Until now, all of the quarry's fossil meteorites were L-chondrites. Schmitz, who has led the chondrite cataloging, admitted the rock hunt had become "quite boring."

But the rare find has not only revitalized interest in the quarry, it has also brought together the world's top meteorite experts for a global hunt through geologic time. Thanks to Schmitz's careful detective work on meteorites, scientists now know that each kind of meteorite leaves behind a unique calling card: tough minerals called spinels. Even if meteorites weather away, their spinels linger for hundreds of million of years in Earth rocks. Schmitz and his cohorts think they can pin down how many meteorites rained down on Earth in the past 2.5 billion years, as well as what kind fell, by extracting extraterrestrial spinels from sedimentary rocks. Their work may confirm suspicions that recent meteorite falls represent a mere fraction of the rocks drifting in space.

"I think our new finding adds to the understanding that the meteorites that come down on Earth today may not be entirely representative of what is out there," Schmitz said. "One thing our study shows is that we maybe don't know as much as we think we know about the solar system."

The limestone quarry preserves the remnants of a cosmic cataclysm that took place 470 million years ago, during the Ordovician Period. Scientists think there was an enormous crash between two large bodies out in the asteroid belt. The crash blew apart two asteroids, or an asteroid and comet, slinging dust and debris toward Earth. One of the impactors was the source of all L-chondrite meteorites. But no one has ever found a piece of the rock that hit the L-chondrite parent, until now.

The Swedish meteorite's exposure age — the length of time it sailed through space — is the key to placing the fossil space rock at the scene of the crash. The meteorite zipped from the asteroid belt to Earth in just 1 million years. That's the same remarkably young exposure age as the L-chondrites recovered from the Thorsberg quarry, suggesting the rocks sprayed Earth in the same wave of space debris.

Meteorite expert Tim Swindle, who was not involved in the study, praised the team's careful analysis and said it was unlikely that any other meteorite but an Ordovician fragment would have such a short exposure age. "Very, very few modern meteorites have exposure ages that low," said Swindle, a professor at the University of Arizona in Tucson. "Typically, it takes things longer to get here from the asteroid belt," he said. "It's a telling argument."