TCS Daily

Preparing for the Worst

By Glenn Harlan Reynolds - March 10, 2004 12:00 AM

Quite some time ago, I wrote about scientists' questions on whether to deliver bad news. The news in question had to do with a potential life-ending asteroid strike. Perhaps, I suggested, it might be best not to deliver that news, if things were bad enough that nothing could be done. I also noted that this was an active question within the astronomical community.

It became an even more active question recently, when just such an asteroid strike appeared to be likely. As one account put it:

It could have been a scene from a B-grade doomsday movie: Some of America's most respected astronomers weighed a call to top NASA authorities -- and ultimately the White House -- to report that a large asteroid was streaking toward Earth and could hit within days. The call was never made, but the scene was real -- played out during what one veteran researcher called a "nine-hour crisis" on the eve of President George W. Bush's Jan. 14 announcement that he was restarting the United States' manned space program to return to the moon and then venture on to Mars.

Astronomers' information showed -- wrongly, it turned out -- that a 30-metre-wide asteroid had as much as a 40 per cent chance of crashing somewhere in the Northern Hemisphere with the force of a one-megaton bomb.
In the event, the asteroid was much larger than astronomers first thought -- about 500 metres wide -- but it safely cleared Earth by at least 12 million kilometres, about 32 times the distance between Earth and the moon.

That's a good thing, but it underscored several problems. The first was that, although there has been some discussion of the topic, there still isn't much of a plan in place for what to do if a dangerous asteroid strike seems imminent. It's possible that efforts to protect populations -- even just getting people away from coasts or lowlying areas -- might save a lot of lives in such an event, but that sort of thing could use some further analysis. The planning for this scenario hasn't been done, and it should be. It's also unclear who would put such a plan into effect even if it existed. As another report notes:

A clear and present danger for those studying planetary defense is the lack of any chain-of-command to take on the duties of dealing with the prospect of disruptive collisions from asteroids and comets. This "who do you call?" factor deserves immediate attention, said Michael Belton of Belton Space Exploration Initiatives in Tucson, Arizona.

The second problem was that we don't really have much of a network in place to look for this kind of threat. Cloudy weather made it hard to verify the initial threat assessment, and it was an amateur astronomer in Colorado who made the essential observation demonstrating that the asteroid in question wasn't a threat. NASA looks for really big objects as part of its SpaceGuard program, but the program is limited in scope.

The good news here is that we may get some more eyeballs on the problem: The House of Representatives has passed legislation designed to encourage amateur astronomers to look for asteroids that might threaten Earth, by making awards of up to $3000 each. With luck, this bill will become law, bringing the "pack, not a herd" approach to this issue. Fortunately, Britain appears to be looking at addressing this issue as well.

The threat posed by near earth asteroids is hard to quantify precisely. The risk of a major strike in our lifetimes is probably small; the risk of one sooner or later approaches certainty. Should a major strike take place, it would likely mean a major setback to civilization, coupled with millions -- perhaps billions -- of deaths. That's worth doing something about, even if the likelihood appears small.

Unfortunately, all we can do at the moment is to look for threats (the legislation in question, HR 912, is a good start), and try to mitigate them if they appear (more planning on mitigation is needed). Prevention is iffy: Trying to divert an asteroid, even with years of lead time, would be right at the edge of our technological and industrial ability. Despite movies like Armageddon, the prospects for actually preventing such a strike appear poor. (Go here and follow the links for more information on these issues.)

The good news is that if we move ahead with more ambitious space programs, we'll be in a much better position to deal with such threats within a couple of decades, meaning that our present window of vulnerability doesn't have to last. And beyond that, the eventual settlement of outer space will disperse humanity sufficiently that no single disaster can wipe us out. As I've written before, the earth is too fragile a basket to hold all of our eggs. By moving life and civilization off the planet, we'll address this threat, and others known and unknown.

Reason enough for space settlement all by itself? Probably so.

Glenn Reynolds recently wrote for TCS about the President's Council on Bioethics.


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