On 4th February 2011, an asteroid approached Earth for a fly-by. Asteroid 2011 CQ1 was discovered by the Catalina Sky Survey on 4th February and made a record close Earth approach 14 hours later. CQ1 scraped past the Earth less than 5500 km from the surface. Although the object was small, only about one metre in diameter, it is the closest non-impacting object to date and focuses our attention to the vulnerability of system Earth.
Those who search for near Earth objects (NEOs), estimate there have been over 1000 NEOs over 1km in diameter. With smaller NEOs included, the NEODys-list of observed objects counts more than 7700 flying rocks.
The scientific interest in comets and asteroids is due to their status as the relatively unchanged remnant debris from the Solar System’s formation some 4.6 billion years ago. As the primitive, leftover building blocks, comets and asteroids offer clues to the chemical mixture from which the planets formed – a unique insight into the earliest history of our Solar System.
Over the decades, the search for NEOs at programmes like NASA’s NEOP or the Spaceguard Cenral Node hosted by ESA used an easy method. Night sky pictures, taken several minutes apart, were compared with each other. Stars and galaxies recorded on these films were located in the same relative position on both images. As NEOs are travelling objects, they would be in slightly different positions on each photograph while the background stars and galaxies remain constant. Today’s digital photography allows us to compare several pictures of the same sky with a unmatched spatial resolution enabling fast moving objects to be spotted.
Over a 30 year period, there is a 1-in-5500 chance that a 1km asteroid will hit our planet. Such an impact could take out a region as wide as Greater London.
Despite the potential devastation a collision would have, one has to ask if all the time, manpower, and money to find NEOs is worth it? What if we find a kilometre object heading for the Earth? Is there a strategy to deflect or destroy an asteroid before it would crash into Earth? Modern asteroid mitigation strategies include the nuclear pulse propulsion or the use of focused solar energy – and there are a lot of other proposals in discussion internationally.
However, there is still one question unanswered – how will mankind react if a potentially hazardous object is found to be on a collision course for Earth? There is no plan on how communicate such a risk or how to prepare residents for evacuation. In 2000 the British National Space Centre published its Report of the Task Force on potentially hazardous near Earth objects, but the recommendations did not take in consideration the social impact. If there was a global consensus on how to react to a NEO-hazard, there are still a bunch of decisions no-one is prepared to make.
By not hitting Earth, CQ1 reminded us that there has to be a political strategy, not only for funding the search for NEOs, but also for research and development of deflection methods and communication strategies. The EU, the UN and all governments are invited to take the leading role on finding a solution.
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