A slice of NWA 12774.The green circle is an olivine crystal, a magnesium-rich mineral. (Credit: John Kashuba) In A Nutshell A meteorite recovered from the Sahara contains crystals that could only have formed deep inside a large, now-destroyed ancient planet, giving scientists their first direct physical evidence of its enormous size. Using a newly developed pressure-measuring tool, researchers calculated the parent body was at least 1,000 kilometers in radius, far larger than any asteroid previously linked to this class of meteorite. Textural clues in the crystals suggest the planet may have been Moon-sized or even larger, though that conclusion depends...