Historian and scientific researcher Kenneth J. Dillon explains his The Martian Theory of Mass Extinctions. For most of the past 4 billion years, the orbits of Mars and Earth were more eccentric than at present, and they intersected. The closest approaches of Mars led to the great mass extinctions of prehistory, while more distant approaches might account for many minor extinctions as well. The theory shows why the extinctions were serial events, why they differed in size, how they shaped the surface of Mars, and what made them so terrifically devastating. For further information, see https://www.scientiapress.com/extinctions.