Tiny 40‑ton black holes could hide inside stars, new theory suggests

A fresh theoretical analysis proposes that black holes with a mass comparable to a large cargo ship—about 40 tons—might be able to form deep within ordinary stars if sufficient dark matter gathers at their cores.

The idea builds on Stephen Hawking's 1974 insight that black holes are not completely black but emit a faint quantum glow now called Hawking radiation. That emission causes the smallest black holes to evaporate rapidly, meaning a micro‑black hole would normally vanish in a fraction of a second.

At 40 tons, such an object would be billions of times lighter than the stellar‑mass black holes produced by collapsing massive stars. Its tiny horizon would make it vulnerable to rapid evaporation, unless an external energy source could feed it.

Researchers suggest that dense clumps of dark matter—particles that interact only weakly with ordinary matter—could drift toward a star’s center over millions of years. If enough of these particles accumulate, their collective gravity might trigger a collapse into a microscopic black hole. The surrounding dark matter could then continue to supply mass, slowing the evaporation process long enough for the black hole to persist inside the star.

Such a scenario, if real, would offer a novel window into the elusive nature of dark matter. The presence of an embedded micro‑black hole could subtly alter a star’s energy transport, potentially producing atypical neutrino or gamma‑ray signatures that astronomers might one day detect.

The proposal remains speculative, and scientists emphasize the need for detailed simulations and observational strategies to test it. Future high‑sensitivity neutrino detectors and space‑based gamma‑ray observatories could, in principle, search for the faint signals that a dark‑matter‑fed black hole would generate, providing a unique test of both black‑hole physics and dark‑matter models.