AN ACTUAL WORTHWHILE GOAL FOR NASA:

Two decades ago, President Ronald Reagan memorably asked what the United States could do to stop a nuclear missile hurtling toward an American city, and was memorably told by an Air Force general, "Sir, we could do absolutely nothing." Aghast, Reagan set in motion a series of technology projects that, while plagued by snafus, may soon grant America at least some protection from nuclear destruction. Reagan's instinct--that it was irresponsible for government to do nothing about a threat to millions of lives--was the right one.

A few weeks ago, researchers at the Harvard-Smithsonian Center for Astrophysics briefly believed that an asteroid packing the power of a one-megaton nuclear bomb was days away from striking North America. They turned out to be wrong, needless to say. Had they been right and the president informed that a killer rock from space was approaching, when he asked what could be done, he would have been told, "Sir, we can do absolutely nothing."

NASA has been floundering around without a vision; recently George W. Bush proposed, then almost immediately dropped, a preposterous Moon base-Mars trip just to think of a way to spend NASA dollars. At the same time our world has no security of any kind against rocks and comets falling from the heavens--a small but very real risk to kill huge numbers of people. Why not put NASA on this problem and give the space agency a meaningful task?

First, the reasons to take asteroids and comets seriously: The gargantuan Chicxulub meteorite, which left a 186-mile-long depression at the tip of the Yucatan Peninsula, probably killed off the dinosaurs. But that was 65 million years ago. Big rocks from space only fell in the primordial past, right?

In 1908, an object 250 feet across hit Tunguska, Siberia, flattening trees for 1,000 square miles and detonating with a force estimated at 10 megatons, or 700 times the power of the Hiroshima blast. Had the Tunguska rock hit Moscow or Tokyo, those cities would have been seared out of existence. In 1490, an estimated 10,000 people were killed when a mid-sized meteorite hit China. In the year 535, a series of mid-sized meteorite strikes around the globe kicked enough dust and debris into the atmosphere to cause several years of cruel winters, helping push Europe into the Dark Ages. Ten thousand years ago, just as modern Homo sapiens were making the first attempts at controlled agriculture, something enormous struck the Argentine Pampas, obliterating a significant chunk of the South American ecology with a force thought to be 18,000 times that of the Hiroshima bomb.

Asteroids and comets are hardly just a danger from the primordial; loads of them drift through the solar system to this day. Estimates by the Space Science Institute of Boulder, Colorado, suggest that perhaps 500,000 asteroids roughly the size of the Tunguska rock wander near Earth's orbit. Much spookier are asteroids big enough to cause a Chicxulub-class strike. Roughly 1,000 such space rocks are believed to exist in Earth's general area, some capable of killing many millions when they strike, then plunging the planet into a years-long freeze while showering the globe with doomsday rain as corrosive as battery acid. Asteroids large enough to cause years of deep-freeze and many species extinctions are estimated to strike Earth at least every few hundred thousand years.

Yesterday the grandly named Planetary Defense Conference, a first-of-its-kind meeting of technical experts, ended in California. Experts discussed current programs by NASA and by private observatories to locate and chart the largest "near-Earth objects." Such programs, while useful, are far from comprehensive; the exact orbits of asteroids are hard to forecast, leading to a few celebrated false alarms. And at any rate, if NASA or an astronomer did spot a killer rock headed straight toward Earth, there is absolutely nothing that could be done.

Should humanity simply assume its luck will hold? Many don't think so. As Nathan Myhrvold, the chief technology officer at Microsoft, has written, "Most estimates of the mortality risk posed by asteroid impacts put it at about the same risk as flying in a commercial airliner. However, you have to remember that this is like the entire human race riding the plane." The chance of a deadly strike from space is, in any given year, extremely small. But that's no guarantee that a rock from space won't fall tomorrow and kill millions--after all, the chance of winning the Powerball is extremely small, and someone just won it.

A project to design and build technology to deflect asteroids or comets headed toward Earth would take years and cost billions of dollars. But then it's not exactly as if NASA has anything more pressing to do! The Moon and Mars will always be there; they can be explored at leisure, if some future engineering breakthrough renders space flight affordable. Protecting Earth from strikes from space seems a much more immediate and substantial mission for the space agency than building dormitories on Mars.

Of course, if NASA did invest years and billions in an asteroid defense, the system might never be used, causing detractors to rail that the money had been "wasted." But the ideal outcome for all forms of insurance is that your money is wasted. Every time I send in a payment on my life insurance, I think, "I hope this money is completely wasted." The same would be true for space-rocks protection.

If Easterbrook forgets his lithium next November, he might accidently vote for Bush....

"....President Ronald Reagan memorably asked what the United States could do to stop a nuclear missile hurtling toward an American city, and was memorably told by an Air Force general, "Sir, we could do absolutely nothing." Aghast, Reagan set in motion a series of technology projects that, while plagued by snafus, may soon grant America at least some protection from nuclear destruction."

The moments of lucidity, such as the one above and his very favorable coverage of The CLear Skies Act, make me think this guy could one day be brought over to the Light Side of The Force.

An important point that Easterbrook left out is that if a multi-megaton space strike did occur with little or no warning, there is a good chance that humans will finish the job. Maybe we should take comfort in Russia's failed war game launches but I wouldn't bet the farm on it. Besides, why worry ... we have Bruce Willis don't we?

BS. Over 75% of the planet is water creating a tsunami to inundate California beach houses.

No big loss.

BUMP

A missile defense system could perhaps one day down the line double as an asteroid/comet defense system. Dual-use technology helping to kill two birds with one stone.

A missile defense system could perhaps one day down the line double as an asteroid/comet defense system. Dual-use technology helping to kill two birds with one stone.

The technology that we are developing is Hit-to-Kill. Given the mass & velocity ratios of a (dense) ferrite meteor and the kill vehicle on one hand, and the close proximity of intercept, I rather doubt that we could change the trajectory all that much. And given that the result would be more uncertain than the projected impact zone, I don't know that it would even be worth attempting.

Now if we could put a nuke warhead on the Kill Vehicle we might have a shot pulverizing the meteor or at least we could seriously deflect it.

There is a space rock incoming, there is a 98% chance it will hit in the street in front of your house: There is a missile incoming, there is a 98% chance it will hit in the street in front of your house: Stop the rock! But for God's sake let the missile come on it! No one must think we have a missile defense.

I think we should be in the business of stopping both. I got the impression that Greg did to. That's why I figured his mood had swung in a more positive direction.

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