Charges on strange quark nuggets in space

Since Witten's seminal 1984 paper on the subject, searches for evidence of strange quark nuggets (SQNs) have proven unsuccessful. In the absence of experimental evidence ruling out SQNs, the validity of theories introducing mechanisms that increase their stability should continue to be tested. To stimulate electromagnetic SQN searches, particularly space searches, we estimate the net charge that would develop on a SQN in space exposed to various radiation baths (and showers) capable of liberating the SQN's less strongly bound electrons, taking into account recombination with ambient electrons. We consider, in particular, the cosmic microwave background, radiation from the sun, and diffuse galactic and extragalactic ultraviolet backgrounds. The largest charge, for the settings considered, develops on a solar system SQN exposed to a solar X-ray flare. A possible dramatic signal of SQNs in explosive astrophysical events is noted.