The asteroid Apophis may be more likely to hit Earth in 2068 than previously thought

David Tholen, an astronomer at the University of Hawaii, recently reported on the status of the asteroid Apophis during a virtual meeting of the American Astronomical Society’s Division for Planetary Sciences. During his presentation, he outlined the research he and his team conducted regarding the asteroid’s path and the likelihood of it hitting Earth.

The asteroid Apophis was first identified by astronomers in 2004. Soon after, researchers worked out its orbital path and found that the 340-meter-wide asteroid would pass close to Earth in 2029, 2036 and again in 2068. Further studies showed that there was little chance of the asteroid hitting Earth; therefore, it was discounted as a threat. More recently, Tholen and his team noted that previous researchers had not taken into account the Yarkovsky effect whereby the sun’s rays strike one side of an asteroid. As heat radiates away from the asteroid, a small amount of energy pushes back against the asteroid, forcing it to spin slightly. Tholen and his team calculated that the Yarkovsky effect is pushing Apophis to one side enough to force it to move about 170 meters per year. They later applied that little bit of knowledge to mathematics that describes Apophis’ orbit and found that drift is changing the asteroid’s course in a way that will bring it closer to Earth. He notes that so far there are no indications that the asteroid will hit Earth in 2029 and 2036, but 2068 could be another matter. He suggests that astronomers will need to keep an eye on Apophis as his rendezvous date approaches.

With the news of a possible threat from Apophis, others pointed out that the human race has made great strides in protecting the planet from asteroid attacks. NASA’s DART mission, for example, scheduled for 2022, will involve sending a spacecraft to an asteroid called Didymos and using it to alter the path of Dimorphos, one of its moons. Tholen noted during his speech that the study of Apophis when it passes in 2029 should give scientists a much better idea of ​​whether or not it poses a real threat in 2068.

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