Rockin’ since 1969
In 1969, Randy Korotev was a sophomore at the University of Wisconsin majoring, tentatively, in chemistry. After pursuing an interest in geochemistry sparked by flipping through the back pages of his chemistry book, Korotev landed in a lab working under a professor who studied lunar rocks—more specifically, lunar rocks brought back from the Apollo 11 mission.
Now, after 40 years, Korotev is a research faculty member in the Washington University earth and planetary sciences department. While the times have changed significantly since the 1960s era, Korotev’s research material has not.
“Sometimes people ask me, ‘How can you still be studying these samples 40 years later—haven’t you learned everything there is to know?’” Korotev said, laughing as he shook his head no. “I remind them that terrestrial geologists have been studying the earth for at least two hundred years and they haven’t figured it out yet.”
According to Korotev, scientists still do not know the answers to many of the big questions concerning the moon’s formation, which may give crucial clues to the history of the solar system.
“We believe the moon had what people call a ‘magma ocean,’ that when it did form it was mostly molten. The earth may have started out that way too,” he said. “But the real issue is the moon as a recorder of things that happened in the early solar system.”
Unlike the earth, the moon has no plate tectonics, wind or water. The only remaining evidence of its history is the numerous craters, or basins, left from meteoroid impacts on the surface. Now, scientists are most interested in examining the rate of impact in relation to time.
“We think we can figure that out from the moon, but 40 years later we’re still arguing about certain aspects of that,” Korotev said.
Because all the lunar rocks are precious and few, researchers like Korotev have learned to experiment and work with scaled-down samples sliced into multiple pieces by diamond cutters.
All the rock samples collected from the large basins during the Apollo missions can be dated to about 3.9 billion years ago. One popular hypothesis among geochemists is that the basins formed during a great catastrophe in the solar system around that time.
A large crater sits on the far side of the moon called the South Pole-Aitken basin. Scientists can tell the South Pole-Aitken basin in the back side is older than any others on the front, since they can observe in it ejecta, debris ejected during an impact crater’s formation, originating from the front-side craters.
“If we can go and get impact melt rock that was formed when that basin was formed, and if it was 3.9 billion years old—simple experiment—it proves a cataclysm. It proves that everything happened at once,” Korotev said.
Plans are the in works for a lunar mission to collect samples from the South Pole-Aitken basin sometime within the next 10 years, he said.
Aside from studying the Apollo 11 samples, Korotev also spends much of his time analyzing lunar meteorites retrieved from the Middle East, Australia, Africa and Antarctica.
One of the first lunar meteorites was found in Antarctica by accident when a Japanese glaciology team spotted nine pieces of rock from different meteorites on a slab of bare ice in the mid-1970s.
Starting in 1976, teams from the United States and Japan went on regular expeditions in search of lunar meteorites.
“At the time the Antarctica meteorite program started, there were less than 3,000 known meteorites in all of the ends of the world. I think they found over 30,000 [since then],” Korotev said.
Sitting in his office, Korotev is surrounded by photos of the lunar landscape and rocks on the wall, as well as various rock samples on his bookshelves—some lunar, some not.
Private collectors and meteorite hunters from around the world send Korotev pictures of the rocks they find or the rocks themselves to ask for his opinion. Most of the time, these rocks turn out to be ordinary rocks from earth.
To sort out the lunar meteorites from the “fake,” terrestrial ones he receives, Korotev has set aside two cardboard boxes labeled “METEORWRONGS.” Both are heavy and full.
There has been a rising trend in private meteorite hunters in the past few years, allowing samples to be easily bought or sold in the online market.
“I buy these things off of eBay,” Korotev said. “The prices are down too. You buy by the mass, for the most part, like $1,000 a gram.”
The process has become so commercialized that four men have contacted Korotev recently to ask whether they can buy his samples to put them into engagement rings.
But Korotev is holding on to his valuable lunar meteorites for study.
He sends his interested buyers away with the advice, “You know, they’re kind of ugly, and the moon has never seen any water. Why don’t you get her a diamond?”