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The goal, originally outlined by NASA and mandated by the U.S. Congress, is designed to insure that space rocks in the vicinity of Earth's orbit are found and tracked. A large proportion of the focus aims to find object larger than one kilometre, an object of this size would cause global destruction if one were to hit Earth. The search is carried out by an international affiliation of groups, collectively called Spaceguard.
Currently there are no known asteroids are heading towards our home planet.. The asteroid with the best probability of an impact is 1950 DA, which has a 0ne in 300 chance of a collision in 2880. Although because of the time scale involved, it is expected that with more observations this probability will increase.
The search for Earth-threatening asteroids was described by three international experts at a public forum, David Morrison from NASA's Ames Research Center; Alan Harris of the Space Science Institute in Colorado, and Andrea Milani from the University Pisa, Italy. The forum expressed the concerns amongst asteroid scientists that when the current goal is reached, there will still be many unfound smaller objects that are easily capable of destroying a large city. Although it was also acknowledged that present technology is limited in its ability to find the thousands and perhaps millions of smaller asteroids that could potentially threaten the planet.
Bigger, better telescopes are on the drawing board for finding these smaller asteroids, and in the meantime images of the sky taken by current programs could be crucial to future attempts to find and track small asteroids using the new telescopes. Importantly, there are no large telescopes devoted to the task of hunting asteroids from the Southern Hemisphere. Global telescope observations over long time periods are essential in determining the exact trajectory and potential danger.
Generally the larger the asteroid the greater the potential danger, any object of one kilometre would cause a global environmental disaster smaller objects are still a danger to cities and regions. Normally when an asteroids is spotted its characteristics are assessed and it is given a Torino scale rating. The scale that determines the potential damage caused by such an impact. Normally an asteroids detection will alert astronomers world wide whose subsequent observations included in revised computations that, so far, have resulted in the impact risk being reduced.
The forum also discussed computer models that have helped predict orbits, atmospheric entry, impact processes and global atmospheric changes. The use of such, has enable scientist to predict numerous outcomes with numerous variables, but each help understand the potential threat of NEAs. The debate is expected to continue at the Australian Minor Planet later this month.
More info: space.com
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