Jul 23, 2013

Self portrait from outer space

NASA continues to send back astounding pictures from its explorer spacecraft.

On the same Earth day, July 19, 2013 two of these - Cassini-Huygens orbiting Saturn, and MESSENGER orbiting Mercury, captured these views of the Earth and Moon.

Two views of home (ID: PIA17038; NASA/JPL-Caltech/Space Science Institute and NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)
Here are close ups from the above image:

Saturn's view: 1.44 billion kilometers (898 million miles) away. "Earth appears as a blue dot at center right; the moon can be seen as a fainter protrusion off its right side." - NASA

Mercury's view: 98 million kilometers (61 million miles) away. "Earth and the moon appear very large in this picture because they are overexposed. When looking for potentially dim satellites, long exposures are required to capture as much light as possible." - NASA

While Cassini's main mission is to study Saturn system, including its spectacular rings and moons, it has captured - "only the third time ever that our planet has been imaged from the outer solar system" (NASA). The Earth image was taken as part of a wider mosaic of images of the entire Saturn system. Looking back at Earth from Saturn can be difficult as the bright sun is in the same direction, but Cassini placed itself in the shadow of Saturn. From its position experiencing a solar eclipse and capturing the less bright objects around the area.

"This simulated view from NASA's Cassini spacecraft shows the positions of Saturn and Earth on July 19, 2013" - NASA/JPL-Caltech
The deliberately inserted narrow-angle frame images in the sequence shot from Cassini shows a clearer separation of the Earth and the moon.

Narrow-angle frame image, with a 5 times magnification view (ID: PIA14949 & PIA17170, NASA/JPL-Caltech/Space Science Institute)
In every story told and lived, our anthropocentric mind prefers to get involved when we are part of the story. For all the work that NASA and other space programs are doing, the most evocative tend to be these images, looking back at us from almost untouchable distances.

At a point like this we always come back to Carl Sagan's words:
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there-on a mote of dust suspended in a sunbeam.
In his time he was referring to this earlier picture:

Taken by Voyager 1 in 1996, from a distance of more than 6.4 billion km (4 billion miles) from Earth. (NASA/JPL ID:PIA00452)

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