Summary

As Randall and her associate Matthew Reece focus on the effect of dark matter on ordinary matter, their work becomes intensified. Randall defines the exact purpose of their mission:

"The idea was that dark matter could effectively sling comets out of the Oort Cloud so that they periodically catapulted into earth, possibly even precipitating a mass extinction."

At first blush, that notion seemed far-fetched but they decided to proceed because Randall had inadvertently asked Reece about meteoroid impacts on the same day that the Chelyabinsk meteoroid crashed into earth. They wondered why dark matter affected earth in the form of meteoroids in a 30 to 35 million year cycle. Their work would test the idea whether a 15-kilometer-wide asteroid smashed into the earth 66 million years ago, triggered by the gravitational force of a dark matter disk near the center of...