benny
09-12-2005, 12:23 AM
Feck peeps, this is scary....
It's called Apophis. It's 390m wide. And it could hit Earth in 31 years timeScientists call for plans to change asteroid's path Developing technology could take decades
Alok Jha
Wednesday December 7, 2005
Guardian
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."
Apophis had been intermittently tracked since its discovery in June last year but, in
December, it started causing serious concern. Projecting the orbit of the asteroid into
the future, astronomers had calculated that the odds of it hitting the Earth in 2029 were
alarming. As more observations came in, the odds got higher.
Having more than 20 years warning of potential impact might seem plenty of time. But,
at last week's meeting, Andrea Carusi, president of the Spaceguard Foundation, said
that the time for governments to make decisions on what to do was now, to give
scientists time to prepare mitigation missions. At the peak of concern, Apophis
asteroid was placed at four out of 10 on the Torino scale - a measure of the threat
posed by an NEO where 10 is a certain collision which could cause a global
catastrophe. This was the highest of any asteroid in recorded history and it had a 1 in
37 chance of hitting the Earth. The threat of a collision in 2029 was eventually ruled out
at the end of last year.
Alan Fitzsimmons, an astronomer from Queen's University Belfast, said: "When it
does pass close to us on April 13 2029, the Earth will deflect it and change its orbit.
There's a small possibility that if it passes through a particular point in space, the
so-called keyhole, ... the Earth's gravity will change things so that when it comes back
around again in 2036, it will collide with us." The chance of Apophis passing through
the keyhole, a 600-metre patch of space, is 1 in 5,500 based on current information.
There are no shortage of ideas on how to deflect asteroids. The Advanced Concepts
Team at the European Space Agency have led the effort in designing a range of
satellites and rockets to nudge asteroids on a collision course for Earth into a different
orbit.
No technology has been left unconsidered, even potentially dangerous ideas such as
nuclear powered spacecraft. "The advantage of nuclear propulsion is a lot of power,"
said Prof Fitzsimmons. "The negative thing is that ... we haven't done it yet. Whereas
with solar electric propulsion, there are several spacecraft now that do use this
technology so we're fairly confident it would work."
The favoured method is also potentially the easiest - throwing a spacecraft at an
asteroid to change its direction. Esa plans to test this idea with its Don Quixote
mission, where two satellites will be sent to an asteroid. One of them, Hidalgo, will
collide with the asteroid at high speed while the other, Sancho, will measure the
change in the object's orbit. Decisions on the actual design of these probes will be
made in the coming months, with launch expected some time in the next decade. One
idea that seems to have no support from astronomers is the use of explosives.
Prof Fitzsimmons. "If you explode too close to impact, perhaps you'll get hit by several
fragments rather than one, so you spread out the area of damage."
In September, scientists at Strathclyde and Glasgow universities began computer
simulations to work out the feasibility of changing the directions of asteroids on a
collision course for Earth. 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.
It's called Apophis. It's 390m wide. And it could hit Earth in 31 years timeScientists call for plans to change asteroid's path Developing technology could take decades
Alok Jha
Wednesday December 7, 2005
Guardian
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."
Apophis had been intermittently tracked since its discovery in June last year but, in
December, it started causing serious concern. Projecting the orbit of the asteroid into
the future, astronomers had calculated that the odds of it hitting the Earth in 2029 were
alarming. As more observations came in, the odds got higher.
Having more than 20 years warning of potential impact might seem plenty of time. But,
at last week's meeting, Andrea Carusi, president of the Spaceguard Foundation, said
that the time for governments to make decisions on what to do was now, to give
scientists time to prepare mitigation missions. At the peak of concern, Apophis
asteroid was placed at four out of 10 on the Torino scale - a measure of the threat
posed by an NEO where 10 is a certain collision which could cause a global
catastrophe. This was the highest of any asteroid in recorded history and it had a 1 in
37 chance of hitting the Earth. The threat of a collision in 2029 was eventually ruled out
at the end of last year.
Alan Fitzsimmons, an astronomer from Queen's University Belfast, said: "When it
does pass close to us on April 13 2029, the Earth will deflect it and change its orbit.
There's a small possibility that if it passes through a particular point in space, the
so-called keyhole, ... the Earth's gravity will change things so that when it comes back
around again in 2036, it will collide with us." The chance of Apophis passing through
the keyhole, a 600-metre patch of space, is 1 in 5,500 based on current information.
There are no shortage of ideas on how to deflect asteroids. The Advanced Concepts
Team at the European Space Agency have led the effort in designing a range of
satellites and rockets to nudge asteroids on a collision course for Earth into a different
orbit.
No technology has been left unconsidered, even potentially dangerous ideas such as
nuclear powered spacecraft. "The advantage of nuclear propulsion is a lot of power,"
said Prof Fitzsimmons. "The negative thing is that ... we haven't done it yet. Whereas
with solar electric propulsion, there are several spacecraft now that do use this
technology so we're fairly confident it would work."
The favoured method is also potentially the easiest - throwing a spacecraft at an
asteroid to change its direction. Esa plans to test this idea with its Don Quixote
mission, where two satellites will be sent to an asteroid. One of them, Hidalgo, will
collide with the asteroid at high speed while the other, Sancho, will measure the
change in the object's orbit. Decisions on the actual design of these probes will be
made in the coming months, with launch expected some time in the next decade. One
idea that seems to have no support from astronomers is the use of explosives.
Prof Fitzsimmons. "If you explode too close to impact, perhaps you'll get hit by several
fragments rather than one, so you spread out the area of damage."
In September, scientists at Strathclyde and Glasgow universities began computer
simulations to work out the feasibility of changing the directions of asteroids on a
collision course for Earth. 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.