NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) just completed a very cool assignment: watch how the light from a distant star is blocked by Pluto. As you might imagine, getting directly into Pluto’s star-shadow here on Earth is a pretty tricky task, especially since the Earth is moving pretty rapidly with respect to Pluto, and spinning on its axis to boot. But SOFIA is mounted in a 747, and can move to whatever location is necessary to do the job. SOFIA in flight. The opening in the back of the 747 is where the telescope is located. Because SOFIA can measure light very accurately, seeing how the star dims and brightens as it disappears and reappears behind Pluto tells scientists about its atmosphere. These results will provide data that supplements our scant knowledge of Pluto, the only solar system planet not yet visited by any of our robots (well, I…