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NASA: Massive asteroid will not impact Earth in 2040

NASA has some good news for all of us living here on Earth: Don’t expect an asteroid impact in 2040.

The U.S.-based space agency announced Friday that a new analysis of the 460-foot space rock — known as 2011 AG5 — finds that it will not impact Earth in 2040.

“An analysis of the new data conducted by NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory … shows that the risk of collision in 2040 has been eliminated,” NASA said Friday in a written statement.

“The updated trajectory of 2011 AG5 is not significantly different, but the new observations have reduced the orbit uncertainties by more than a factor of 60, meaning that Earth’s position in February 2040 no longer falls within the range of possible future paths for the asteroid,” officials from the Gemini Observatory added.

The space agency had warned of a possible impact, putting the chances at around one in 500. The newly revised projection now places the asteroid around 550,000 miles near Earth — over twice the distance to the moon — in February 2040.

Had the asteroid, which had a diameter roughly equal to a pair of football fields, collided with Earth, it would have released approximately 100 megatons worth of energy — several thousand times more powerful than the pair of atomic bombs dropped during World War II, researchers said.

The results of the latest data set were widely expected. Earlier in 2012, NASA’s Near-Earth Object (NEO) Program Office conducted a contingency deflection analysis for the 2040 potential impact of 2011 AG5. Among the findings was that any new observations either in 2012 or in 2013, when the object will be much easier to observe, had a 95 percent likelihood of eliminating the hazard posed by 2011 AG5. If the potential for impact had been confirmed the impact odds could have risen as high as 1 in 10, but the May 2012 study found that scenario to be unlikely.

Among the factors making AG5 particularly dangerous related to the inability of astronomers to capture an accurate picture of its rotation. The team of astronomers discovered the asteroid is elongated, so that as it rotates, its brightness changes. Because astronomers did not know the asteroid’s rotation period, they could not know when it would wax and wane, making it difficult to determine its exact size and orbit.

“As it turns out, the asteroid is highly variable in brightness, which is probably why we were unable to make definitive observations on the smaller telescope,” said  David Tholen, an astronomer at the University of Hawaii Institute for Astronomy.

According NASA, the experience gained by studying the object and demonstrates that astronomers, using NASA facilities, are well poised to detect and predict the trajectories of Earth-threatening asteroids in the future.

The announcement comes as NASA has expanded its NEO organization with the hopes of being able to better predict asteroid impacts on Earth.  The first near-Earth object found, called Eros, was not discovered until 1898. Since then, telescope surveys have revealed several thousand near-Earth objects, many of which are capable of an atomic-bombs worth of destruction.

According to NASA, the space agency detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The NEOOP, commonly called “Spaceguard,” discovers these objects, characterizes a subset of them, and plots their orbits to determine if any could be potentially hazardous to our planet.

The data for this study are being published by the Minor Planet Center in Cambridge, Massachusetts.