Measuring Black Holes with Spacecraft Stopwatches ⚡ экспресс
Evaporating primordial black holes (PBHs) could give themselves away with gamma-ray bursts that have a curved wavefront. To tell them apart from distant explosions, the authors used a geometric method: by comparing arrival times of gamma rays at different satellites and the burst's coordinates, they calculate the distance. Analysis of Swift data showed no deviations from a flat wave; the tightest constraint is 1.2 AU (almost to Mars). Already, the method can 'reach' up to 1000 AU, and future detectors up to 100,000 AU, which would directly determine the mass and lifetime of a PBH.
A pebble dropped in a pond creates curved ripples, but from far away they appear as straight lines. Gamma-ray flashes from an evaporating black hole behave the same: a distant burst sends flat waves, while a nearby one arrives curved.
Astronomers use this curvature to measure distance. By comparing the tiny time lags between satellites (because the speed of light is constant), they can pinpoint the source. This technique, using light measurement (photometry), has been checked with NASA's Swift satellite. No curved signals appeared within 1.2 AU — the Earth-Sun gap. But future deep-space probes could search farther. The prey are primordial black holes: relics from the Big Bang, smaller than an atom yet heavier than a skyscraper. If one evaporates, it would emit a Hawking radiation burst we could catch.
🎯 Primordial black holes, if they exist, are tiny but incredibly dense — remnants from the Big Bang — and they could be evaporating today, flashing gamma rays detectable by deep-space probes.