Number 218 (Story #2), March 17, 1995 by Phillip F. Schewe and Ben Stein|
THE IMPRINT OF COMET SHOEMAKER LEVY on Jupiter has faded but the events surrounding the explosive encounter of July 1994 are relived in a suite of nine papers in the 3 March issue of Science. Some of the highlights are as follows: G. Orton et al. describe infrared observations, made with the NASA Infrared Telescope Facility, which suggest that after the impacts the abundance of stratospheric ammonia increased by a factor of 50 and that the north polar aurora brightened by a factor of 5 in the near infrared. H.A. Weaver et al., analyzing images made with the Hubble Space Telescope (HST), allow that there is still considerable uncertainty in the size of the largest fragments; estimates go as high as 4 km, but a size of less than 1 km cannot be ruled out. H.B. Hammel et al. report that the impacts were on average about eight minutes later than expected. Robert A West et al. suggest that the brown color of the debris particles comes from sulfur- and nitrogen-rich organic matter. In the core regions of the impact sites, the particles had a radius of 0.15 to 0.3 microns; later they coagulated into larger clumps. K.S. Noll et al. used ultraviolet spectra to identify several molecules never seen on Jupiter before, such as S2. Some scientists had suspected that the passage of charged cometary dust through the Jovian magnetic field would, through a sort of dynamo effect, trigger auroral emissions. Just such a display was observed in the far ultraviolet by R. Prange et al. Finally, James R. Graham et al. used the prodigious light-gathering power of the Keck Telescope to produce an infrared movie (7.7 sec per frame) of the fragment R collision. At its peak the resulting flare from the impact outshone Jupiter itself.