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.
Posted by Emily Lakdawalla on 2011/09/13 01:27 CDT
Jeff Moore's presentation was cool because of the discussion it stimulated. He considered what exogenic processes might be operating on Pluto's surface. What's an exogenic process? It's something that modifies the shape of the surface from the outside, and doesn't require the body to be geologically active inside.
Posted by Emily Lakdawalla on 2011/09/09 01:05 CDT
New Horizons Day 2: Tectonic features on icy worlds
Posted by Emily Lakdawalla on 2011/09/07 02:06 CDT
Here's a few pretty pictures that were recently dusted off by Ted Stryk. Pioneer 10 and 11 passed by Jupiter on December 4, 1973, and December 3, 1974, respectively. Here are three pictures from those two encounters, in versions newly processed by Ted from scanned photographic prints found during a research trip to NASA's Ames Research Center.
Posted by Emily Lakdawalla on 2011/08/30 11:27 CDT
New Horizons workshop, day 1: Chemistry & climate on Pluto & other cold places
Junocam will get us great global shots down onto Jupiter's poles