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article imageAstronomers say massive asteroid 2011 AG5 could hit Earth in 2040

By JohnThomas Didymus     Feb 29, 2012 in Science
Pasadena - NASA has identified a near-Earth object (NEO), an asteroid 460 feet (140 meter) wide, that may hit the Earth in 2040. Asteroid 2011 AG5, discovered in January 2011, is now considered "high risk" and could be in a catastrophic collision course with Earth.
JPL NASA reports astronomers are saying that more observations of the trajectory of the space rock are needed to confirm that it is on a direct collision course with the Earth; but they succeeded in placing the asteroid on the agenda of the 49th session of the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) held this month in Vienna.
Discovery News reports a UN Action Team on near-Earth objects noted the asteroid's close approach to the Earth and the possibility that it may impact directly on our planet in 2040.
Astronomers at the Mount Lemmon Surveys in Tucson, Arizona, discovered the asteroid in January 2011. reports that astronomers have a good idea of the size of the asteroid, but are uncertain of its mass and composition.
According to Detlef Koschny of the European Space Agency's Solar System Missions Divisions in Noordwijk, The Netherlands: "2011 AG5 is the object which currently has the highest chance of impacting the 2040. However, we have only observed it for about half an orbit, thus the confidence in these calculations is still not very high."
Koschny, according to, said: "In our Action Team 14 discussions, we thus concluded that it not necessarily can be called a 'real' threat. To do that, ideally, we should have at least one, if not two, full orbits observed."
Koschny said the Action Team recommended that the NEO Working Group of COPUOS use 2011 AG5 as a "desktop exercise" in preparation for future asteroid collisions with the Earth. "We are currently also in the process of making institutions like the European Southern Observatory aware of this object," Koschny said. "We hope to make the point that this object deserves the allocation of some special telescope time."
JPL NASA reports that Donald Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif., says asteroid 2011 AG5 has been assigned an impact probability of 1 in 625 for February 5, 2040. He said: "Fortunately, this object will be observable from the ground in the 2013-2016 interval."
Yeomans said that if the assessment of impact probability of the asteroid remains high after repeated observations of its trajectory in space, there would be time to mount a deflection mission to alter its course before the 2023 keyhole.
According to, a "keyhole" is a small region "in space near Earth through which a passing NEO's orbit may be perturbed due to gravitational effects, possibly placing it onto a path that would impact Earth."
The asteroid is expected to pass a keyhole on a close approach to Earth on February 2023. At this approach, the asteroid will come within 0.02 astronomical units (1.86 million miles or 2.99 million kilometers) of the Earth (1 astronomical unit is 93 million miles or 150 million km, the distance between Earth and the Sun).
Astronomers say the asteroid must pass this keyhole (62 miles or 100 km wide) and have its course deflected by gravitional pertubation to have a chance of hitting the Earth in 2040. Yeomans says what happens in 2023 (that is, whether or not 2011 AG5 passes the keyhole) will determine the impact threat in 2040.
ABC News reports scientists are already speculating on how a collision could be averted. According to ABC News, scientists may have to send a probe with thruster rockets or explosives to nudge the asteroid into a slightly different path.
Researchers are meanwhile calling for closer study of the asteroid's trajectory. Yeomans, according to JPL NASA, said: "In September 2013, we have the opportunity to make additional observations of 2011 AG5 when it comes within 91 million miles (147 million kilometers) of Earth. It will be an opportunity to observe this space rock and further refine its orbit. Because of the extreme rarity of an impact by a near-Earth asteroid of this size, I fully expect we will be able to significantly reduce or rule out entirely any impact probability for the foreseeable future."
JPL NASA reports even better observation will be possible in late 2015.
More about NASA, Asteroid, near earth objeccts, 2040
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