Expert: James Gort - 6/9/2005

Question
I have read much of the impact of Shoemaker Levyon Jupiter, what I want to know is...

How big were the fragments?
Haw fast were they travelling on atmosphere entry? Were they all the same speed?
How far would they plunge into jupiter before stopping?

Thank you...

John

Answer
Hello John,

About 20 large fragments (which were seen and identified from space and ground observatories) collided with Jupiter - these fragments were from one to three kilometers in diameter.  All were travelling at about the same velocity - 60 km/s relative to the planet.  But there were literally millions of smaller fragments - ranging from huge boulders to microscopic particles.

The question of how far the large fragments penetrated is being debated.  Some people are looking at spectral lines to see where in the atmosphere the "explosion" occurred.  It's still inconclusive.  But the larger fragments did explode violently as their kinetic energy was converted to heat and  as Jupiter's atmosphere was dramatically compressed.  Plumes were seen extending several thousand km above the cloud tops (due to the explosions), so it is likely that the explosions ocurred at least that far below the cloud tops.  Best estimate - the large fragments exploded between 3000 and 6000 km from the cloud tops, in agreement with the observed plumes starting about two minutes after the fragments entered the atmosphere.  The fragments were broken apart and partially vaporized by the explosion, but it is likely that some fragments continued to fall, and now reside deep inside Jupiter's gaseous interior.

Hope that helps.

Prof. James Gort