COMET VS SOLAR WIND: Comet Nishimura entered the field-of-view of STEREO's inner Heliospheric Imager (HI-1) on September 17th. This movie shows considerable interaction of the comet's ion tail with the solar wind, along with a possible glancing blow from a coronal mass ejection in the September 22-23 timeframe. Toward the end of the movie, at the start of the day on September 23, the comet appears fainter and the movie appears to slow down. This is due to a pre-planned change in the observing mo

Celestial objects often come in icy and rocky flavors. Asteroids are like the solar system's leftover rocky debris, while comets are more like giant cosmic dirty snowballs. Both orbit the sun, but one might put on a dazzling light show when it gets close! | The Brain Maze