Saturn and Us

July 19, 2013 was a very special day in the history of humanity. From a distance of 898.414 million miles (1.445858 billion kilometers) from Earth, the Cassini spacecraft made this stunning mosaic of the ringed planet as it eclipsed the Sun. The result is nothing less than breathtaking:

Saturn, in all its majesty. Photo by NASA/JPL-Caltech/SSI

There is simply no way to adequately convey the beauty of this image in mere words. Instead, I invite you to view the colossal 9000×3500 pixel mosaic itself. Take a moment for it to load and just scroll around for a while. (Be sure to check out the annotated version of the mosaic as well.)

Cassini was “behind” Saturn in the sense that it was on the side of Saturn opposite the Sun. This gave the Cassini team an opportunity to create a mosaic of the entirety of Saturn and its rings backlit by the Sun.

The planet itself appears in silhouette, but not completely. Notice that part of Saturn’s dark side is illuminated by light reflected off the rings themselves. In other words, “Ringshine.”

"Ringshine" on Saturn's night side. Photo by NASA/JPL-Caltech/SSI
“Ringshine” on Saturn’s night side. Photo by NASA/JPL-Caltech/SSI

Cassini was about 17 degrees below the plane of the rings, allowing the rings to appear as an ellipse in this view. And that’s a good thing because it really allows us to explore the rings in a very unique way.

Enceladus with its geysers of ice crystals, creating its own silhouette. Photo by NASA/JPL-Caltech/SSI
Enceladus. Photo by NASA/JPL-Caltech/SSI

The outermost E-ring appears diffuse and ghost-like. It’s created by geysers of ice crystals erupting from Enceladus. If you zoom in on the left side of the image, sure enough you’ll spot Enceladus with geysers erupting!

There are several other moons to be seen in this image, and some background stars as well. But as amazing as this image is, what makes it truly interesting is that you, me, and everyone on Earth are in it.

The day Earth smiled

At the bottom right of the mosaic is a tiny pale blue dot. That’s us. That’s you and me and the whole of humanity right there on a tiny, pale blue dot.

Us, in the distance. Photo by NASA/JPL-Caltech/SSI
Us, in the distance on the lower right. Photo by NASA/JPL-Caltech/SSI
Earth and Moon. Photo by NASA/JPL-Caltech/SSI
Earth and Moon. Photo by NASA/JPL-Caltech/SSI

We are 898.414 million miles (1.445858 billion kilometers) in the background in this image. Zooming in reveals both our home planet and Moon. That’s all of us, right there, looking up toward Saturn, and smiling.

That’s what makes this image of Saturn so special, and why July 19, 2013 is a special day in the history of humanity. Human beings from all over that blue dot looked up toward Saturn while Cassini was taking its picture, smiled, and waved.

I was so happy I could take part in that opportunity to wave at Saturn with my wife, one of my closest friends, and the wonderful people of the Launch Pad Astronomy Workshop.

The class of 2013 from left to right: Jennifer Campbell-Hicks, Claudine Griggs, Douglas Dechow, Jay O'Connel, Jennifer Marie Brissett, Brenda Clough, Jamie Todd Rubin, Liz Argall, Andy Romine, Caren Gussoff, Chaz Brenchley, Jeri Smith-Ready, Anna Leahy, Doug Farren. Kneeling in front: Andria Schwortz, Me, Mike Brotherton
The class of Launch Pad 2013, waving toward Saturn. Our photographer even stood up on a rock so we’re actually looking straight along the line of sight toward Saturn 🙂

Here’s looking at you, Saturn!

Update 2013-11-14: Emily Lakdewalla from the Planetary Society has an excellent walkthrough of the image and explains why things appear the way they do in the image. It is well worth your time to have a watch (be sure to go full screen and HD so you can really spot the details):

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