A recently discovered asteroid may approach Earth closely in 2040, but it’s extremely unlikely that it will crash and wreak havoc.
Asteroid 2011 AG5 was discovered on January 8, 2011 by the Mt. Lemmon Survey using at the University of Arizona’s Steward Observatory in the Catalina Mountains north of Tucson. Mt. Lemmon is one of three surveys that participate in the Catalina Sky Survey, charged by Congress to inventory 90 percent or better of all near-Earth objects (NEOs) 459 feet wide (140 meters) or larger. These are the ones that could cause potential destruction should one come crashing down.
At around 460 feet across, 2011 AG5 just makes the cut as a potentially hazardous object. As of February 21, 2012, 8751 Near-Earth asteroids have been discovered. Some 839 of these NEOs have a diameter of approximately 0.6 miles (1 km) or larger. 1290 of the NEOs have been classified as Potentially Hazardous Asteroids. These are the ones whose orbits intersect Earth’s at distances of 4.65 million miles or less and measure 360 feet (110 meters) or larger across.
It takes many observations to derive a highly accurate orbit for a newly-discovered asteroid or comet. Since nobody can see 2011 AG5 right now because it’s in the daytime sky, we’ll have to wait until it’s better placed in September 2013.
Then astronomers can make more observations to refine the object’s orbit, so we’ll have a better idea of its future travels.
Don Yeomans, manager of NASA’s Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif., says that it’s extremely rare for a near-Earth asteroid to impact Earth. 2011 AG5’s next near pass happens in February 2023 (1.2 million miles) and again in 2028 at 12.8 million miles. Earth’s gravitational attraction on the asteroid during these upcoming passes could potentially send it on a collision course with our planet on February 5, 2040, but the odds are quite small this will happen: only a 1-in-625 chance. That works out to piddling 0.16 percent. Yeomans fully expects the odds to drop even more once the orbit is refined.
On the Torino Impact Hazard Scale, 2011 AG5 rates only a “1”, defined as:
“A routine discovery in which a pass near the Earth is predicted that poses no unusual level of danger. Current calculations show the chance of collision is extremely unlikely with no cause for public attention or public concern. New telescopic observations very likely will lead to re-assignment to Level 0.”
With that, I’d say there’s no reason to sell your house or blow all your money. Sounds like we’ll all be around for a while longer.
(Credits for asteroid/comet montage: Montage by Emily Lakdawalla. Ida, Dactyl, Braille, Annefrank, Gaspra, Borrelly: NASA / JPL / Ted Stryk. Steins: ESA / OSIRIS team. Eros: NASA / JHUAPL. Itokawa: ISAS / JAXA / Emily Lakdawalla. Mathilde: NASA / JHUAPL / Ted Stryk. Lutetia: ESA / OSIRIS team / Emily Lakdawalla. Halley:: Russian Academy of Sciences / Ted Stryk. Tempel 1: NASA / JPL / UMD. Wild 2: NASA / JPL)