The universe is full of invisible mass — dark matter. One hypothesis: it's made of tiny black holes born in the Big Bang. With the mass of an asteroid and smaller than an atom, they slip through planets unnoticed. Stephen Hawking back in the 1970s suggested such holes could explode, but they've never been seen.
Now astronomers have figured out how to track them down. Flying past a pulsar, a cosmic lighthouse with a perfectly steady rhythm of radio pulses, such a hole would gravitationally disturb its 'ticking'. A network of gravitational wave detectors would pick up this glitch. The second trail: a collision with an icy body beyond Neptune's orbit. The impact would heat gas to a glow, flashing for a split second brighter than the full Moon, like a signal bonfire.
These methods for the first time allow us to catch dark matter right in the Solar System, turning an invisible phantom into prey.
as written by the authors arXiv:2511.04895
Primordial Black Holes (PBHs) represent one of the more interesting ways to address dark matter, at the interface of both cosmology and quantum gravity. It is no surprise then that testing PBHs is a venue of active interest, with several cosmological and astrophysical probes constraining different mass ranges. In this work, we propose novel Solar System scale searches for PBHs, motivated by the unique precision and coverage of local observables. We show that asteroid to dwarf planet mass PBHs can induce measurable dipolar timing signatures in pulsar timing arrays, while planetary mass PBHs can generate detectable ADAF accretion flares through interactions with Kuiper Belt bodies. Together, these complementary approaches open a new observational frontier for probing PBHs across mass ranges that remain unconstrained by conventional cosmological methods.
A black hole with the mass of an asteroid is compressed to smaller than an atomic nucleus: it would pierce through Earth without touching a single atom.
In Larry Niven's story 'The Hole Man', a microscopic black hole falls on Mars — much like in the real hunt for hidden things.