On the Cover: Although some scientists believe Mars’ giant polygons may be further evidence of ancient oceans on the Red Planet, their exact origin remains a mystery. These giant polygons—in the southern Utopia area of Mars’ northern lowlands—are surrounded by relatively straight troughs. This image, taken by the Context Camera (CTX) on Mars Reconnaissance Orbiter, is about 29 kilometers (18 miles) across, and most of the polygons shown are between 8 and 15 kilometers (5 and 9 miles) across.
2 Bruce Murray: 1931-2013: Louis Friedman remembers our co-founder and friend.
8 The Enigmatic Polygons of Mars: Dorothy Oehler explains how giant polygons might have formed on Mars.
13 Forging a New Consensus: Casey Dreier reports on our progress in Washington.
14 Upgrades to the Search: Bruce Betts on improved SETI and Exoplanet Telescope Searches.
17 Power From the Isotopes: Casey Dreier discusses restarting plutonium-238 production.
Planetary Society Kids: What happens when hot lava cools?
4 Your Place in Space A heartfelt “Thank You” from Bill Nye.
6 Planetary Radio Online radio brings exciting guests!
6 On Planetary.org What’s happening online?
7 Q&A Ganymede’s liquid layer.
15 What’s Up? Comet ISON and a hybrid solar eclipse.
16 Members’ Dialogue We hear you!
23 Snapshots From Space Europa in beautiful color.