Electromagnetic Signatures From Primordial Black Holes in the Solar System

Primordial black holes in the asteroid-mass range, with typical masses $10^{17}\, {\rm g}\lesssim M \lesssim 10^{23}\, {\rm g}$, have drawn significant recent attention as a viable dark matter candidate. The new analysis still awaits peer review, but it already lays out the central claim clearly.

That matters because cosmology operates at the edge of what current instruments can measure, where systematic errors and model assumptions are never trivial. Small discrepancies between independent measurements have historically pointed toward missing physics rather than simple calibration errors, and the ongoing tension in the Hubble constant is a live example of how a persistent disagreement between methods can reshape the theoretical landscape. Each new dataset that approaches this territory with independent systematics adds real information to a problem that has resisted easy resolution for more than a decade. The peak frequencies of photons emitted via Hawking radiation from asteroid-mass PBHs range from infrared to $γ$-ray bands. We calculate expected local transit rates for extended PBH mass distributions which could comprise all the dark matter.

We evaluate prospects for detecting Hawking-radiated photons from local PBH transits through the inner Solar System and from PBH explosions in the far outer edges of the Solar. We consider several existing and proposed ground-based and space-based instruments sensitive to photons from the radio band to ultrahigh energy $γ$-rays.

We find that proposed instruments, such as the AMEGO-X satellite, could reliably detect PBH transits within ${\it O} (0. We conclude by specifically considering potential companion electromagnetic signatures in the case of a PBH explosion about $10^3\, {\rm AU}$ from Earth, which has been suggested.

The relevance goes beyond one dataset because even small shifts in measured parameters can matter when the field is testing the limits of the standard cosmological model. The Lambda-CDM framework describes the observable universe with remarkable economy, but its success rests on two components, dark matter and dark energy, whose physical nature remains entirely unknown. Any credible measurement that tightens or loosens the constraints on those components moves the entire theoretical enterprise forward, regardless of whether the immediate result looks dramatic on its own terms.

Because this is still a preprint, the result should be read with genuine interest and proportionate caution. Peer review is not a guarantee of correctness, but it is a process that forces authors to respond to technical criticism from specialists who have no stake in a particular outcome. Preprints that survive that process, often with substantive revisions, emerge with a stronger evidential base than the version that first appeared. Until that stage is complete, the responsible reading keeps uncertainty explicitly visible rather than treating the claims as established findings.

The next step is to see whether the effect survives when independent surveys, different calibration strategies and tighter control of systematic uncertainties enter the picture. Programmes such as Euclid, DESI and the Rubin Observatory will deliver datasets over the next several years that cover the same parameter space with largely independent methods. If the current signal persists through those tests, its theoretical implications will become impossible to set aside. Until peer review and independent follow-up address those open questions, skepticism is not a failure of appreciation for the work; it is part of how science decides what to keep.

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