Asteroid Has Outside Chance of Hitting Earth in 2029
By Robert Roy Britt
Senior Science Writer
posted: 24 December 2004
09:58 am ET
http://space.com/scienceastronomy/asteroid_risk_041224.html Scientists said Thursday that a recently discovered asteroid has a chance of hitting Earth in the year 2029, but that further observations would likely rule out the impact scenario.
The asteroid is named 2004 MN4. It was discovered in June and spotted again this month. It is about a quarter mile (400 meters) wide.
That's bigger than the space rock that carved meteor crater in Arizona, and bigger than one that exploded in the air above Siberia in 1908, flattening thousands of square miles of forest. If an asteroid the size of 2004 MN4 hit the Earth, it would do considerable localized damage.
Scientists stressed, however, that the rock would likely miss the planet.
A statement was released by NASA asteroid experts Don Yeomans, Steve Chesley and Paul Chodas.
"The odds of impact, presently around 1 in 300, are unusual enough to merit special monitoring by astronomers, but should not be of public concern," the scientists said. "These odds are likely to change on a day-to-day basis as new data are received. In all likelihood, the possibility of impact will eventually be eliminated as the asteroid continues to be tracked by astronomers around the world."
The scientists project an asteroid's future travels based on observations of its current orbit around the Sun. On computer models, the future orbits are not lines but rather windows of possibility. The orbit projections for 2004 MN4 on April 13, 2029 cover a wide swath of space that includes the location where Earth will be. Additional observations will allow refined orbit forecasts -- more like a line instead of a window.
The asteroid will be easily observable in coming months, so scientists expect to figure out its path. Already late Thursday, the risk assessment was shrinking slightly, according to the Asteroid/Comet Connection, a web site that monitors space rock hazards.
Most asteroids circle the Sun in a belt between Mars and Jupiter. But some get gravitationally booted toward the inner solar system.
The 323-day orbit of 2004 MN4 lies mostly within the orbit of Earth. The asteroid approaches the Sun almost as close as the orbit of Venus. It crosses near the Earth's orbit twice on each of its passages about the Sun.
2004 MN4 was discovered on June 19 by Roy Tucker, David Tholen and Fabrizio Bernardi of the NASA-funded University of Hawaii Asteroid Survey. It was rediscovered on Dec. 18 from Australia by Gordon Garradd of the Siding Spring Survey. More than three dozen observations have been made, with more expected to roll in from other observatories this week.
Earlier this week, scientists announced that a small space rock had zoomed past Earth closer than the orbits of some satellites.
Topic: 1/4 mile wide Asteroid may hit earth in 2029 (Read 2491 times)