are some hypotheses about them, but none of them is well established. But they are examp

        • I don't find supermassive black holes in the center of a galaxy at all strange. I think it's only a natural conclusion of what a strong gravitational force would do to a lot of nearby mass.
          In a three dimensional gravity image of a galaxy it's nothing more than a rotating funnel. If the glutton in the center has a lot of food it will get fat, unless the table is spinning the food away from it faster than it can suck it in.

    • Don't take offence, but what is the point of posting "No" as a rebuttal, with no accompanying reason? Are we supposed to just accept your declaration because you sound adamant? Are we supposed to recognize by your Slashdot account that you're some well-known astrophysicist? Christ man, make an effort or don't bother at all.
  • What is the difference in the impact on Mars between an asteroid-mass black hole and an asteroid of the same mass?

    Sure, we can detect some asteroids but space is vast and if you don't know exactly where to look and the asteroid is neither blocking something else nor reflecting energy in your direction, it's going to be pretty hard to detect.

    So, if you find a small change to Mars's orbit as described here, and you can't find an asteroid that might cause it, is it a black hole, is it an asteroid, or is it som

    • According to TFA, the upper bound is 10^20 kilograms, close to the size of the largest asteroids and a thousand times the mass of Phobos, the larger of the two Martian moons.

      There's no way we'd miss an asteroid of that size if it were close to Mars.

      • by unrtst ( 777550 )

        I hope this doesn't sound as dumb as injecting bleach, but this story made me wonder if primordial black holes might help explain our magnetic poles drifting or flipping. They're saying that we could detect a wobble if one zipped by... if it wobbled the earth, wouldn't it wobble the big, molten magnet at the center of earth even more?

    • by tragedy ( 27079 )

      Presumably a black hole this small in an impact with Mars would pretty much just punch a pinhole through the planet with both the black hole and the planet remaining relatively unscathed, but it's hard to say. The event horizon on the black hole would be so tiny, it's not going to do anything like start sucking in mass until it consumes the planet. It might be too small for individual atoms to even fit in the first place.

    • think about an atom, 'hitting' anything, at that size scale, it probably mostly is flying through empty space when it 'hits' Mars. It's gravitational pull, only so much as an asteroid, means it also doesn't gain much mass from this 'collision', sure, it may weigh (in some sense) many tons, but at the scale of atoms, it most likely will never really 'hit' anything/much of anything as it flies through Mars.
    • What is the difference in the impact on Mars between an asteroid-mass black hole and an asteroid of the same mass?

      Well, if an asteroid strikes Mars, the asteroid will be violently decelerated from its current speed to close to 0 relative to Mars. Most of the asteroid's kinetic energy will be absorbed by the planet, with very observable consequences. By contrast, (AIUI) an asteroid-mass black hole will interact very weakly with the planet; it will fly right through and continue on its way with almost the same speed. Since very little energy will be transferred, the effect on Mars of the "impact" should be almost negligi

  • CERN lab is isolating an atom size black hole at their super collider in Switzerland right now .. check out the live view: https://www.youtube.com/watch?... [youtube.com]

  • Maybe that's what caused that leap second drought a few years back.
  • I thought black holes sucked up everything that got close to them. Wouldn't these be sucking up matter and spewing xrays out the poles?
    Alternate question: what would happen if one of these went into (or through?) a planet?
    • by tragedy ( 27079 )

      Likely not a lot would happen. Remember, these black holes would be tiny. They only have the gravity of an asteroid, so at atomic scales they would have little gravitational effect on atoms sitting right next to them. So consuming a single atom would take a direct collision and they may be so small that would be very unlikely. It may even be possible that their event horizon is too small to even consume an atom. One could picture atoms that actually do get close enough to be caught in their gravity simply s

    • If it's small enough, it could feasibly orbit the center of mass of a planet without interacting too much. If the radius of the event horizon is small enough, it'll "eat" just one atom at a time and not grow in a meaningful way at any timescale that's relevant to us. Any radiation would be absorbed by the surrounding planetary material.

    • >I thought black holes sucked up everything that got close to them.

      While that is the popular depiction, it's entirely incorrect. Black holes do 'consume' anything that passes their event horizon (and do some nasty stuff to things that just get too close), but they 'suck' no more than the Earth does. Just like the ISS (or the Moon) haven't been sucked down to Earth, you can pass by a black hole and your course will bend without you falling in unless you're too close, too slow, or already heading straigh

    • It would be very bad. [space.com]

      The worst case is if it manages to lodge inside the planet. In that case, it would start pulling in matter from the planet, grow quickly, and eventually absorb the whole planet. No more Earth.

      Fortunately, that's considered very unlikely. Primordial black holes are expected to be moving really fast. Much more likely it would just punch a hole through and continue on its way.

      Unfortunately, that would still release a lot of energy. More than the asteroid that killed the dinosaurs. Yo

  • You need the mass of a large star to create the gravity required to form a black hole so how can something with the mass of an asteroid ever form? Have they radiated away most of their mass?

    • by sjames ( 1099 ) on Monday September 30, 2024 @06:01AM (#64827925) Homepage Journal

      These are primordial black holes formed when the big bang was fresh and the mean density (of both matter and energy) of the universe was quite high.

      While gravitational collapse is currently by far the most likely means that a black hole might form, and requires a mass larger than our sun to actually do it, there's no reason why in the hotter and denser early universe that something like a magnetic pinch couldn't force a smaller mass to a high enough density to become a black hole.

  • I had the same hypothesis in high school as a possible cause for my optical experiment not working as theory said it should. It was *obviously* primordial black holes the source of dark matter passing through the atmosphere gravitationally lensing my laser a small but sufficient amount to throw off the results. I had the calculations for the effect down and everything. "Sloppy experimental data collection my ass" It was black holes!
  • So far. not been found. So, could very likely not exist. https://www.sciencedaily.com/r... [sciencedaily.com]

    One should top inventing unicorns to make a man-made hypothesis work.
  • Where are Beowulf Shaefer, Carlos Wu and Sigmund Ausfaller when we really, really need them?

  • Hell, most tech CEOs fit this description. There, found them for you.

  • Obviously the result of a large celestial object passing through at near right angles to the plane of the star system... probably a black hole...

  • I've never really liked the notion of dark matter, and this is a very nice and elegant solution. I approve.

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