January 29, 2012

Asteroid Close Calls: Past, Present and Future

The bus-sized asteroid that flew past Earth on Friday may have garnered headlines, but it is far from alone, as experts claim that approximately 50 million objects pass by our planet each day.

As previously reported here on redOrbit.com, Asteroid 2012 BX34, which was first detected on Wednesday, skimmed past Earth at a distance about one-fifth to one-sixth that of the Moon two days ago.

While astronomers reportedly said that there was no cause for alarm, and that the 20- to 62-foot asteroid would have not survived our atmosphere had it even gotten close enough, it nonetheless was one of the 20 closest asteroids every to pass by our planet.

Asteroid 2012 BX34 was one of 30 objects this year to pass within the distance from the Earth to the Moon, AFP's Kerry Sheridan reported on Saturday.

According to James Orr of the Telegraph, there have been several other close calls during the past two years. In February 2011, a small asteroid identified as 2011 CQ1 was spotted by American space agency astronauts at less than 5500km above the Earth's surface in the mid-Pacific region.

Last June, Orr reports that "a newly discovered asteroid the size of an office block narrowly missed Earth - coming 23 times closer than the moon“¦ The space rock, named 2011 MD, reached within 11,000 miles of our atmosphere and gave off a light bright enough to be seen through a small telescope."

Likewise, there were a pair of asteroids that narrowly missed Earth in September 2010, including one that passed within 50,000 miles of our world.

"In November last year, a much a larger asteroid called 2005 YU55 made its closest fly-by of Earth in 200 years," Sheridan said. "The near-spherical asteroid, 1,300 feet (400 meters) in diameter, passed by at a distance of 201,700 miles (324,600 kilometers), as measured from the center of Earth, NASA said."

In June 2010, NASA spotted a potential future risk -- an 1,800 foot wide asteroid that the Telegraph says has a one in 1,000 chance of colliding with Earth in 2182. That collision, Orr claims, could "create more damage than that of the atomic bombing of Hiroshima."

According to some experts, in order for an asteroid to cause any real damage to Earth, it needs to measure at least 450 feet. With such potential dangers in our planet's future, European scientists have begun development on an asteroid shield that would help protect mankind should a near-Earth object (NEO) this size ever breaches Earth´s atmosphere.

The project, which has been dubbed NEOShield, has received "significant" funding from the European Commission, according to Space.com Columnist Leonard David. It has reportedly already gained the support of universities, research institutes and businesses in Germany, France, Spain, the UK, Russian, and the US.

"The primary aim of NEOShield is to investigate in detail the three most promising asteroid threat-reduction techniques: kinetic impactors, gravity tractors, and the explosive blast-deflection method," David said, adding that the project "could take up to three years to complete, and the goal is to create a device that would repel asteroids by using projectiles or explosives."


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