A NASA spacecraft designed to look for comets turned its cameras homeward, capturing a unique view of the moon passing in front of the Earth as seen from 31 million miles away. The spacecraft, Deep Impact, took shots at 15-minute intervals, which were combined to make the sequence shown below.
The latest images show the moon and Earth in greater detail than previous ones taken by orbiting spacecraft, showing oceans and continents on our planet and craters on the moon. By studying how Earth looks from so far away, the scientists hope to sharpen their search for alien worlds that may share similar characteristics.
Sara Seager, a planetary theorist at the Massachusetts Institute of Technology and a co-investigator on the extended mission for Deep Impact, notes that the data being gathered are just for planning purposes because the discovery of a good candidate alien planet is a long way off in the future.
But should that time come, by comparing this detailed image of Earth to a glimmering, flickering point source of light, “we want to be able to infer whether there are oceans and continents on another planet,” she said. — SARAH GRAHAM