Dinosaurs might still be roaming the Earth today if not for an incredible run of bad luck 66 million years ago. Researchers had already determined that the city-sized asteroid that hit the planet, leading to the mass extinction, struck at the exact wrong place at the exact wrong time. Scientists now believe it slammed into what is now Mexico at the worst possible angle as well. In a study published Tuesday in the journal Nature, researchers say they have determined that the Chicxulub crater was formed by an asteroid hitting steeply inclined, 45 to 60-degree angle from the northeast, causing maximum damage and sending a huge amount of climate-changing gases into the atmosphere.
Lead author Gareth Collins, a professor of planetary science at Imperial College London, says the asteroid's "nuclear winter" effect, which killed off around 75% of the Earth's species, was "likely worsened by the fact that it struck at one of the deadliest possible angles," CNN reports. He says the team's simulations have shown that if the asteroid had hit from straight overhead, it would have sent less vapor into the atmosphere—and less rock would have been vaporized if it had struck more of a glancing blow. "It’s sort of a perfect storm," Collins says, per the New Scientist. "This was a very bad day for the dinosaurs, and the more special the circumstances that had to come together to cause this event, the less likely that it’ll happen again." (In North Dakota, researchers found "the death blow preserved.")