Here is the third-ever image of Earth – taken on July 19, 2013, aka the day Earth smiled. The wide-angle camera on NASA’s Cassini spacecraft captured Earth and the moon, plus Saturn’s rings, in the same frame. Earth appears as a pale blue dot, while the moon is stark white. NASA says this is only one “footprint” in a mosaic of 33 footprints covering the entire Saturn ring system (including Saturn itself). At each footprint, images were taken in different spectral filters for a total of 323 images: some were taken for scientific purposes and some to produce a natural color mosaic. This is the only wide-angle footprint that has the Earth-moon system in it.
What you’re seeing here is the dark side of Saturn, its bright limb, the main rings, the F ring, and the G and E rings. The limb, or edge of Saturn against the backdrop of space, and the F ring are overexposed. The breaks in the brightness of Saturn’s limb are due to the shadows of the rings on the globe of Saturn, preventing sunlight from shining through the atmosphere in those regions. The E and G rings have been brightened for better visibility.
Earth, which is 898 million miles (1.44 billion kilometers) away in this image, appears as a blue dot at center right; the moon can be seen as a fainter protrusion off its right side. Earth and moon are clearly seen as separate objects in the narrow-angle image below. Earth is the blue point of light on the left; the moon is fainter, white, and on the right.
Bottom line: Much-awaited photos of the Earth and moon, as seen from the darkside of Saturn during an eclipse of the sun by Saturn on July 19, 2013. This is only the third time ever that Earth has been imaged from the outer solar system.
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.