It's called Apophis. It's 390m wide. And it could hit Earth in 31 years time
Scientists call for plans to change asteroid's path Developing technology could take decades
Alok Jha
Wednesday December 7, 2005
In Egyptian myth, Apophis was the ancient spirit of evil and destruction, a demon that was determined to plunge the world into eternal darkness.
A fitting name, astronomers reasoned, for a menace now hurtling towards Earth from outerspace. Scientists are monitoring the progress of a 390-metre wide asteroid discovered last year that is potentially on a collision course with the planet, and are imploring governments to decide on a strategy for dealing with it.
Nasa has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere.
And, scientists insist, there is actually very little time left to decide. At a recent meeting of experts in near-Earth objects (NEOs) in London, scientists said it could take decades to design, test and build the required technology to deflect the asteroid. Monica Grady, an expert in meteorites at the Open University, said: "It's a question of when, not if, a near Earth object collides with Earth. Many of the smaller objects break up when they reach the Earth's atmosphere and have no impact. However, a NEO larger than 1km [wide] will collide with Earth every few hundred thousand years and a NEO larger than 6km, which could cause mass extinction, will collide with Earth every hundred million years. We are overdue for a big one."
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In spring next year, there will be another opportunity for radar observations of Apophis that will help astronomers work out possible future orbits of the asteroid more accurately.
If, at that stage, they cannot rule out an impact with Earth in 2036, the next chance to make better observations will not be until 2013. Nasa has argued that a final decision on what to do about Apophis will have to be made at that stage.
"It may be a decision in 2013 whether or not to go ahead with a full-blown mitigation mission, but we need to start planning it before 2013," said Prof Fitzsimmons. In 2029, astronomers will know for sure if Apophis will pose a threat in 2036. If the worst-case scenarios turn out to be true and the Earth is not prepared, it will be too late. "If we wait until 2029, it would seem unlikely that you'd be able to do anything about 2036," said Mr Yates.
Alok Jha
Wednesday December 7, 2005
In Egyptian myth, Apophis was the ancient spirit of evil and destruction, a demon that was determined to plunge the world into eternal darkness.
A fitting name, astronomers reasoned, for a menace now hurtling towards Earth from outerspace. Scientists are monitoring the progress of a 390-metre wide asteroid discovered last year that is potentially on a collision course with the planet, and are imploring governments to decide on a strategy for dealing with it.
Nasa has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere.
And, scientists insist, there is actually very little time left to decide. At a recent meeting of experts in near-Earth objects (NEOs) in London, scientists said it could take decades to design, test and build the required technology to deflect the asteroid. Monica Grady, an expert in meteorites at the Open University, said: "It's a question of when, not if, a near Earth object collides with Earth. Many of the smaller objects break up when they reach the Earth's atmosphere and have no impact. However, a NEO larger than 1km [wide] will collide with Earth every few hundred thousand years and a NEO larger than 6km, which could cause mass extinction, will collide with Earth every hundred million years. We are overdue for a big one."
...
In spring next year, there will be another opportunity for radar observations of Apophis that will help astronomers work out possible future orbits of the asteroid more accurately.
If, at that stage, they cannot rule out an impact with Earth in 2036, the next chance to make better observations will not be until 2013. Nasa has argued that a final decision on what to do about Apophis will have to be made at that stage.
"It may be a decision in 2013 whether or not to go ahead with a full-blown mitigation mission, but we need to start planning it before 2013," said Prof Fitzsimmons. In 2029, astronomers will know for sure if Apophis will pose a threat in 2036. If the worst-case scenarios turn out to be true and the Earth is not prepared, it will be too late. "If we wait until 2029, it would seem unlikely that you'd be able to do anything about 2036," said Mr Yates.