BBC:
Ancient Egyptians used mud bricks to build houses, tombs, and
temples. Because the bricks are denser than sand, the thermal
signatures of the two materials are different. As the BBC's
Frances Cronin reports, Egyptologist Sarah Parcak of the
University of Alabama at Birmingham exploits those differences
to hunt for ancient cities that have been hidden for millennia
beneath meters of accumulated sand. The locations of the cities
show up in high-resolution IR images taken by satellites. By
examining the images, Parcak and her collaborators have found
3000 settlements, 1000 tombs, and 17 pyramids—all
previously unknown to archaeologists.
