[1] 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 [2]missing dark matter .

These atom-sized black holes "may fly through the inner solar system about once a decade, [3]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."

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> 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...

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> In a coincidence, an independent team published a paper about [4]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 [5]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."



[1] https://www.scientificamerican.com/article/dark-matter-black-holes-could-fly-through-the-solar-system-once-a-decade/

[2] https://science.nasa.gov/missions/hubble/mystery-of-galaxys-missing-dark-matter-deepens/

[3] https://journals.aps.org/prd/abstract/10.1103/PhysRevD.110.063533

[4] https://journals.aps.org/prd/abstract/10.1103/PhysRevD.110.063029

[5] https://www.scientificamerican.com/article/the-search-for-dark-matter-just-got-a-lot-harder/