One of the cosmology’s greatest unsolved mysteries is the nature of dark matter, a mysterious and invisible substance that dominates over 20 percent of the universe’s observable mass. But recent findings by Princeton U’s Shravan Hanasoge, a post-doctoral student in the geosciences department, and New York Princeton’s Michael Kesden about primordial black holes — theoretical remnants of the Big Bang and one of a handful of potential sources for dark matter — may give scientists a new way to unlock the secrets of the elusive substance.

Hanasoge and Kesden have uncovered a new method for detecting collisions between stars and primordial black holes, which may provide concrete, observable proof of the existence of dark matter. Primordial black holes are several magnitudes smaller than the more widely-known stellar black holes. The scientists found that because of the diminished mass, a primordial black hole does not swallow up a star in a collision as would a stellar black hole.

Instead, the gravity of a primordial black hole squeezes the star and causes vibrations on the star’s surface as it snaps back into place after the black hole has passed through — and the ability to detect these vibrations could lead astronomers to finally observe a black hole.

“The hope is that the vibrations caused … are unique,” Hanasoge said. “If you were able to conclusively see a primordial black hole, this would have profound consequences in our understanding of early universe cosmology and dark matter.”

But the discovery, according to Kesden, is still only a “preliminary” step in actually identifying a primordial black hole. A primordial black hole passing through a star such as the sun is a very rare event — one that happens once every 10 million years, Kesden said. Given such a low frequency of occurrence, Kesden admitted that the team’s ideas may not be entirely practical and that they now need to determine whether their stimulations can be applied to stars other than the sun.

“Since other stars are so much further away [than the sun] and we cannot see them with as much detail, we need to do calculations that can handle these larger scales,” Kesden said. He noted that the staggering number of stars in the galaxy means it is likely that every so often a black hole could be seen passing through a star if a sufficiently large sample of stars was observed.

“However, having said that much, it is as hard as it is impressive to do it,” Hanasoge said of their endeavor.

To make their models, Hanasoge and Kesden simulated and diagrammed the waves and oscillations that might be created between a primordial black hole and the sun, the masses of a primordial black hole and the likely path of the object through the sun. Meanwhile, NASA’s Tim Sandstrom used the Pleiades supercomputer at the NASA Ames Research Center in California to provide video simulations of their calculations.

Hanasoge and Kesden said they hope to find information about other stars from existing NASA telescopes that are examining extrasolar planets, but that big questions remain about the feasibility of scale up the sample size.

“The bottom line is, no one knows what dark matter is and so everything should be considered,” physics professor Frans Pretorius said, adding that future research on the subject will depend on whether the scientific community finds a different source for dark matter.

The report was published in the September issue of Physical Review Letters.