| If a large meteorite slammed into the earth, it would turn rock into dust. Dust from the crust and from the meteorite would be injected into the atmosphere and circulate around the world. |
| The dust could have the effect of turning day into night on Earth for years. Plants, including the microscopic plants in the ocean, would stop manufacturing food. This could have caused the mass extinctions. |
Barringer Meteor Crater, Arizona. Courtesy of Calvin Hamilton, D. Roddy and LPI.