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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.

Fountains of Water Vapor and Ice

Posted by Deepak Dhingra on 2015/01/22 11:22 CST | 2 comments

Deepak Dhingra shares some of the latest research on Enceladus' geysers presented at the American Geophysical Union (AGU) Fall Meeting in San Francisco last month.

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Ten years after the Huygens landing: The story of its images

Posted by Emily Lakdawalla on 2015/01/15 03:02 CST | 5 comments

The landing of Huygens on Titan was a significant moment for planetary science and a great accomplishment for Europe. But the Huygens landing also stimulated the development of the international community of amateur image processors that does such great work with space images today. I was in the midst of it all at the European Space Operations Centre in Darmstadt.

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JUICE at Europa

Posted by Van Kane on 2015/01/13 02:03 CST | 7 comments

Europe's JUICE spacecraft will provide us with a detailed regional study of this icy moon of Jupiter.

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Riding With Cassini Through 2014

Posted by Bill Dunford on 2014/12/31 06:13 CST | 1 comment

Video: see some of the sights Cassini saw this year.

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Revisiting Uranus with Voyager 2

Posted by Björn Jónsson on 2014/12/10 10:44 CST | 2 comments

Amateur image processor Björn Jónsson brings us some new views of Uranus from reprocessed Voyager 2 data.

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Join me in Washington, D.C. for a post-Thanksgiving Celebration of Planetary Exploration

Posted by Casey Dreier on 2014/11/26 11:54 CST

See Bill Nye, Europa scientist Kevin Hand, and Mars scientist Michael Meyer speak at a special event on Capitol Hill on December 2nd.

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A (Difficult) Day in the Solar System

Posted by Bill Dunford on 2014/10/30 10:05 CDT | 13 comments

After a bad day on the launch pad, some perspective.

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45th Binghamton Geomorphology Symposium Report

Posted by Ted Stryk on 2014/09/23 12:15 CDT | 1 comment

The 45th Binghamton Geomorphology Symposium, usually focused on terrestrial studies, shifted this year to planetary science. Ted Stryk gives us an overview.

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Europa: How Less Can Be More

Posted by Van Kane on 2014/08/26 06:55 CDT | 6 comments

Van Kane explains three factors that make exploring Europa hard—factors that can make a mission concept that seems like less actually be more.

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Best-ever Neptune mosaics for the 25th anniversary of Voyager 2's flyby

Posted by Emily Lakdawalla on 2014/08/25 10:58 CDT | 4 comments

In honor of the 25th anniversary of the Voyager 2 flyby of Neptune, image magician Björn Jónsson has produced two new global mosaics of the distant ice giant, the highest-resolution ever made.

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