Only Voyager 2 has visited the ice giants, Uranus (left) in 1986 and Neptune (right) in 1989. These Voyager portraits are newly reprocessed to show the 2 planets at correct relative size and color. Since Voyager, planetary astronomers have studied the ice giants from Earth and have seen their faces change.
Emily Lakdawalla and Loren A. Roberts for The Planetary Society based on data from exoplanets.org
A Comparison of Mass and Radius for Discovered Planets
This graph displays all exoplanets with measured diameters and masses. Rocky planets form a tight line (lower left), but super-Earths/mini-Neptunes have widely varying atmospheres and densities. At Jupiter’s size, increasing mass no longer increases the diameter of a planet (upper right). Most of Kepler’s discoveries would be in the super-Earth/mini-Neptune region, but few of them have measured masses, so they do not appear here.
In this issue’s pages you’ll also get updates on Planetary Society projects from Deep Drill to LightSail to our advocacy efforts in Washington. You’ll also learn about a crucial planning effort that has been a long time coming. In “Your Place in Space,” Bill Nye presents you The Planetary Society’s strategic framework [link], which clarifies our mission, our vision, and the scope of our activities. I’m excited to do the work to fulfill those plans through the coming five years.
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