According to a story in Foxnews:
The sun bounces up and down as it roams the Milky Way, and such wavering might have hurled showers of comets Earth's way that caused mass extinctions, including the one that killed the dinosaurs, a new study claims.
Not everyone is convinced:
"The whole concept is wrong," said NASA Jet Propulsion Laboratory astronomer Paul Weissman, who did not participate in this study. "As you cross the galactic plane, it's not like you go over a speed bump. The variation in any cratering rate would be very gentle, not in sudden pulses."
This ought to be fun to watch.