Have we finally solved mystery of magnetic moon rocks?

NASA's Apollo missions brought back moon rock samples for scientists to study. We've learned a great deal over the ensuing decades, but one enduring mystery remains. Many of those lunar samples show signs of exposure to strong magnetic fields comparable to Earth's, yet the Moon doesn't have such a field today. So, how did the moon rocks get their magnetism?

There have been many attempts to explain this anomaly. The latest comes from MIT scientists, who argue in a new paper published in...