Hubble captures Deep Impact's collision with a comet
This sequence of images shows the comet before and after the impact. The image at left shows the comet 10 minutes before the impact. The encounter occurred at 7:52 a.m. CEST In the middle image, captured 15 minutes after the collision, Tempel 1 appears four times brighter than in the pre-impact photo. Astronomers noticed that the inner cloud of dust and gas surrounding the comet's nucleus increased by about 200 kilometres in size. The impact caused a brilliant flash of light and a constant increase in the brightness of the inner cloud of dust and gas. The Hubble telescope continued to monitor the comet, snapping another image [at right] 62 minutes after the encounter. In this photo, the gas and dust ejected during the impact are expanding outward in the shape of a fan. The fan-shaped debris is travelling at about 1,800 kilometres an hour, or twice as fast as the speed of a commercial jet. The debris extends about 1,800 kilometres from the nucleus. The potato-shaped comet is 14 kilometres wide and 4 kilometres long. Tempel 1's nucleus is too small even for the Hubble telescope to resolve. The visible-light images were taken by the Advanced Camera for Surveys' High Resolution Camera.The Hubble Space Telescope is a project of international cooperation between ESA and NASA. Image credit: NASA, ESA, P. Feldman (Johns Hopkins University), and H. Weaver (Applied Physics Lab)