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.

Planetary Society Hangout: Jan 10th, 2013 - AAS Coverage with Astronomer Meg Schwamb

Posted by Casey Dreier on 2013/01/10 01:00 CST | 1 comments

Join Casey Dreier and Emily Lakdawalla as they are joined by Dr. Meg Schwamb from Yale University. They will discuss the latest announcements from the American Astronomical Society 2013 conference and Dr. Schwamb's research in outer solar system bodies.

Jupiter and Io from Pleiades-1B (animation)

Pretty picture: Jupiter photo from an unusual source

Posted by Emily Lakdawalla on 2012/12/26 01:02 CST | 4 comments

A recently launched Earth-observing satellite is using the stars to practice its pointing, and caught a neat animation of Jupiter.

Planetary Society Weekly Hangout, Thu Dec 20 1200PT/2000UT: Making Titan in the laboratory with Sarah Hörst

Posted by Emily Lakdawalla on 2012/12/19 10:06 CST | 3 comments

Join us for our weekly Google+ Hangout Thursday at noon PT / 2000 UT. This week, I'm excited to have as a guest Sarah Hörst. Sarah is a postdoc at the University of Colorado whose current line of research involves experimental work on the complex atmospheric chemistry of Titan. She is also applying to be an astronaut!

That amazing image of Saturn's north pole just got better: now, it moves!

Posted by Emily Lakdawalla on 2012/11/28 11:27 CST | 2 comments

Remember the amazing photo of Saturn's north pole that I posted yesterday? Now, thanks to an amateur image processor, it moves, and the motions of the individual clouds within the belts are mesmerizing.

Raw image of Saturn's north polar vortex

Staring into Saturn's baleful eye

Posted by Emily Lakdawalla on 2012/11/27 11:12 CST | 12 comments

Amazing photos have just come back from Cassini, of swirling clouds surrounding Saturn's north pole.

Alan Stern Returns to Planetary Radio

Posted by Mat Kaplan on 2012/11/27 04:08 CST

The New Horizons Pluto mission PI provides an update, and introduces his new public project called Uwingu.

Watching the slow shift of seasons on Titan

Posted by Emily Lakdawalla on 2012/11/06 02:45 CST | 1 comments

A sharp-eyed amateur noticed two images of Titan taken 20 months apart from nearly exactly the same perspective, and they illustrate how the shifting of Saturn's seasons has brought change to Titan's atmosphere.

A huge color global view of Dione

Posted by Emily Lakdawalla on 2012/10/23 02:33 CDT

From the Cassini data archives comes a huge (5000 pixels square!) color image of Saturn's icy moon Dione, worth investigating from both near and far.

High signal-to-noise images of Uranus from Keck II

DPS 2012: The most detailed images of Uranus' atmosphere ever

Posted by Emily Lakdawalla on 2012/10/22 04:14 CDT | 3 comments

New ground-based images of Uranus show more finely detailed structure than any photos I have ever seen.

DPS 2012, Day 5: How to make asteroids crunchy on the outside and soft in the middle

Posted by Emily Lakdawalla on 2012/10/19 07:53 CDT | 2 comments

A summary of just one talk from the Division for Planetary Sciences meeting, by Lindy Elkins-Tanton, which provided a neat explanation for how asteroids can be melted and layered on the inside yet have a primitive-looking exterior.