New Gravitational-Wave Signal May Reveal Primordial Black Holes Born After the Big Bang

The Big Bang may have been the first to give scientists a clue of the existence of primordial black holes. The hint was a strange gravitational-wave signal which was recorded in November 2025 by the LIGO–Virgo–KAGRA observatories. This signal can be caused by the collision of two small black holes (which may not be bigger than a coin). In case it is real, astronomers explain that it would be a discovery of the first in terms of exotic remnants of the early universe.

Unusual gravitational-wave signal

According to reports, LIGO–Virgo–KAGRA detectors flagged an unusual gravitational-wave signal in November 2025 (event S251112cm). The data showed one merging object had a mass far below any known stellar remnant. Durham University physicist Djuna Croon said the finding would be “enormous” if confirmed, since standard astrophysics cannot explain it. The LIGO team cautions this could still be a rare noise glitch (false-alarm odds roughly 1 in 4 years). But even a small chance of a true signal is thrilling, because primordial black holes have long been theorised but never confirmed.

Primordial black holes: cosmic relics

The primordial black holes are theoretical entities which were formed during the very early epochs of the Big Bang, as opposed to the black holes of collapsing stars. They might have masses which are wildly different - less than a paper-clip to 100,000 Suns. In case they do, they could constitute dark matter, an invisible matter that constitutes the 85 percent of cosmic mass. These black holes would not require any exotic particle (they would fit in the known physics). None of them has so far been discovered; very light ones would have evaporated long ago.