July 19, 2013 – The Day the Earth Smiled. On this date, humanity acquired its third-ever image – and one of the most awe-inspiring space photos ever – of Earth from the outer solar system. The planet Saturn eclipsed the sun from the vantage point of the orbiting Cassini spacecraft, and we on Earth cast our thoughts toward space and our tiny place in it. The imaging team later dubbed this image The Day the Earth Smiled. The two previous images – Pale Blue Orb image by Cassini in 2006 and Pale Blue Dot image by Voyager in 1990 are also discussed below.
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 and Earth’s moon, from the outer solar system, from hundreds of millions of miles away.
As Cassini slipped into Saturn’s shadow that day, it was also able to capture images of the planets Venus and Mars, Saturn’s backlit rings, and several of Saturn’s moons, all at once. You can see the dark side of Saturn, its bright limb, the main rings and the F ring, G and E rings. This view looks toward the unilluminated side of the rings from about 20 degrees below the ring plane.
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 the Earth Smiled was born. Porco was also involved with the planning of the earlier Pale Blue Orb and Pale Blue Dot images.
NASA said the 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 mosaic is also one of 33 “footprints” that cover the entire ring system and Saturn itself.
This incredible image – released by NASA on July 23, 2013 – spans a distance of 404,880 miles (650,000 km) – roughly twice the distance from the Earth to the moon. Cassini was about 898 million miles (1.45 billion km) away from Earth at the time. That distance is nearly 10 times the distance from the sun to Earth.
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 much more.
There is also another very cool associated image from this day, a collage of people on Earth, created to help celebrate the occasion. Over 1,400 individual photos come together to depict a view of the Earth. On the same day that The Day the Earth Smiled image was taken, participants from 40 countries took photos of themselves waving at Saturn. This awesome collage is the result. The images were streamed to NASA/ JPL-Caltech via Twitter, Facebook, Flickr, Instagram, Google+ and email.
Pale Blue Orb image by Cassini, 2006. This was the second-ever image of Earth taken from the outer solar system, taken on February 15, 2006, just two years after Cassini began orbiting Saturn. At the time, the spacecraft was about 930 million miles (1.5 billion km) from Earth. The Earth and moon appear as a tiny blue dot on the right side of the image, just above center. When magnified, you can just make out the moon as a slight “protrusion” on the upper left side of the 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.
You can read more about the Pale Blue Orb 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 (6.4 billion km). The image showed Earth as a pale blue dot, hence the name. Earth appears as a very tiny crescent only 0.12 pixel in size. 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, in part:
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.
Bottom line: NASA’s Cassini spacecraft, which orbited Saturn until 2017, took the third-ever picture of Earth from the outer solar system on today’s date, July 19, 2013. The image came to be called The Day Earth Smiled. This followed two previous similar pictures taken in 1990 and 2006.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.