Astrobiology Magazine contacted Dr. Donald K. Yeomans, Manager of the NASA Near Earth Object Program Office at the Jet Propulsion Laboratory with some additional questions:
Astrobiology Magazine: How much damage would QE2 cause if it struck a city? How does the damage compare to the recent meteor that struck Russia?
Don Yeomans: 2008 QE2, at about 3 km in extent, is one of the larger near-Earth asteroids and in the very unlikely event that an object this size should hit the Earth it would do far more damage than taking out a city (assuming it hit in a populated area of the Earth). It would cause serious global problems and possibly an extinction event. I don't like the term "city killers" but an object of about 30 meters would be expected to destroy a city-sized region if it were to hit Earth at the right place. There are millions of 30 meter and larger objects in near-Earth space.
There is no comparison between a hit by a 3 km sized object and one the size of the object that hit the Earth's atmosphere over Chelyabinsk (about 20 meters). The Chelyabinsk object created an impact energy equivalent to 440 kilotons of TNT explosives while a 3 km asteroid hit would be expectd to create an impact energy of about 2 million megatons of equivalent energy. The 3 km object's impact energy would be 4.5 million times larger than the Chelyabinsk event. Having said that, there are only about 1000 near-Earth asteroids larger than one kilometer and 95% of them have been found. None represent a threat to Earth in the foreseeable future.
AM: The asteroid has carbon and amino acids. Is this typical for asteroids that would have struck the early Earth? >How important would such asteroid impacts have been for the development of life on Earth?
Yeomans: 2008 QE2 is a C-type asteroid and would be expected to contain carbon-based materials and amino acids. The amino acids are inferred because meteorites that are thought to arrive from C-type asteroids have been found to contain amino acids. I think it is fair to say that an early bombardment of the Earth by comets and asteroids laid down a veneer of carbon-based organics and water, with the water coming from cometary ices or the ices (or hydrated minerals) in asteroids.
AM: Would binary asteroids such as QE 2 be more difficult to deflect from than single asteroids?
Yeomans: Deflecting a binary asteroid would not be more difficult than deflecting a solitary object. Just gently deflect the primary and the secondary will follow along.