SL9 Impact Surprise

SL9 Impact Surprise

Astronomers were discouraging the public from expecting too much.
In the days before the event, astronomers all over the world were discouraging the public from trying to see the comet crash through a small telescope.

Some predictions gone awry.

Donald Savage July 7, 1994 NASA Headquarters, Washington, DC.

"Because of its small size, most scientists do not expect to witness
significant visible effects from the impact of the first fragment,
nor to detect significant after-effects in the planet's
atmosphere."

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Paul Weissman July 13, 1994 in _Nature_ July 14, article titled: 
"The Big Fizzle is Coming"

"Each snowball will individually ablate and burn up like a meteor in
Jupiter's upper atmosphere. Lacking the momentum and the structural
integrity of a single solid body, they will likely not penetrate
deeper into the atmosphere where they might explode with
multi-thousands of megatons of energy.

Thus the giant impacts will produce a spectacular meteor shower, but
not the massive fireball explosions that have been predicted by some
researchers. The impacts will be a cosmic fizzle."

BAM!

World's astronomical community thrown off its feet.

When fragment A hit Jupiter at more than 200,000 mi/hr shortly after 4pm EDT, July 16, 1994, it threw up a fireball so bright it seemed to knock the world's astronomical community off its feet. The event was visible in even a 2 inch refractor at 75X magnification.

(12 minute sequence of a plume near Jupiter's limb from fragment A.)

These sequence of images show evidence for a plume near the terminator of Jupiter at the time of the A impact. A bright feature appears 1000-1500 km above the limb of Jupiter at 20:18:17 in the 953nm filter. (An image at 20:15:17 did not show a detached feature.) A possible interpretation was that the feature was visible by reflected sunlight, and the apparent detachment is due to the shadow of Jupiter on the plume. During the temporal sequence from top to bottom, spreading of the feature is clearly resolved. The feature is visible at wavelengths ranging from the ultraviolet through the near infrared. Photo Credit: HST Jupiter Imaging Science Team

By July 20th, the evolution and order of the impact sites became very confusing.

Huge dark halos surrounded each major impact with dusky streamers; knots and shadowy debris muddied the planet's south polar region. New white clouds and eddies seemed to suddenly appear, further complicating the impact sites. By the time the last fragment hit Jupiter on July 22, Comet Shoemaker Levy 9 had been transformed into a shocking procession of incinerated comet corpses lying on top of Jupiter's stratosphere.

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