August 18, 2011 by staff
An asteroid 6 miles wide hit the coast of present-day Mexico 65 million years of ecological changes brought about wiped out the dinosaurs. Inevitably, an earth-shattering piece of space debris will strike again.
However, there are so many earthly concerns that a cosmic, in a given moment is infinitely small do not gather much attention – or public funding. Several scientists who study asteroid hazards agree: humanity probably will not start preparing their planetary defenses until we know the danger is real.
Is it too late?
It depends. “Human beings can solve the technical problems that lay ahead of us,” said Daniel Durda, a planetary scientist at Southwest Research Institute in Boulder, Colorado, and an expert on asteroid collisions. “It is the social and political struggle.” Rusty Schweickart, former NASA astronaut and a founding member of the B612 Foundation, a nonprofit organization dedicated to protecting Earth from asteroid impacts, agreed: “The geopolitical realities are daunting technical issues are easy by comparison.”
Although we know very little about the composition of asteroids – the information needed to determine their masses, and learn how to lose your way – we know that most of the large rocks, about who they really are. NASA Spaceguard Survey tracks the paths of all near-Earth asteroids (NEA) in the neighborhood of the Earth that are larger than 1 kilometer (0.6 mile) in diameter.
Knowing the location of an asteroid is a step in determining whether it is a crash course on Earth, and fortunately, none of the big a threat at this time. If one of these known asteroids were found to have a higher percent chance that a strike on Earth, astronomers contained at least a decade earlier.
“A major impact of some 1 km wide – is a serious enough situation could motivate people to take this seriously,” Durda said. According to Clark Chapman, another scientist at the Southwest Research Institute, the international community is likely to come together and plan a mission to deflect the asteroid’s trajectory. “This would probably require matching its orbit with a series of spacecraft equipped with bombs,” said Chapman. Obtaining the deflection mission of the land cost of about + 10 billion.
Although we have prepared all the technology, however, we do know how to build nukes, and we have successfully sent the spacecraft and asteroids. “Ten years out, given the technology needed to make a detour, I could respond in time,” Durda said Maikelnai, a sister site to SPACE.com.
David Morrison, interim director of the NASA Lunar Science Institute and an expert on impact risks, think you might need more time. He believes that it takes two missions to deflect an asteroid. The first serious encounter with the asteroid and determine what is actually the second, which are specially adapted to asteroids based on the first mission, to throw him off course. “A decade would be the minimum, but that would mean sending the deflection mission before had marked the target, which would be a bit risky. Twenty years is more realistic minimum,” Morrison wrote in an email.
Schweickart says 15 years warning of an impact is it a safe bet. Along with the time it takes to assemble a launch vehicle, launch, fly and meet with an asteroid, is also necessary “long enough for their own diversion to accumulate sufficient changes in [asteroid] orbit to miss the impact with Earth. Posterior deviation require anywhere from say 3 to 10 years for the change of orbit. ”
There are dangers with asteroids below the threshold of 1 kilometer, however.
“Anything over 300 to 400 meters (983 to 1.312 feet) in diameter can cause damage on a continental scale,” said Stephen Wolters, a Caltech researcher who studies asteroids near Earth at the Jet Propulsion Laboratory of NASA.
NASA has begun tracking and tracing of small asteroids, but there are thousands who remain at large. If one of these were on course to strike Earth, sky surveys will give us no more than one month’s notice. In that case, said Morrison, the deviation is probably not an option. Instead, “more responsive to the way we handle hurricane warnings,” to evacuate people from the area most likely to be achieved.
In the end we will track all asteroids larger than 200 meters (656 feet) wide. The day the scientists realize that medium-sized rocks have a chance of beating us, and we have enough time to do something about serious political conflicts likely will occur, experts say.
“If we had an early warning on a smaller scale asteroid, 200 meters wide, I think it is in the area that would be much more likely to discuss the possibilities and not really respond to it,” said Durda.
This type of collision of an asteroid probably would not cause a global catastrophe, only a national or continental, he said. This means you may not all countries that care to lend a hand to deflect it, and others may be against any action, if you put them at greater risk.
“The big challenge will be the international implications of where they occur, so the range is – usually the orbital uncertainty that there is a track across the Earth where it is most likely to hit,” he said. “So if you decide to divert the asteroid, where they move through the track surface of the Earth before moving off the surface? Now you are taking an act of God and turn it into an act of litigation, which has moved the point of potential impact on countries that had been safe. ”
He continued: “It is these issues as it will lead to all sorts of discussion and argument and delay inherent to take any physical action.”
Given the orbital uncertainty, another question is how likely being an impact before deciding to act. “The economies of the world can not afford to protect against all risks of low probability,” said Chapman. A 1-in-1, 000 the possibility of a collision, for example, will probably be ignored, and according to Schweickart, already. “There are some near-Earth objects with the impact probability greater than 1 in 1000 and not the least excited,” he wrote in an email. A NEA 130 meters wide, called 2009FD, for example, has a 1 in 435 chance of impacting Earth in the year 2185.
“For [the case] to 500 meters wide, near-Earth asteroids, a probability of more than 1 percent, I would take the threat very seriously,” wrote Morrison. “Below that I do not know.” [
There is a form of cosmic debris that no amount of international cooperation can do much about it.
“There is always a possibility of a long-period comet that comes from nothing and gives almost no warning,” said Wolters. Not only do the organs come from the outer solar system where we cannot see them, “these comets may come from high-inclination orbits that we are not looking for things. You may notice only a few months.”
Fortunately, experts believe that long-period comets represent only 1 percent of all space rocks pass through Earth. “The good news is that they are only a small fraction of global risk,” Durda said.
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