Gamma-ray burst linked to mass extinction I just came across this little article which discusses the possibility that the late Ordovician mass extinction* may have been caused by a gamma-ray burst. Gamma-ray bursts are very short but astoundingly intense flashes of gamma radiation which might be associated with events such as supernovae. Their exact cause is unknown, but having one occur in your galaxy is probably going to ruin your day. First they fry you, then they cause an ice age. Thankfully, they seem to be very rare. This article, cited in the references, is short and pretty easy to follow. Zzzzzzzzzzzzap *The late Ordovician mass extinction, from what I've read, may in fact consist of two events separated by as much as 2 million years. I'm making the assumption that the proposed GRB is associated with the earlier event.