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Yesterday, July 20, marked the 40-year anniversary of the first mission to land astronauts on the moon. To commemorate the event, NASA released newly restored footage of the Apollo 11 moonwalk, which an estimated 500 million viewers watched broadcast live on TV.

Wired  Randy Korotev, a Washington University lunar geochemist, about scientists learned from the roughly 50 pounds of rock and soil the astronauts collected:

“We learned so much, just from that first mission. There was some first-order stuff that we didn’t understand. We had never seen stuff like this lunar soil that had been exposed directly to space for billions of years. The soil and some of the aspects of it were completely unknown,” he said. “We learned how old these basaltic dark spots were. It turned out they were 3 billion years old. It’s hard to find a rock on Earth that old, and when you look at them, it’s like they happened yesterday.”

“We learned about how the solar wind implanted ions into the soil from the sun,” he continued. “That’s the kind of stuff we never have on Earth, because the solar wind is absorbed by the atmosphere. People could study the cosmic ray tracks left when a cosmic ray hits a mineral grain. You can count the cosmic interactions in a cubic millimeter — and they are coming from outside the solar system. The list of things we learned is endless. It’s so endless that I can’t even begin to give everybody’s fields justice.”