An alien’s-eye view of Earth and Moon

Nasa Movie Shows World From 50M Km Away

Washington: A spacecraft sent on a mission to inspect comets has filmed the Earth and its Moon from 50 million kilometres away, making an alien’s-eye view of our world.

The two brief sequences show the Moon passing in front of the Earth as it orbits. “Making a video of Earth from so far away helps the search for other life-bearing planets in the universe by giving insights into how a distant, Earth-like alien world would appear to us,” said University of Maryland astronomer Michael A’Hearn, who leads the project using Nasa’s Deep Impact spacecraft.

“Our video shows some specific features that are important for observations of Earthlike planets orbiting other stars,” added Drake Deming of Nasa’s Goddard Space Flight Center in Greenbelt, Maryland.

“A ‘sun glint’ can be seen in the movie, caused by light reflected from Earth’s oceans, and similar glints to be observed from extrasolar planets could indicate alien oceans,’ Deming added.

“Also, we used infrared light instead of the normal red light to make the color composite images, and that makes the land masses much more visible.”

That’s because plants and some microbes reflect near-infrared light — apparently because absorbing it would cause them to overheat during photosynthesis — and that causes land masses to appear bright at these wavelengths.

“To image Earth in a similar fashion, an alien civilization would need technology far beyond what Earthlings can even dream of building,” added Sara Seager, a planetary theorist at the Massachusetts Institute of Technology in Cambridge. REUTERS

AN OUT-OF-THE-WORLD VIEW: A still from a video sequence of the Moon passing in front of the Earth, shot by Nasa’s Deep Impact satellite.