In doing so she has sparked a scientific civil war.
And all because she questioned the accepted theory about what wiped out the dinosaurs.
Scientists began to investigate a layer of rock formed sixty five million years ago.
It's seen in mines and rock outcrops around the world.
Below this layer there are lots of dinosaur fossils, above it there are none. It's called the KT boundary.
This is the KT boundary, and because it's such a thin, sharp line
we know something dramatic must have happened here, some catastrophe
and until recently we have almost no clue what happened whatsoever here, so it remained a total mystery.
Then in 1979 they discovered a clue in the KT boundary.
A high concentration of an element called Iridium.
Such quantities are extremely rare on earth and usually come from outer space.
So as soon as you find ten thousand times more Iridium at the very moment when the dinosaurs disappear,
you know somewhere on earth a very big impact must have happened by an asteroid or a comet.