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Do We Need a Crash Effort to Thwart Killer Asteroids?

Astronomers’ recent announcement that an asteroid has about a 1-in-25 chance of smashing into the surface of Mars brought back the memory of those alarming headlines in 2002, when a 1,000-to-1,300-foot-long rock named 2001 YB5 hurtled toward Earth. What CNN labeled the "killer asteroid" turned out to miss our planet by 375,000 miles, about 1.5 times the distance between Earth and the moon. But by asteroid standards, that’s way too close for comfort.

Sure, sizeable asteroids don’t strike the Earth very often — on average, an object 1 kilometer (.6 miles) or larger hits every 500,000 years. But when they do, all hell usually breaks loose. Scientists believe an asteroid 6 miles in diameter struck the Yucatan peninsula 65 million years ago, releasing energy that was the equivalent of 100 million megatons of TNT and generating a planet-wide heat pulse so intense that according to one recent study, it probably killed off the dinosaurs in a matter of hours. In 1908, another asteroid probably caused the Tunguska Event in Siberia, a mysterious aerial explosion that generated enough force to level 80 million trees and cause an earthquake estimated at 5 on the Richter scale.

Nobody is sure how many potential killer asteroids are out there, but astronomers already have discovered more than 5,000 Near Earth Objects (NEOs) — that is, asteroids, comets and meteors whose orbits bring them within 124 million miles of Earth. About 900 of these have been classified as Potentially Hazardous Asteroids (PHAs), objects at least 500 feet in diameter that come within 46.5 million miles of our planet (about half the distance between Earth and the sun).

Even the least imposing PHAs have the potential to cause a devastating tsunami, while the bigger ones could wipe out an entire city and kill millions of people. (Imagine, for example, what would have happened if the Tunguska Event object had exploded over Moscow.) But it’s the exceedingly remote but nevertheless possible collision with a Yucatan Event-sized asteroid that really gives cause for concern, because it could wipe out the great majority, if not all, of the living creatures on Earth.

So if we’re threatened with the prospect of annihilation from the cosmos, what are we doing about it? If life were a Hollywood movie — say, the 1998 Hollywood disaster flick Armageddon — NASA simply would launch Bruce Willis and his intrepid team into space on a mission to land on the giant asteroid, drill an 800-foot-deep hole, drop in a nuclear bomb, and then remotely detonate it, cutting the PHA precisely in half so that both pieces narrowly miss Earth. (As the Bad Astronomy blog notes, splitting an asteroid in half might well cause one of the pieces to hit Earth with even greater velocity.) In reality, NASA isn’t doing much at this point beyond surveying space and attempting to identify and chart the NEOs and PHAs out there, a project for which the government has allocated a relatively minuscule $4.1 million a year. (NASA hopes to have that job 90 percent complete by 2020.) A 2007 NASA report to Congress only briefly touches upon possible killer-asteroid mitigation strategies. Instead of trying to split an asteroid into pieces, scientists have contemplated using the gravitational attraction of a giant spacecraft to pull the asteroid in a different direction, or using a giant mirror to focus solar energy on the asteroid’s surface and boil off material, creating thrust that would change its path.

In order to actually be able to do any of these things in the foreseeable future, however, we’d likely have to allocate many billions of dollars to an effort vastly more ambitious than the Manhattan Project or the Apollo program to put men on the moon. Developing effective asteroid-diverting technology might well divert resources and attention away from other important priorities, such as the efforts to mitigate global warming. On the other hand, if a killer asteroid strikes Earth, we might not be around to worry about climate change any more. So what do you think? Should we launch a crash program to deal with the threat of killer asteroids? Offer your opinion below.

Should U.S. Presidential Candidates Stake Out a Policy Position on UFOs?

In addition to the Iraq war, global warming and other important world issues, voters and the news media have been pressing 2008 presidential candidates for their positions on extraterrestrial matters as well. Here’s a video clip of former New York mayor and GOP presidential hopeful Rudy Giuliani at a town meeting in New Hampshire, being quizzed about how he would respond to an attack on the U.S. by space aliens. (“Of all the things that can happen in this world, we'll be prepared for that, yes we will. We'll be prepared for anything that happens," was Hizzoner’s response.) According to this Fort Worth Star-Telegram story, New Mexico Gov. and Democratic contender Bill Richardson revealed to a questioner at a Texas event that as a member of Congress, he had asked for access to U.S. Department of Defense files on the infamous Roswell UFO incident, but was rebuffed because the information was classified. (“That ticked me off,” he added.) And in the most recent Democratic presidential debate in Philadelphia, Ohio congressman Dennis Kucinich confirmed a published claim that he had once seen a gigantic triangular craft hovering silently for 10 minutes over the home of actress-turned-New Age maven Shirley MacLaine.  “I did," Kucinich admitted. "It was an unidentified flying object, OK? It's like, it's unidentified; I saw something."  As this article from Rawstory.com recounts, Kucinich subsequently contended — not quite correctly — that more Americans have seen UFOs  than approve of President Bush’s job performance. (According to a 2005 Harris Interactive poll, 34 percent of Americans believe in UFOs, roughly the same number who support Bush.)

The Democratic front-runner, New York Sen. Hillary Clinton, is probably a bit too cautious to speak out about the possibility of alien spacecraft visiting Earth. Nevertheless, Huffington Post blogger Sam Stein reports that Stephen Bassett, chief lobbyist for the Extraterrestrial Phenomena Political Action Committee, is leaning toward supporting the former first lady, in part because Clinton adviser (and her husband’s former chief of staff) John Podesta has advocated declassification and release of Defense Department files on a purported UFO sighting in Kecksburg, Pa., in 1965. (“It is time for the government to declassify records that are more than 25 years old and to provide scientists with data that will assist in determining the real nature of this phenomenon," Podesta told CNN in 2002.)

Some might consider the UFO issue a bit too, well, wacky for a potential president to even bother thinking about. But others, such as Richardson, argue that it’s time for full disclosure of whatever the government knows about UFO incidents, if only in the interest of transparency and restoring trust that has been eroded by the Bush administration’s penchant for secrecy. Give us your opinion here.