An unassuming rock collected from the surface of the moon over 50 years ago by the Apollo 17 astronauts Gene Cernan and Harrison Schmitt could completely alter what we thought we knew about the early days of the moon and, by extension, the solar system.
The rock sample, catalogued simply as 76535, has a chemistry and texture that indicates it formed deep down in the moon's crust, nearly 31 miles ( 50 kilometers) underground. Moreover, radioisotope dating places it as having been on the lunar surface for 4.25 billion years.
