Published on November 8th, 20130
How big is the danger of an asteroid impact? Much higher than previously thought, scientists warn!
When an asteroid only 20 meters in diameter exploded over Russian city Chelyabinsk, injuring over 1,000 people, astronomers said it was a rare event. But recently, other scientists have suggested after some studies, that the Earth is actually more vulnerable to the threat of asteroids than previously thought.
In two articles published in the journal Nature, researchers estimate that such events could happen relatively often - every 10 or 20 years.
These calculations will help organize the defense of the planet, identifying hazardous asteroids and destroying them if need, however more research is needed to develop the necessary technologies.
A UN committee also studied the problem, and next month the UN General Assembly could adopt two of its recommendations, establishing an international asteroids warning network, designed to help the sharing of relevant information between several countries, also UN may require space agencies of different countries to develop a plan of cooperation for the development of technologies to divert asteroids.
Research has so far led to the identification of 95% of large near-Earth asteroids, those who have at least 1 km in diameter, and none of them will collide with the Earth in the near future.
But some scientists warn that a 1 km asteroid is not simply ” dangerous” , but can mean the right end of human civilization, Edward T. Lu , former NASA astronaut and director of the B612 Foundation, a private -initiative which aims to launch a space telescope designed to detect smaller asteroids , smaller than 1 km but which can produce large-scale disasters.
An asteroid of 2-3 times bigger than that of Chelyabinsk fell in Siberia in 1908 and is estimated to have released an amount of energy equivalent to 5 to 15 million tons of TNT, pulverizing millions of trees.
A telescope proposed by the B612, which will be called Sentinel, is expected to detect asteroids up to 90 meters in diameter, although it may find many more smaller ones. Dr. Lu says that this mission will cost $ 450 million to operate for a decade.
A 90 m diameter asteroid would be equivalent to 150 million tons of TNT and could kill 50 million people, or would have a devastating impact on the global economy for a century or two, says Dr. Lu.
According to astronomical discoveries, 10-20 % of asteroids near Earth have this size.
But smaller asteroids could be detected by other systems: Astronomers at the University of Hawaii now developing telescopes that will scan the sky in search of bright dots moving quickly and may indicate forthcoming fall of small asteroids, as was the one in Chelyabinsk, will be operational in 2015.
Source: New York Times