When Apollo astronauts returned from the Moon, they brought with them samples from the lunar surface for analysis. but these samples contained something quite mysterious: organic matter in the form of amino acids.

They certainly didn’t come from the moon; it’s completely inhospitable to life. So where did they come from? Were they contamination from terrestrial sources, rocket exhaust from the lunar modules, solar wind, or asteroids and meteorites?

“People knew amino acids were in the lunar samples, but they didn’t know where they came from,” said Jamie Elsila of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The scientists in the 1970s knew the right questions to ask and they tried pretty hard to answer them, but they were limited by the analytical capabilities of the time. We have the technology now.”

What exactly did our scientific sleuths find? Read the full report now.

Image Above: Astronaut Alan L. Bean, Lunar Module pilot for the Apollo 12 lunar landing mission, holds a container filled with lunar soil collected while exploring the lunar surface. Astronaut Charles “Pete” Conrad Jr., commander, who took this picture, is reflected in the helmet visor. Credit: NASA