Another Impact Event on Jupiter

Jupiter has been hit again and has the scar to prove it. Though occurring on the anniversary of the 1994 impact of first fragment of Comet Shoemaker-Levy 9, this new impact event is apparently not of the same scale of the multi-day event known as the “Great Comet Crash.” Still, it raises some interesting questions about what we should expect in the future.

Details of the impact, which was first observed by an amateur astronomer, can be found by clicking here.

Since we never saw the impactor, I suspect it was a wayward asteroid rather than a comet. Shoemaker-Levy 9 was captured by Jupiter’s gravity sometime in the 1920s and orbited undetected on Earth until something perturbed its path and sent it close enough to Jupiter that tidal forces broke it apart in 1993. That exposed its highly-reflective icy interior and created a swarm of mini-comets with visible tails.

This event could have been a direct hit rather than a capture event, in which case it could have been either a comet or a rocky body like a small asteroid. But capture and perturbation seems more likely. Since asteroids appear to be rubble piles, tidal forces would also break an asteroid apart. In that case, there may be signs of other impacts in the days to come.

I’m sure solar system experts will be creating models of various possibilities to determine both the likely composition of this impactor and the likelihood of future asteroid and comet impacts. Now that we have seen two such events only 15 years apart, it is reasonable to say that they are fairly common and that we can expect to see other insults to Jupiter in the future.

I have written about “The Great Comet Crash” in several of my children’s books. I had the good fortune to be able to interview the late founder of astrogeology, Gene Shoemaker, and his wife, comet-hunter par excellence Carolyn Shoemaker, in the summer of 1995. Their in-their-own-words profile appears in my young adult collection of interviews, To the Young Scientist (Franklin Watts, 1997).

I also wrote Beyond Jupiter (Joseph Henry Press, 2005), a full length biography of planetary astronomer Heidi Hammel, who gained national attention for her leadership of the Hubble Space Telescope’s imaging of the SL-9 impact.

Finally, the SL-9 event is one of several described in Collsion Course! Cosmic Impacts and Life on Earth (Millbrook Press, 2001).

Have a smashing great day!

Fred Bortz
Science Books for Young Readers
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