Using superconducting gravimeters to search for compact dark matter objects

Exploring how compact dark objects (CDOs) interact very weakly with normal matter.

Dark matter could be composed of compact dark objects (CDOs). These objects may interact very weakly with ordinary matter and could move freely inside the Earth.

Detecting dark matter has so far ended up being inconceivably challenging, yet it could be far simpler if this type of issue were concentrated into macroscopic objects. A few physicists have recommended that dark matter, or least of a component of it, might be comprised of compact dark objects (CDOs), which are expected to display small nongravitational connections with normal matter.

Charles Horowitz and Rudolf Widmer-Schnidrig, two scientists at Indiana University and the Black Forest Observatory (BFO) in Germany, individually, have conducted an examination exploring the use of gravimeters to scan for compact dark matter objects (CDOs) inside the Earth. Their study features the capability of utilizing superconducting gravimeters in the progressing look for dark matter.

Horowitz said, “Much of the universe is made of unknown dark matter. In our previous work, we searched for clumps of dark matter, which we call compact dark objects, CDOs, in neutron stars, or the sun. Since dark matter may interact very weakly with normal matter, it can move about inside normal bodies in ways that conventional matter can’t.”

Astronomy theory proposes that dull issue has gravitational interactions with ordinary matter. Looking for CDOs utilizing tools that can detect differences in gravitational forces between one location and another in this manner appears to be a promising option.

Keeping this in mind, scientists investigated the potential of gravimeters for searching CDOs. On Earth, the acceleration due to gravity is approximately g(t) = 9.8 m/s2, while a gravimeter can measure changes in this number in the 12th digit to about 12 digits.

Horowitz said, “Gravity from a CDO will change the value of g slightly as the CDO moves closer to or away from the gravimeter. We look for a time dependence to g(t) that changes with the 55 minutes of the CDO’s orbit inside the Earth.”

Scientists calculated that CDO moving in Earth’s inner core would have an orbital period of almost 55 minutes, and would produce a time-dependent signal in a gravimeter. The data they collected using superconductive gravimeters, however, rules out the presence of such objects inside the Earth’s core, unless these objects have a shallow mass or small orbital radius.

In the future, scientists are planning to repeat their study using gravimeters with higher sensitivity. Their work could also inspire physicists at other institutions worldwide to carry out similar experiments using gravimeters.

Horowitz said, “We have shown how to use the sensitivity of gravimeters to probe for one possible form of dark matter. We demonstrated that no such objects are moving inside the Earth unless their mass and or orbital radius is very small. In our future work, we plan to try and improve the sensitivity of our search and to search for CDO in other solar system bodies, possibly.”

Their paper published in Physical Review Letters.

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