The Cutting Edge: COMPUTING / TECHNOLOGY / INNOVATION : Impact on Jupiter Has Few Reverberations
Nothing spurs science and technology on as much as a devastating tragedy like a great earthquake, or a perceived common enemy like the old Soviet Union. Money becomes readily available, inquiring minds become energized, and we learn quickly how to build safer structures and bigger bombs.
So when the world watched in awe last year as comet Shoemaker-Levy smashed into Jupiter with a stunning show of force, a handful of scientists across the nation had reason to believe their time had finally come. At last people would realize the awesome power of a celestial object colliding with a planet, and political leaders would make a few million dollars available each year to create a program that might end the threat that such an object would ever hit the Earth.
The Jupiter extravaganza punctuated several recent studies that indicate a mile-wide asteroid could wipe out human life if it collided with this planet. A few scientists who believe that threat, as remote as it may seem, should not be ignored have labored for years to identify asteroids that could pose a threat to the Earth. And so they watched with relish as the Jupiter impact galvanized public interest in their underfunded programs. Surely, now, the money would come through.
But it didn’t work out that way.
“I would guess the search effort is about half of what it was a year ago” when Shoemaker-Levy crashed into Jupiter, says David Morrison, head of the space science division at the National Aeronautics and Space Administration’s Ames Research Center in Northern California.
Some programs have been eliminated, and others scaled back, despite the dramatic warning from the Jovian planet.
What went wrong?
The Jupiter impact brought about “a change in public consciousness, but I haven’t seen that transformed into a large change in the Congress” or any of the various agencies that could also search for asteroids that are on a collision course with Earth, says Morrison, who has argued for years for a comprehensive detection program.
“We haven’t exploited it very well,” he says.
Shoemaker-Levy’s stunning show coincided with a new national agenda that makes funding for new projects, regardless of how compelling they may be, almost impossible.
“I think it’s difficult in this environment to start anything new,” Morrison says. Far from seeing the inauguration of a new national program (at a cost of about $5 million a year) that would have provided a warning several decades before a large asteroid could hit the Earth, scientists have seen their federal funding dip below $1 million.
It has been a bitter disappointment for people like Tom Gehrels of the University of Arizona’s Lunar and Planetary Laboratory. Gehrels, who has carried out pioneering research with a computer-controlled telescope that sweeps the heavens for signs of moving objects, has seen his budget cut by about 18%.
And far from helping, the Jupiter impact actually strained his budget even more. Now, it seems everybody wants to get into the act, and more of his funds go to the cost of attending “all these terrible meetings.”
“I had to lay off two people out of a crew of eight,” he says. He finds the situation galling, he says, “because it’s the only world problem we have that we know how to fix.”
Gehrels uses a small, 74-year-old telescope, only 36 inches in diameter, on top of Arizona’s Kitt Peak to scan a narrow strip of the sky that is about the width of the moon. The telescope repeats the same 30-minute scan three times, and its computer isolates any object that has changed position between the scans. The course of any moving object can be determined through subsequent observations.
The program allows Gehrels to identify some asteroids that pass through the orbit of the Earth and thus could some day collide with this planet. A mile-wide asteroid could change weather patterns so drastically that life as we know it would end; a smaller asteroid the size of a football field could cause widespread destruction.
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He hasn’t found any that are on a collision course with Earth yet, but there could be thousands. Based on the historical record, if he could look long enough, he would find one heading our way. It is widely believed now that such an asteroid ended the reign of the dinosaurs 65 million years ago.
Chances are Gehrels would be able to detect an approaching asteroid several decades before it could hit, thus giving scientists time to do something about it.
Several ideas were advanced during a symposium last May at the Lawrence Livermore National Laboratory. Star Wars guru Lowell Wood argued that smaller asteroids measuring up to 200 meters in diameter could be destroyed by a series of hypervelocity projectiles strung together with a lattice of tungsten. The lattice would slice through the asteroid, cutting it into pieces so small they would burn up if they entered the Earth’s atmosphere. It has been dubbed the “kinetic-energy cookie cutter.”
Wood’s boss, the legendary Edward Teller, favors something called “cosmic exponential billiards.” Once it was determined that a large asteroid was on a collision course with Earth, Teller says, a rocket could be exploded near a smaller asteroid, sending it careening into the threatening chunk of rock. That would nudge the larger asteroid onto a different course, sending it speeding past Earth at a safe distance.
But Gehrels and others believe the best solution is much simpler. A rocket with a large warhead--nuclear if that much power is required--could be exploded alongside the approaching asteroid. The shock wave from the explosion could redirect the asteroid onto a safe course.
Gehrels is frustrated because he believes if we search diligently enough, we will find any approaching asteroids long enough in advance to allow us to try several ways of deflecting it.
If we don’t, and it arrives here without enough time for us to do anything, he sees another scenario.
“All the people will die,” he says.
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Lee Dye can be reached via e-mail at 72040.3515@compuserve.com.
