The serpent’s tails coil together menacingly. A horn juts
sharply from its head. The creature looks as if it might be
swimming through a sea of stars. Or is it making its way up a
sheer basalt cliff? For Bruce Masse, an environmental
archaeologist at Los Alamos National Laboratory, there is no
confusion as he looks at this ancient petroglyph, scratched into
a rock by a Native American shaman. “You can’t tell me that
isn’t a comet,” he says. In Masse’s interpretation, the
petroglyph commemorates a comet that streaked across the sky
just a few years before Europeans came to this area of New
Mexico. But that event is a minor blip compared to what he is
really after. Masse believes that he has uncovered evidence that
a gigantic comet crashed into the Indian Ocean several thousand
years ago and nearly wiped out all life on the planet. What’s
more, he thinks that clues about the catastrophe are hiding in
plain sight, embedded in the creation stories of cultural groups
around the world. His hypothesis depends on a m