File:HD189733 09.jpg

This movie simulates the orbit of HD 189733b as it first crosses in front of its parent star, then passes behind. Spitzer began observing the planet when it was between us and the star, with its cooler, dimmer night side in view. As the planet swept around, the hotter and brighter day side rotated into view, and the total infrared light measured by Spitzer went up. The size of this increase in infrared brightness over time told astronomers how the temperature across the entire surface of the planet varies Credit: NASA/JPL-Caltech/T. Pyle (SSC) Download the actual movie at http://www.cfa.harvard.edu/press/2007/pr200713_images.html. Used with permission, see http://www.cfa.harvard.edu/policies/image_use.html