SL9 Impact W (last fragment)

From Galileo

The picture was taken by NASA's Galileo spacecraft of an impact of a fragment "W" of Comet Shoemaker-Levy 9 at Jupiter. The black-and-white image of the collision of comet fragment W consists of four frames taken over a 7-second period at intervals of 2 1/2 seconds. It shows the beginning, brightening and fading of a bright point about 44 degrees south latitude on the far side of Jupiter from the Earth. The four frames were obtained on July 22, 1994, at a distance of about 150 million miles from Jupiter. South is down, and Jupiter is about 60 pixels across, corresponding to a resolution of 2400 km. Photo Credit: Galileo Spacecraft Team and NASA.

Mystery: Hubble and Galileo saw W impact at the same time!

The Hubble Space Telescope and Earth-based observatories saw some of the impacts start just as soon as Galileo did- as if looking through Jupiter! "In effect, we were apparently seeing something that we didn't think we had any right to see," said Dr. Andrew P. Ingersoll of the California Institute of Technology, a member of both the Hubble Space Telescope and Galileo science teams.

There are possible explanations for the timing of the reported observations. "If everyone's times are right -- and we think they are -- it seems clear that something was happening high enough to be seen beyond the curve of the planet, before and during the events Galileo saw," said Galileo Project Scientist Dr. Torrence V. Johnson of JPL. "The Hubble observations of fragments G and W could conceivably be due to scattering of light from Galileo events off comet dust or other material at very high altitude," Johnson added, "but how the material got there is another question. There may have been earlier, smaller impacts going on that were too faint for Galileo to detect." In other words, some of the initial flashes may have been streaks left when comet chunks first hit the upper atmosphere, broke into smaller bits and burst into flame. It's similar to what we see when a meteoroid hits the Earth's atmosphere, leaving the blazing streak known as a shooting star.

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Last Modified by Amara Graps on 26 November 2003.
© Copyright Amara Graps, 1995-2003.