Sharma says that the key will be to find the crater. Although he has no experience in crater-hunting, he is now putting together a proposal. But Mark Boslough, an impact physicist from Sandia National Laboratories in Albuquerque, New Mexico, thinks that a find is unlikely. If there had been an impact, “there’d be a great big obvious crater”, he says. “We wouldn’t have to argue about it.”
Steven Stanley, a paleobiologist from the University of Hawaii at Manoa in Honolulu, has acted as a ‘personal editor’ on several of the PNAS papers on this topic, including the new work by Sharma and the original 2007 paper proposing the idea. “It has been very controversial,” he admits. “It’s my view that I should help to get this stuff published. It needs to be aired; it’s not outlandish.” PNAS typically uses a 'personal editor' option for papers considered too controversial to receive a fair hearing from the standard review process.
Stanley says he is increasingly convinced by the impact theory as a mechanism for what prompted the freshwater floods. “I’m not sure how people can be so negative at this point. The case just builds.”