Outer Planets

Jupiter. Saturn. Uranus. Neptune. Each of these giant planets is the center of its own miniature solar system. Each is spectacularly beautiful and scientifically fascinating, which are reasons enough to explore them. But by studying the giant planets and their rings and moons, we can also learn about the forces that operated during the formation of our own solar system, as well as the origins of the hundreds of new extrasolar planetary systems that we discover every year.

And their moons are worlds in their own right. There are at least 16 outer planetary moons that would be called dwarf planets if they orbited the Sun rather than a planet. Two (Jupiter's Ganymede and Saturn's Titan) are larger than the planet Mercury, and one (Triton) is probably a captured Kuiper belt object.

But it is challenging and expensive to explore the outer planets, and missions to the outer planets take a very long time to develop, fly, and operate. Cassini will be orbiting Saturn until 2017, and Juno will operate at Jupiter from 2016 to 2017. After that, it's not clear if anyone will be sending a followup mission to Saturn or Jupiter or its moons, or an orbiter to survey the Uranus or Neptune systems. And there is a critical shortage of the isotope of plutonium that is needed to generate power for outer planetary missions.

Instruments for the JUICE Jovian Mission

Posted by Van Kane on 2013/03/07 12:20 CST | 6 comments

The European Space Agency (ESA) announced the list of instruments selected for its JUICE mission to explore the Jovian system for three years starting in the 2030 following a 2022 launch.

Meteor showers on Titan: an example of why Twitter is awesome for scientists and the public

Posted by Emily Lakdawalla on 2013/03/06 12:48 CST | 5 comments

I use a variety of social networking tools to perform my job, but there's one that's more important and valuable to me than all the rest combined: Twitter. Yesterday afternoon there was a discussion on Twitter that exemplifies its value and fun: are there visible meteors on Titan?

Sea Salt

Posted by Mike Brown on 2013/03/06 10:41 CST | 3 comments

Ever wonder what it would taste like if you could lick the icy surface of Jupiter’s Europa? The answer may be that it would taste a lot like that last mouthful of water that you accidentally drank when you were swimming at the beach on your last vacation.

The Stormscapes of Saturn

Posted by Bill Dunford on 2013/03/04 12:25 CST | 2 comments

Look past the rings, and Saturn is even stranger--and more breathtaking.

Voyager captured this view of Uranus' moon Umbriel from a range of slightly more than a million kilometers on January 24, 1986. Processed by Ted Stryk.

Mysterious Umbriel

Posted by Ted Stryk on 2013/02/28 12:59 CST | 1 comments

Presenting a newly-processed version of Voyager 2's best images of Uranus' moon Umbriel.

Arc of Ice and Light

Posted by Bill Dunford on 2013/02/18 10:20 CST | 2 comments

When the sunlight catches it just right, Saturn's F Ring is something to see.

Saturn's Hexagon Viewed from the Ground

Posted by Leigh Fletcher on 2013/02/01 05:49 CST | 2 comments

For the first time, amateur astronomers are capturing spectacular images of Saturn's bizarre north polar hexagon.

Pretty picture: Neptune and Triton

Posted by Emily Lakdawalla on 2013/02/01 12:29 CST | 6 comments

On a lonely evening, what is one to do but to dip into archival space image data and surface with a gorgeous photo of a crescent Neptune and Triton?

Enceladus: A problem of contrast

Posted by Emily Lakdawalla on 2013/01/30 07:00 CST | 6 comments

Time for my quarterly foray into the Cassini archival science data! The very first image I downloaded from the January 1, 2013 data release presented an interesting challenge to my image processing skill. I'll show you the pretty picture of Enceladus and then explain how I processed it.

High-resolution Voyager 1 view of Jupiter with Io and Europa

Voyager 1 revisited: Io and Europa transiting Jupiter

Posted by Björn Jónsson on 2013/01/22 06:04 CST

What is the highest resolution global Jupiter mosaic that includes a satellite transit that can be assembled from Voyager images? Satellite transits are especially beautiful when the resolution is high enough for some details to be visible on the satellites so I decided to check this. And I was remarkably lucky.