Comet Outburst Caught by Hubble

As a result of Comet Tempel 1's increasing proximity to the Sun, several outbursts have been seen erupting on the comet's surface. These outbursts, consisting mainly of water vapor and carbon dioxide, are the result of parts of the comet's icy surface heating up from the Sun's heat. These outbursts occur approximately once every 42 hours (the period of the comet's rotation about its axis), and the last such outburst is expected to occur 4 hours prior to Deep Impact's collision with the comet. One of these outbursts was caught by the Hubble Space Telescope, as seen in the image above.