Chinese scientists come up with plan to save Earth from asteroid hit

A group of Chinese scientists have proposed using a solar sail to prevent the possible collision of Apophis, a 46 million ton asteroid, with the Earth in 2036.

The asteroid, which is 270 meters in diameter, will approach Earth at a distance of 37,000-38,000 kilometers in 2029. In 2036 Apophis may come back and collide with Earth on April 13, 2036.

According to scientists, the chance of a collision in 2036 is extremely slim and the asteroid would likely disintegrate into smaller parts and smaller collisions with Earth could occur in the following years.

However, a group of Chinese astronomers headed by Shengping Gong of Tsinghua University in Beijing published an article proposing to place a small spacecraft with a solar sail into a retrograde orbit in order to change the asteroid's trajectory.

The project may be difficult to realize as all kinds of variations in the solar wind could send the spacecraft wildly off course, according to Technologyreview.com.The asteroid, discovered in 2004, is considered the largest threat to our planet, although NASA scientists say the likelihood of a hazardous strike on Earth in 2036 is unlikely. 

The retrograde orbit will give the spacecraft an impact velocity of 90km/s which, if this is done well enough in advance, will prevent Apophis from returning to Earth. 

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SOURCE : http://www.spacedaily.com/reports/Chinese_scientists_come_up_with_plan_to_save_Earth_from_asteroid_hit_999.html