It's been known for a while that there was a catastrophic asteroid collision millions of years ago while dinosaurs roamed the Earth. It was definitely about 9-miles wide, and definitely hurtled into Chicxulub, Mexico, leaving a 110-mile crater. Likewise, it definitely caused an explosion two million times bigger than the biggest thermonuclear device ever, launching an epic dust cloud that blocked out the sun. But—but but but—according to previous evidence, all that could have happened as early as 300,000 years before the actual extinction of dinosaurs, meaning there might have been different/additional cause.
Turns out probably not. Go figure, but that catastrophic impact was enough to do the trick, according to a new paper published in Science. Scientists from Europe and the US have been able to look at the crater's dust and narrow the impact down to a mere 11,000 year window, which is incredibly small in geological terms. As it happens, the impact was practically simultaneous with the mass extinction. Sure, Earth hadn't been at its strongest immediately before impact, but it was definitely the asteroid that kicked off all the dying.
So that's that. Mystery (re)solved, and lucky for us, the story hasn't changed. Good thing too; it's such a good one. More here.