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Zorro

(16,296 posts)
Tue Sep 17, 2024, 08:30 AM Sep 17

Are tiny black holes zipping through our solar system? Scientists hope to find out.

A mind-bending hypothesis is gaining traction among scientists: The universe may be teeming with microscopic black holes the size of an atom, but with the mass of a city-sized asteroid.

Created just a split second after the Big Bang, these hypothetical black holes would whip quietly through the solar system roughly once every few years, traveling over a hundred times faster than a bullet.

Some have even argued that an immense explosion that flattened a Siberian forest in 1908 could have been the result of one of these micro black holes impacting Earth.

Now, researchers say they’ve figured out a way to test whether these cosmic bullets truly exist.

In a study published Tuesday in the journal Physical Review D, physicists at MIT say the presence of a tiny black hole speeding through the solar system could be identified by the gentle gravitational nudge it exerted on the Earth and other planets, which would alter their orbital paths by no more than a few feet.

https://www.latimes.com/science/story/2024-09-17/tiny-black-holes-zipping-through-the-solar-system

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Martin68

(24,611 posts)
2. An asteroid with the mass of a "city-sized asteroid" would move the Earth by a few feet?
Tue Sep 17, 2024, 11:43 AM
Sep 17

I find that surprising considering the mass of the Earth compared to a city-sized asteroid. Is this accurate? If it is, how close would it have to come to the Earth's surface to have that effect? Gravitational force is inversely proportional to the square of the distance.

Jim__

(14,456 posts)
4. A version of the paper is available on arXiv.
Wed Sep 18, 2024, 10:45 AM
Sep 18
Here

The argument is that such perturbations would be too small to be currently detectable, but improved instruments may allow such detection in the future.

The abstract from the paper:


ABSTRACT
If primordial black holes (PBHs) of asteroidal mass (MPBH [in] [1017, 1023] g) make up the entire
dark matter they could be detectable through their gravitational influence in the solar system. In
this work we study the perturbations that PBHs induce on the orbits of planets. Detailed numerical
simulations of the solar system, embedded in a halo of primordial black holes, are performed. We show
that the perturbations are too small to be directly detectable with current data, challenging recent
results that have ruled out PBHs as a dark matter candidate. Using the Earth-Mars distance as an
observational probe, we estimate that an improvement in the measurement accuracy by more than an
order of magnitude is required to detect the gravitational influence of PBHs in the solar system in the
foreseeable future.


Martin68

(24,611 posts)
5. So is the suggestion that it would move the earth "a few feet" a guess, an exaggeration, or based on the math?
Wed Sep 18, 2024, 11:32 AM
Sep 18

Jim__

(14,456 posts)
6. They're not looking at single encounters, but rather at simulations of cumulative effects over years.
Wed Sep 18, 2024, 01:16 PM
Sep 18

And, they don't talk about it in terms of feet, but rather in terms of (delta ⁢r) / r(t) where r is the approximate distance between earth and another solar system object.


From the paper:



Finally, Figure 3 presents the results from 500 simulations performed over a longer time span of 20 years for MPBH=1020 g. In the left panel we display the perturbation |delta ⁢𝕣|/r of the vector between Earth and Mars. A notable difference to Figure 1 is that the perturbations oscillate with a period of roughly two years which corresponds to the synodic orbital period of Mars and is thus simply a result of the change of r. We add an estimate for a 3⁢σ detection limit by assuming that sigma r≈70 cm for the Earth-Mars distance (Park et al., 2021). Out of all 500 simulation runs only 4 exceed this limit at least once within 20 yrs, implying a ∼1% chance of detection with a confidence level of 3sigma.

In the right panel of Figure 3 we show the mean perturbation strength |delta ⁢𝕣|/r of all simulation runs for several planets. In our analysis we focus on the Earth-Mars pair for the reasons outlined in Section 2. The results shown here demonstrate that this does not limit the generality of our statements as the observed perturbations are very similar for other planets in the solar system.



Figure 3: Left: Perturbation of the vector between Earth and Mars induced by PBHs for MPBH=1020 g as a function of time. Each blue line corresponds to one simulation run. We only show 100 simulation runs to improve readability. The black dashed/dotted line indicates the median/mean value obtained from all 500 simulations. The analytical result of the impulse model is displayed as an orange line. The green line shows a model for the median perturbation strength, given by Equation 15. The red line is an estimate of the 3⁢ sigma observational detection limit. Right: Mean perturbation strength |delta ⁢𝕣|/r as a function of time for the vector between Earth and various planets.

Martin68

(24,611 posts)
7. The quote I was referring to was clearly referring to the effect of only one black hole, and it specifically refers to
Wed Sep 18, 2024, 03:07 PM
Sep 18

a distance measured in feet. "...physicists at MIT say the presence of a tiny black hole speeding through the solar system could be identified by the gentle gravitational nudge it exerted on the Earth and other planets, which would alter their orbital paths by no more than a few feet." I find that statement hard to believe and wonnder if it isn't a mistake.

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