Researchers have discovered a 4.6 billion-year-old meteorite rock in the Sahara Desert, that they say once belonged to a long-lost baby planet that never made it to adulthood. The meteorite may be the oldest rock ever analyzed, scientists wrote in a study published in the journal Proceedings of the National Academy of Science, and perhaps one of the few remaining pieces of evidence of the solar system’s planetary ancestors. “I have been working...