NASA Cautions About Asteroid Detection
NASA Articles 5/21/12
By: Chris Capps
As the planet's first Annular Solar Eclipse in 18 years passes over us, NASA is still examining the findings of a recent survey of our immediate orbit. In the exploration, the space agency noted that there could be up to 4,700 potentially hazardous near Earth objects in our vicinity. Of these, only a fraction have been detected. The objects, zooming around our orbit in the space around the Earth could have very real consequences if they ever actually struck the planet, but how concerned are the experts?
NASA's announcement that somewhere in the neighborhood of 4,700 potentially hazardous objects are likely near Earth does come with one caveat - it could be far less, or more. The real number could be anywhere between 3,200 to 6,200 according to scientists depending on how accurate detection by the WISE (Wide-field Infrared Survey Explorer) Telescope has been. With asteroids being sometimes notoriously difficult to spot, this recent announcement is the latest as far as early detection systems go.
So how disastrous would a hit by one of these asteroids be? Actual damage caused by an asteroid falling would depend on a number of factors. First, there is the relative size of the object with those included in the analysis having a hazardous 330 feet or more. Objects of that size are often considered to be potentially hazardous if they ever actually struck the planet. Far larger objects, such as the 4581 Asclepius which passed a mere 6 hours behind Earth have been recorded in the past, which could have caused near apocalyptic collisions. Asclepius was a 300 meter monster asteroid with the potential explosive power of more than all the nuclear weapons ever detonated in every test the world over, including the Tsar bomb - the largest nuclear weapon ever designed. If it had struck the planet, it may have been an extinction level event for humanity.
So how much cause for alarm are these significantly smaller asteroids? For the most part, they seem to be on their own paths, not destined to intersect with Earth. Calculations are made with accuracy that is unparalleled, with most estimates proving to be accurate long after the objects pass for their next approach . Most objects approaching Earth are too small to detect by satellites such as the WISE system. And those that are large enough are usually seen long before they come near the planet.
With so many near Earth objects being tracked by satellites and telescopes, it's difficult to imagine anything slipping through the cracks and coming near unseen, but scientists caution that we have only detected somewhere between twenty and thirty percent of the potentially hazardous asteroids in our neighborhood. But if the ones we have detected are any indicator, an impact event in the near future with an object like them seems a safely remote possibility.