Wired reports about recent meteorite and asteroid impact studies:
A meteorite the size of Mt. Everest plummeted into the Earth with such force nearly 2 billion years ago that it caused part of the Earth's crust to flip inside out, according to Canadian researchers...
Though catastrophic meteorite impacts on Earth are few and far between, scientists are concerned that such a strike in the future could have a dramatic effect on the human race. Last month, a team of American scientists released a report claiming that most land-living dinosaurs were incinerated within hours after an asteroid impact at Chicxulub, Mexico, nearly 45 million years ago. And a few weeks before that report, a different team linked a meteorite to the Great Dying, a mass extinction on Earth that took place approximately 250 million years ago.
A Galactic Wrecking Ball [Wired]