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NASA's Cassini probe to picture Earth from almost a billion miles away
On July 19 this year, NASA's Cassini spacecraft will capture an image of Earth seen from nearly a billion miles away, glimpsed beside Saturn's rings.
Ever since the Apollo astronauts captured the first "Earthrise" photograph in 1968, showing our planet seen from near the surface of the moon, the world has been fascinated by images of Earth, taken from space.
On July 19 this year, NASA's Cassini spacecraft will capture one of the most spectacular yet - Earth seen from nearly a billion miles away, glimpsed beside Saturn's rings during an eclipse of the sun.
It will be the first time that Earthlings know in advance that the Cassini probe is to take their picture - the spacecraft has imaged Earth before in 2006, with our planet appearing as a tiny dot next to Saturn's rings.
“It will be a day,” says Cassini imaging team leader Carolyn Porco of the Space Science Institute in Boulder, Colorado, “for all the world to celebrate.”
[Related: Earth - seen from the Space Station]
“Ever since we caught sight of the Earth among the rings of Saturn in September 2006 in a mosaic that has become one of Cassini’s most beloved images, I have wanted to do it all over again, only better,” said Porco.
Porco was involved in the famous “Pale Blue Dot” image of Earth taken by NASA’s Voyager 1 from beyond the orbit of Neptune in 1990.
“While Earth will be only about a pixel in size from Cassini’s vantage point 898 million miles away, the Cassini team is looking forward to giving the world a chance to see what their home looks like from Saturn,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
Like Cassini's previous images of Saturn and its rings, the image will be a mosaic, using camera filters -- red, green and blue -- that can be composited to form a natural color view, or what human eyes might see at Saturn.
Imaging any planetary body close to the Sun requires that the Sun is completely blocked, so that no undiluted sunlight can enter the cameras or other Cassini instruments and damage their sensitive detectors. Such opportunities are rare.
The team found that Cassini would be in Saturn's shadow for several hours on July 19 - and chose that time to capture the image.
“My sincere wish is that people the world over stop what they’re doing at the time the Earth picture is taken to revel in the sheer wonder of simply being alive on a pale blue dot of a planet, and to appreciate the ever-widening perspective of ourselves and our world that we have gained from our interplanetary explorations," says Porco.
