Two detected gravitational waves hint at the presence of ancient black holes in space.
Key Takeaways
- Dark matter might consist of primordial black holes formed right after the Big Bang.
- Gravitational wave data suggests two detected events could involve these ancient black holes.
- Primordial black holes may explain the unseen dark matter halos around galaxies.
- The study links black hole masses to their possible origins, including neutron star transformations.
- Future gravitational wave discoveries will improve this test to confirm dark matter’s nature.
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Are Black Holes the Key to Dark Matter?
A new study proposes that dark matter, the mysterious substance that exerts gravity without emitting light, could be made of primordial black holes formed during the universe’s earliest moments. Researchers analyzed gravitational waves produced by two cosmic collisions — GW190425 and GW190814 — detected in 2019 by LIGO in the U.S. and Virgo in Italy. These ripples in spacetime suggest the presence of “solar-mass black holes,” whose origins defy conventional astrophysics.
Unlike typical black holes formed by collapsing massive stars, solar-mass black holes are theorized to be “primordial” black holes. These ancient objects may have originated within the first second after the Big Bang, ranging in size from microscopic to massive clusters tens of thousands of times the Sun’s mass. Over time, smaller primordial black holes would have evaporated through Hawking radiation, leaving only those above 10^11 kilograms — approximately the mass of a small asteroid.
If primordial black holes exist, they could account for the immense halos of dark matter enveloping galaxies, solving one of astrophysics’ greatest mysteries.
Unraveling the Mystery of Primordial Black Holes
The researchers also explored how neutron stars — dense remnants of supernovas — might transform into black holes by interacting with dark matter. When neutron stars attract dark matter particles, the combined mass could become so dense that the star collapses into a black hole. Another possibility is that a neutron star merges with a tiny primordial black hole, which then consumes the star from within until only the black hole remains.
Gravitational waves from cosmic collisions provide essential clues. Takhistov and his team examined over 50 gravitational wave detections and found two events, GW190425 and GW190814, that likely involved black holes matching the mass distribution of neutron stars. This challenges existing theories since black holes formed from neutron stars should align closely with known stellar masses. The researchers argue that these anomalies may point to primordial black holes as a plausible explanation.
While this evidence isn’t conclusive, the study published in Physical Review Letters opens a new avenue for testing the relationship between black holes and dark matter. The statistical nature of the analysis requires more gravitational wave detections to strengthen these findings, but early results suggest that primordial black holes could be significant contributors to dark matter.
As gravitational wave detectors become more sensitive, the ability to identify these ancient black holes will improve. Such discoveries could finally unveil the true nature of dark matter and its connection to the universe’s origins.
