January 8th, 2013 by James Ayre
The large asteroid 99942 Apophis will be passing close by the Earth on Wednesday night, not close enough for an impact to be a danger though. There is a slight chance of an impact occurring on Friday, April 13, 2036, though. The Earth, and the asteroid nicknamed Apophis, follow a very similar orbit around the Sun and will eventually impact.
With the close fly-by on Wednesday night researchers will have a good opportunity to learn more about the asteroid, getting a better idea of its future trajectory.
“The 27-megaton asteroid has a diameter of roughly three football fields, and would pack a society-ending punch if it really impacted Earth. So astronomers are interested in nailing down its trajectory and characteristics.”
It won’t be a particularly bright asteroid, with only an apparent magnitude of 19.7. It probably won’t be visible with ‘backyard’ type telescopes, but will be visible with larger telescopes in darker places, such as the Slooh space camera in the Canary Islands.
The asteroid “is named for the Egyptian god Apep the Uncreator, who tried to swallow the sun god Ra as he crossed the sky. The Greeks called him Apophis, and he personified death, destruction and chaos.”
When first discovered, the asteroid Apophis was estimated “to have a 2.7 percent chance of impacting Earth in 2029, but this was later dramatically reduced. It will still give Earth a close shave, flying by within the range of our geosynchronous satellites. And there’s a very small chance that during that approach, Earth’s gravitational influence will tug on it just enough to bring it back for good in 2036. Understanding its spin direction, size and other characteristics will help answer that question.”
“Or, new measurements could also confirm it will safely pass more than 30.5 million miles from Earth in 2036.”
For those interested, you can watch the asteroid pass by on the SLOOH space camera website.
While it’s currently thought to be unlikely that the asteroid Apophis will impact the Earth in the near future, there is of course some uncertainty. The factors that go into determining the exact orbit of asteroids aren’t completely understood, there are many changing circumstances that can influence the path that such objects eventually take. For now though, potential impacts are thought to be more likely to occur from completely unknown asteroids than any known ones.
Image Credits: ESA-P.Carrie; Figure by J. Giorgini (JPL)
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