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Name: Gerry A Adams and Charlie H Bell
Status: Other
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Guten Tag from Germany.

My question concerns the Jupiter-comet event that will take place in July.

1. What is the name of the comet and what is it?
2. What are the expected results of this collision?
3. What is the best guess as to when it will happen?
4. Do you know of any good resources for teaching astronomy to junior high schools kids.

Again, thanks!

Tschuss Gerry Adams

The comet's name is P/Shoemaker-Levy 9 (I do not know what the "P" means). At least 21 fragments of this comet will collide with Jupiter during July 16-22. Current best estimate for the first major fragment's impact is 19:5- 3:40 Universal Time (with an uncertainty of 8.4 minutes). (This figure was issued by P. W. Chodas, D. K. Yeomans and Z. Sekanina of JPL/Caltech and P. D. Nicholson of Cornell, as of July 5). No one is certain what the effects will be because the sizes of the fragments are not known for certain (although the 11 largest are believed to be 2-4 km in diameter), and it is not known to what extent each fragment will hold together once it plows into Jupiter's atmosphere. There are several possible scenarios; the fragments may disintegrate in the upper atmosphere, or they may manage to penetrate to some depth in the atmosphere. There may be flashes bright enough to momentarily brighten one or more of Jupiter's moons. If the fragments penetrate deeply enough, they may cause material from Jupiter's lower atmosphere to erupt through the cloud tops (which are all we can normally see of Jupiter). None of the collisions will be directly observable from Earth, but the spacecraft Galileo will be able to "see" the impacts, and with luck there will be some visible effect as the impact sites rotate into view.

There is lots of astronomy stuff (text and images) available in the World Wide Web (WWW); you need a browser (like Mosaic) to navigate through it all.

Update--I obtained this info via anonymous ftp from The following is excerpted from material in the file comet.faq which resides in the /pub/comet directory. There are a number of files there which may be of interest, including some images from last March of the Shoemaker-Levy frag- ments (in GIF and Postscript formats). Be warned--the image files are big (~ half a Meg for the Postscript (.ps) files). There is a bunch more info in comet.faq which I have not quoted. "The shattered comet Shoemaker-Levy 9 (1993e) is expected to collide with Jupiter over a 5.6 day period in July 1994. The first of 21 comet fragments is expected to hit Jupiter on July 16, 1994 and the last on July 22, 1994. All components of the comet will hit on the dark far side of Jupiter, out of sight from Earth. "Although [the expected points of impact] are still all on the far side as viewed from the Earth, they are now only 5-9 degrees behind the limb. About 12 - 24 minutes after each hit, the impact points will rotate into view as seen from Earth. Anything ejected higher than 500-1000 km above the cloud tops during the impacts will be visible from Earth."

RC Winther

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