Comet 9P/Tempel 1 Impact
NASA's Hubble Space Telescope captured the dramatic effects of the collision early July 4 between an 820-pound projectile released by the Deep Impact spacecraft and comet 9P/Tempel 1.
This sequence of images shows the comet before and after the impact.
The image at left shows the comet about a minute before the impact. The encounter occurred at 1:52 a.m. EDT.
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 120 miles (200 kilometers) 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 traveling at about 1,200 miles an hour (1,800 kilometers an hour), or twice as fast as the speed of a commercial jet. The debris extends about 1,200 miles (1,800 kilometers) from the nucleus.
The potato-shaped comet is 8.7 miles (14 kilometers) wide and 2.5 miles (4 kilometers) long. Tempel 1's nucleus is too small even for the Hubble telescope to resolve.