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| Space on Jul 19, 2014

This date in science: The day Earth smiled

On July 19, 2013, the Cassini spacecraft acquired a distant image of our home world, as we Earth citizens cast our thoughts spaceward.

July 19, 2013. On this date last year, humanity acquired its third-ever image of Earth from the outer solar system, as the planet Saturn eclipsed the sun from the vantage point of an orbiting spacecraft, and as we on Earth cast our thoughts toward space. The Cassini spacecraft imaging team – led by Carolyn Porco – later dubbed this image The Day Earth Smiled. Learn more it, and see the first two images of Earth from deep space, by clicking on the links below.

The Day Earth Smiled image by Cassini, 2013

Pale Blue Orb image by Cassini, 2006

Pale Blue Dot image by Voyager, 1990

Mosaic of people on Earth waving at Saturn on July 19, 2013

View larger. | NASA’s Cassini spacecraft took this natural-color portrait on July 19, 2013, which is the first image to show Saturn, its moons, and rings, plus Earth, Venus, and Mars, all together. Image and Caption Credit: NASA/JPL-Caltech/SSI

View larger. | NASA’s Cassini spacecraft took this natural-color portrait on July 19, 2013. It’s the third-ever image of Earth from the outer solar system, and the first image to show Saturn, its moons, and rings, plus Earth and its moon, Venus, and Mars, all together. Image via NASA/JPL-Caltech/SSI. Read more about this image from NASA.

View larger. | Annotated image of Saturn and the view from Saturn, taken by Cassini spacecraft on July 19, 2013.

View larger. | Annotated image of Saturn and the view from Saturn, taken by Cassini on July 19, 2013. Image via NASA/JPL-Caltech/SSI

Via  NASA/JPL/SSI/CICLOPS / Mother Jones

Via NASA/JPL/SSI/CICLOPS / Mother Jones

The Day Earth Smiled image by Cassini, 2013. On July 19, 2013, NASA’s Cassini spacecraft had been orbiting Saturn and weaving in and among its moons since 2004. On that day, the spacecraft was aligned in such a way that Saturn eclipsed the sun as seen from its vantage point. With the sun’s light blocked, space scientists captured the third-ever picture of Earth from the outer solar system, and Earth’s moon, from hundreds of millions of miles away.

As Cassini slipped into Saturn’s shadow that day, it was also able capture images of the planets Venus and Mars, Saturn’s backlit rings, and several of Saturn’s moons, all at once.

The occasion defined the first time that people had advance notice they would be photographed from another world. NASA invited everyone on Earth to turn skyward and to wave as their image was taken from hundreds of millions of miles away. As the day approached, Carolyn Porco, Cassini imaging team lead at the Space Science Institute in Boulder, Colorado, said people should:

… look up, think about our cosmic place, think about our planet, how unusual it is, how lush and life-giving it is, think about your own existence, think about the magnitude of the accomplishment that this picture-taking session entails. We have a spacecraft at Saturn. We are truly interplanetary explorers. Think about all that, and smile.

Thus The Day Earth Smiled, the image above, was born.

NASA said this natural-color image is as the human eye would see it, if you had been there with Cassini. Using both its wide-angle and narrow-angle cameras, the spacecraft captured a total of 323 photographs over a four-hour period of time, but only 141 images were used to create this panoramic mosaic.

This incredible image – released by NASA in November, 2013 – spans a distance of 404,880 miles — roughly twice the distance from the Earth to the moon.

Cassini was about 898 million miles (1.44 billion kilometers) away from Earth at the time. That distance is nearly 10 times the distance from the sun to Earth.

Carolyn Porco also said:

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. This time, I wanted to turn the entire event into an opportunity for everyone around the globe to savor the uniqueness of our planet and the preciousness of the life on it.

She accomplished that, and more.

Click here to read more about The Day Earth Smiled image

An early raw image of the Earth and moon, as seen from Saturn by Cassini spacecraft on July 19, 2013. Earth is the brighter dot; moon to lower left.  Via NASA/JPL-Caltech/SSI.

An early raw image of the Earth and moon, as seen from Saturn by Cassini spacecraft on July 19, 2013. Earth is the brighter dot; moon to lower left. Via NASA/JPL-Caltech/SSI.

Not since NASA's Voyager 1 spacecraft saw our home as a pale blue dot from beyond the orbit of Neptune has Earth been imaged in color from the outer solar system. Now, Cassini casts powerful eyes on our home planet, and captures Earth, a pale blue orb -- and a faint suggestion of our moon -- among the glories of the Saturn system.  Image Credit:  NASA/JPL/Space Science Institute.  Read more about this image here.

This image is known as the Pale Blue Orb. The Cassini spacecraft captured it in 2006. Image via NASA/JPL/Space Science Institute.

Pale Blue Orb image by Cassini, 2006. The second-ever image of Earth from the outer solar system came in 2006, just two years after Cassini began orbiting Saturn, when the spacecraft was about 930 million miles from Earth.

As with the 2013 image, the 2006 image was made possible by the passing of Saturn directly in front of the sun as seen from Cassini.

Read more about the Pale Blue Orb image here or here.

This narrow-angle color image of the Earth, dubbed 'Pale Blue Dot', is a part of the first ever 'portrait' of the solar system taken by Voyager 1. The spacecraft acquired a total of 60 frames for a mosaic of the solar system from a distance of more than 4 billion miles from Earth and about 32 degrees above the ecliptic. From Voyager's great distance Earth is a mere point of light, less than the size of a picture element even in the narrow-angle camera. Earth was a crescent only 0.12 pixel in size. Coincidentally, Earth lies right in the center of one of the scattered light rays resulting from taking the image so close to the sun. This blown-up image of the Earth was taken through three color filters -- violet, blue and green -- and recombined to produce the color image. The background features in the image are artifacts resulting from the magnification.  Image Credit: NASA/JPL

This is a photo known as the Pale Blue Dot – the first of only three images of Earth taken from the outer solar system. The “dot” – our world, Earth – is on the right side of the photo, about halfway down. Image via NASA/JPL. Read more about this image here.

Pale Blue Dot image by Voyager, 1990. The first image ever taken of Earth from the outer solar system – and the most distant image, still – was acquired by NASA’s Voyager 1 spacecraft on February 14, 1990. Its distance from Earth at the time was 4 billion miles (6 billion kilometers) away. The image showed Earth as a pale blue dot. Hence the name. Voyager 1 had reached the edge of the solar system, 12 years after its launch and it had completed its primary mission. At the request of astronomer Carl Sagan, the spacecraft was commanded by NASA to turn around and photograph the planets of the solar system. The solar system mosaic was interesting, but this image – the image of our tiny world in space, surrounded by emptiness – was heart-rending. About this image, Carl Sagan later famously said:

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.

Read more about the Pale Blue Dot image and about what Carl Sagan said.

Bottom line: NASA’s Cassini spacecraft, now orbiting Saturn, took the third-ever picture of Earth from the outer solar system today’s date – July 19, 2013. The image came to be called The Day Earth Smiled. The other two pictures were taken in 1990 and 2006.