Asteroid Apophis Might Be More Likely To Hit Earth In 2068

A report on the status of asteroid Apophis has been recently presented during a virtual meeting of the American Astronomical Society’s Division for Planetary Sciences. In this report, David Tholen, an astronomer at the University of Hawaii outlined his research related to the path of the asteroid and the likelihood that it will strike Earth.

Apophis or 99942 Apophis is a near-Earth asteroid with a diameter of 370 metres that was discovered on June 19, 2004. It was predicted that this asteroid would pass near to the Earth in 2029, 2036 and again in 2068. Though initial calculations showed that there was a high probability of this asteroid striking earth, later studies ruled out this threat.

But recently, Tholen with his team pointed out that earlier studies did not account for the Yarkovsky effect by which rays from the sun strike one side of an asteroid.

Yarkovsky Effect
The Yarkovsky effect is about a small but significant force that affects the orbital motion of meteoroids and asteroids smaller than 30-40 kilometres in diameter. It is caused by sunlight; when these bodies heat up in the Sun, they eventually re-radiate the energy away as heat, which in turn creates a tiny thrust.

The team calculated that the Yarkovsky effect is pushing Apophis to one side enough to force it to drift by approximately 170 meters a year. After putting in some math and calculations, the team found out that this effect will bring Apophis even closer to earth. Though there is no indication that the asteroid will strike the Earth in 2029 and 2036, but 2068 might be another matter. Tholen suggests that astronomers will have to keep an eye on Apophis as its rendezvous date approaches.

Tholen noted during his talk that study of Apophis when it passes by in 2029 should give scientists a much better idea of whether or not it poses an actual threat in 2068.