A better way of searching for black-hole explosions?

Abstract

BLACK holes of ≲ 10¹⁵ g evaporate in ∼ 10¹⁰ yr, and eventually annihiliate into a burst of energetic photons and particles¹. To test this theoretical prediction would be extraordinarily significant for quantum and gravitational physics. There could be ∼ 10²³ ‘miniholes’ within our Galaxy^2–4; on the other hand, there may not be any at all. But even if they exist in profusion, how best could we detect black-hole explosions? Attention has been focused on the problem of directly detecting the γ rays, but the prospects seem bleak³. The possibility that the particles ejected in the explosion may generate conspicuous effects has hitherto been overlooked. I argue here that collective interaction of electrons and positrons with an ambient interstellar magnetic field can (on some specific assumptions) generate radio bursts powerful enough to be detected from anywhere in our Galaxy, or even beyond. This opens up a more promising perspective on the search.