The South Pole-Aitken basin shows up clearly as low-lying blue in a topographical map of the moon, with the newly discovered mass located underneath the dotted line. (Credit: NASA/Goddard Space Flight Center/University of Arizona)

Buried under the largest, oldest crater on the moon,
scientists have discovered an enormous mass of dense material, possibly the
remains of the asteroid that formed the crater some 4 billion years ago.

Astronomers led by Peter B. James from Baylor University di