When pieces of a shattered comet smash into the planet Jupiter
this summer, scientists worldwide will conduct one of the largest
coordinated astronomical observations in history.
In addition to scientific curiosity, there also is a
fascination akin to watching someone else's house get battered by a
force of nature.
"Virtually every telescope in the world will be pointed toward
Jupiter in July," Lucy McFadden, a University of Maryland
astronomer, said Wednesday at a National Aeronautics and Space
Administration news conference.
All the major observatories in the world, along with a fleet of
satellites, will focus on Jupiter as 20-some fragments of the
Shoemaker-Levy 9 comet collide with the planet and release about 1
million megatons of energy.
The first impact is expected on July 16, and more fragments
will slam into Jupiter, like train cars derailing one after the
other, over the next week.
"This is the first time in history we've been able to predict a
major impact and then prepare to observe it scientifically," said
Gene Shoemaker, a U.S. Geological Survey scientist who is
co-discoverer of the comet.
Just what will happen at impact is an open question. Some
scientists predict that each impact will produce an explosive
flash, followed shortly after by an erupting fireball. Others
suggest that dust from the comet fragments will disrupt the magnet
envelope surrounding the planet and cause visible changes. Chemical
reactions would send clouds above the gas that cloaks Jupiter,
creating wispy scars that may last for years.
Or, said Shoemaker, it could all be a dud.
Jupiter, though 11 times larger than Earth and the largest
planet in the solar system, is actually mostly gas. Objects falling
in could just disappear. But the speed of the comet, more than
100,000 miles per hour, is expected to release enough energy to
produce at least some reaction, even in Jupiter's gas.
"The worst case would be if they all just disappear, and there
is no effect," Shoemaker said. "But I will really be astonished if
we don't see something."
The comet was discovered by a team led by Shoemaker that
conducts a small, ongoing project searching the heavens for comets
using an old 18-inch telescope at the Palomar Observatory near San
Shoemaker's wife, Carolyn, made the first sighting when she
examined a photographic plate taken by the telescope on March 23,