Seti aff •seti neg •Asteroids Aff
Article: Asteroids Not A Threat
Download 2.75 Mb.
|
Article: Asteroids Not A ThreatWired Magazine: The Sky is Falling? No Sweat. January 18th, 2002. Steven Pravdo hunts asteroids, but he says he hardly ever thinks about the fact that, any day now, he might discover a rock that could collide with Earth, perhaps causing "one of the worst disasters in human history." Those were Pravdo's alarming words to the Associated Press last week. The project manager of NASA's Near Earth Asteroid Tracking program was describing what might have happened if asteroid 2001 YB5, which passed by Earth on Monday at the relatively close distance of 500,000 miles, had instead smacked into the planet. Even though the 1,000-foot-long rock was discovered just 10 days before it sneaked by, Pravdo said YB5 didn't merit the attention it received. "What happened with that was a reporter from the Associated Press. It must have been their beat to look up these things; they saw it was close and thought it was a story. But in this case it was known to be very close, but it was also known that it wouldn't hit anything; it wasn't a danger at all," Pravdo said Thursday. This worst-calamity sort of story periodically crops up in Pravdo's job. Three years ago, for example, he and his colleagues found themselves explaining to salivating reporters that, contrary to earlier asteroid theories, the world would not end in a collision in 2028. But there are more such explanations to make these days because the asteroid hunters are finding more hurtling rocks than ever. During the past 10 years, and especially since 1998, advances in technology and increased government funding have significantly improved the rate at which near-Earth objects are detected. "The current estimate -- and this is just an estimate -- is that there are about 1,200 of these asteroids that come near the Earth and are larger than 1 kilometer in size," Pravdo said. "By 2008, we're trying to find all of these." As of Wednesday, scientists had discovered 564 near-Earth objects; 471 have been found since 1990. The process of discovering one of these rocks is akin to looking for a very tiny needle in a stadium-sized haystack that -- just to keep things interesting -- is very far away. Every night, Pravdo and his team aim their powerful electronic cameras at a small patch of the sky. They take three different pictures of the same spot, each one at a different time. Then the three images are overlaid over each other, and the team uses a computer to see whether any of the objects appear to have moved over time. These moving objects are possible asteroids. After one of these is discovered, Pravdo said, it takes several days to determine the orbit of the object in order to determine whether it poses any risk to Earth. During these few days, Pravdo says, he never worries that anything calamitous will happen. "It's like when you buy a lottery ticket, are you ever excited that it's going to win?" he asked, by way of explaining how he keeps his cool. "That's what the odds are like here." Actually, though, the odds of getting hit by an asteroid are actually better than winning most state lotteries. Since so many people could perish in a catastrophic asteroid collision, even if such a crash almost never occurs, it turns out that the risk of death-by-interstellar-rock is just about equal to the risk of dying in an airline accident -- about 1 in 20,000. And currently, Pravdo said, there might not be too much we could do to avert such a disaster. If the YB5 asteroid had been speeding toward Earth and the planet had only 10 days notice, the most humanity could have done, Pravdo said, would have been "to find out what part of the Earth would be hit and then send condolence notes to them." "A longer lead time would mean that the 'responsible parties' of the Earth could set up a program to institute some technological policy that could try to move the object away," he added, referring to Hollywood’s famous technique of shooing away the asteroid with a nuclear weapon. Ever since Armageddon and Deep Impact awakened people to the danger of asteroids three years ago, there is increased worry about a collision each time an asteroid passes nearby. This week on Usenet, for example, it was possible to find people advocating the creation of Martian colonies as a way to make sure the human species survives after a big crash. Some people took issue with this suggestion. One reader of the sci.skeptic newsgroup warned that "a Mars colony would produce a small carbon copy of our Earth habitat but on rather less promising ground," and instead suggested that programs such as Pravdo's be expanded and that governments begin to seriously think about safe asteroid deflection techniques. Asteroid deflection is a well-studied topic, Pravdo said, but the various suggestions made by scientists are not generally known to the rest of the public. In addition to nuclear weapons, there may also be a variety of other ways to prevent disaster. For example, an asteroid expert told Space.com a couple years ago that "attaching a giant solar sail to the asteroid" might guide it away, and using "a giant parabolic mirror to concentrate the sun's rays and vaporize rock on the surface of the asteroid" could also do the trick. For obvious reasons, these ideas are difficult to test. "Even though some technology exists, it would have to be applied in a different way, and we wouldn't know if it would work," Pravdo said. Of course, these days, the fear of an asteroid extinction is not the first thing that comes to mind. "Right now, (humans) are the greatest threat to the survival of the human species," wrote J. Scott Miller in a discussion on Usenet's sci.space.science newsgroup. "We have built enough nuclear weapons to do the job, we have developed the biological and chemical capabilities to do the job. So, let's not point out there for possible extinction until we control down here." "Terrorists running willy-nilly over this globe present a much bigger threat (than asteroids)," he added in his message, which was penned in 1998. Directory: wp-content -> uploads -> 2011 2011 -> Voices of the Old Sea Norman Lewis 2011 -> Malevil Robert Merle 2011 -> The Elephant Keeper’s Children Peter Hoeg 2011 -> Jv packet •Mars Colonization Affirmative •Mars Colonization Negative 2011 -> Registration Form (Rev. 8-86) omb no. 1024-0018 2011 -> All America Looks Up to Virginia;” Virginia and the Declaration of Independence 2011 -> Rao bulletin 2011 -> Christopher Columbus was born between 25 August and 31 October 1451 in 2011 -> The Battle of Frenchtown (1855), Washington Territory: the Political and Demographic Context rev 9/4/11 2011 -> The harmony society Download 2.75 Mb. Share with your friends:
|