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):

An Overhead View of Saturn

On October 10, 2013, the Cassini spacecraft took an image of Saturn that is unlike anything we’ve ever seen from Earth:

Overhead View of Saturn
Saturn captured by Cassini in red, green, and blue-filter images on October 10, 2013. Click to enringulate. Image credit: NASA / JPL / SSI / Gordan Ugarkovic

It’s unlike any view of Saturn we’ve ever seen from Earth because it’s a view we can never see from Earth! Cassini captured Saturn and it’s rings from high above the planet’s northern hemisphere on October 10, 2013. The image shown here is actually a composite of several mosaic images of Saturn and its rings taken in red, green, and blue filters.

And what an image it is! In a rare glimpse we see Saturn as its own planet, detached from its rings. Of course, we already knew that about Saturn, but seeing it this way seems to add a whole new…well…perspective.

The image reveals some striking features of the planet. At the north pole is a 1,250 mile-(2,000 kilometers) wide vortex with wind speeds up to 330 mph (150 meters per second). There’s no land mass on Saturn to break this storm and it’s likely that it’s been there since long before Cassini ever arrived, and will probably remain there for  centuries  to come.

The storm sits at the center of a complex region known as the hexagon, shown in light blue in this image.  Each side of the hexagon is over 8,600 miles (13,800 km) in length – more than the diameter of Earth itself! For some reason though, there is no similar hexagon in Saturn’s southern hemisphere.

Looking at the rest of the image, the first thing that jumped out at me was that you could still clearly see the night side of the planet. That’s because Saturn is being illuminated by the rest of the ring system itself!

Had they been able to, I’m sure NASA would have processed the images and shared it with the public in a press release. But due to the government shutdown, no image was produced. Fortunately, the raw data is public and  Gordan Ugarkovic at created this spectacular image on his own initiative.

On a personal note, I’m extremely grateful for this image because it was taken on October 10, my birthday. So thank you Cassini, and thank you Gordan for an amazing birthday present! 🙂

Waltz Around Saturn

Around Saturn
‘Around Saturn’ by Fabio Di Donato

It’s hard to believe that the Cassini spacecraft has been in orbit around Saturn for nearly a decade now, returning one amazing image of the ringed world and its moons after another. The images are nothing short of breathtaking, but often only become so after some careful work has been done by humans here on earth to remove artifacts, add colors, and general image processing that must be done to make sense of astronomical data.

But there’s a kind of gritty beauty in the raw, unprocessed images as well, so when filmmaker Fabio Di Donato synced them to Shostakovich – Jazz Suite No.2: VI. Waltz 2, the result is a thing of beauty:

Around Saturn from fabio di donato on Vimeo.

I’ve been watching this video over and over again for the last several days and every time I do, I see something new in it. The intricate patterns of the ring system, it’s outer F-ring being deformed by Prometheus, Mimas floating by, the spongy texture of Hyperion, and the eye of Iapetus give the feel that the moons of the Saturn system are all in a kind of cosmic dance.

And what a beautiful dance it is! The whole thing looks like something directed by Stanley Kubrick and David Lynch using a silent film-era movie camera.

The whole video is a joy to watch, and a beautiful portrait of exotic, alien worlds right here in our cosmic front yard.

In Saturn’s shadow, part deux

The Cassini mission to Saturn has given us one astonishing view of the ringed planet and its moons after another since 2004, but this is one for the books:

Saturn’s night side, as seen by Cassini on Oct. 17, 2012 at a distance of approximately 500,000 miles (800,000 kilometers) from Saturn. Get the full-resolution image here! Image credit: NASA/JPL-Caltech/Space Science Institute

Is that amazing or what? And you really have to get the full-resolution, 6672×3104-pixel image to really grok the awesomeness. This image was created on October 17, 2012 by the Cassini spacecraft while Saturn was backlit by the Sun. In other words, this is Saturn’s night side. The image was taken when Cassini was looking “up” towards Saturn’s equator from an orbital latitude of about 19 degrees. The result is a stunning image of the planet’s silhouette, surrounded by the backlit rings.

There is a lot going on here and Phil Plait has a great breakdown of all of the features of the image, so I’ll refer you there. But I should like to point out that the green glow is light reflected by the rings onto Saturn’s cloud tops. In other words, forget moonlight, this is ringlight!

Another feature that is really cool is the diffuse band of light toward the bottom of the image. This is the outermost E-ring, which is the least dense and most diffuse of the rings. This ring comes courtesy of Saturn’s moon Enceladus, which spews geysers of water vapor and ice as it orbits Saturn.

Enceladus in Saturn’s E-ring. Enceladus appears as the dark spot in the middle of the flare at center. Image credit: NASA/JPL/Space Science InstituteNASA/JPL/Space Science Institute

It’s worth mentioning that these colors aren’t real, but are a combination of infrared, red and violet spectral filters. When combined, Saturn takes on a serene, eerie hue that reveals subtle details in its atmosphere that you simply cannot get any other way.

Since the only way to obtain an image like this is when the Cassini spacecraft is directly behind Saturn, such images are very rare. The last time this sort of image was taken was back in 2006. During that encounter, images were taken using filters to create a natural-color view of the backlit planet:

In Saturn’s Shadow – the Pale Blue Dot. Image credit: NASA/JPL/Space Science Institute

And if you haven’t, you must click that image for the full view. If you look carefully, you’ll see a pale blue dot in that image on the left side just inside G-ring. That’s Earth. That’s home. That’s us.

And we made this.

Mimas is just a speck

Once in a while, an image comes along that really helps to put the sheer size of Saturn into perspective. Check this out:

Saturn and its moon Mimas (little white speck at the top center) taken by the Casini spacecraft in near-infrared on August 20, 2012. Image credit: NASA/JPL-Caltech/Space Science Institute. Get the full-size version here.

Is that beautiful or what? This is a near-infrared image of Saturn taken by the Casini Spacecraft on August 20, 2012. Casini was about 18 degrees south of Saturn’s equator. Sunlight was coming in from the northern latitudes, so the rings are backlit and cast a deep shadow “band” in Saturn’s southern hemisphere.

But take a look at the full-size version of the image. See that little speck up top? That’s Saturn’s moon Mimas, and it’s just a speck!

Mimas, taken by the Casini orbiter. Image credit: NASA/JPL-Caltech/Space Science Institute.

Now as moons go, Mimas is rather small, just 246 miles (396 kilometers) across. But it’s easy to lose sight of exactly how small that is compared to Saturn when we see images of the moon or of the planet by themselves.

And Saturn is big. Really big. Like, 74,897 miles (120,536 kilomieters) across at it’s equator big.

Obviously, 74,897 is way more than 246, but it’s hard to comprehend the vast difference in scale between these two worlds until you can see them together like this. It’s a visual reminder of the sheer diversity of worlds within our solar system.