Posted on 05/22/2006 4:52:42 PM PDT by blam
Risk of asteroid smashing into Earth reduced
12:50 22 May 2006
NewScientist.com news service
Kelly Young
The asteroid's path through the solar system will bring it to close to Earth in 2029 (Image: JPL/NASA)
The danger to Earth from an asteroid called Apophis, which once looked relatively likely to hit the Earth, appears to be waning.
The odds of an Earth impact by Apophis in 2036 have now been reduced from 1 in 5500 to 1 in 24,000, following new radar measurements taken by the Arecibo Observatory in Puerto Rico.
On 6 May 2006, with the asteroid 42 million kilometres away, astronomers with NASA's Jet Propulsion Laboratory measured the speed of the asteroid with radar. They found its speed was 6 millimetres per second different than what they had expected.
"It's just a small correction in the orbit that propagates forward in time enough to reduce the probability of impact," says Jon Giorgini, senior analyst with the Solar System Dynamics Group at JPL in Pasadena, California, US.
Before this observation, it was thought that in 2029 Apophis would approach our planet to within about 5.86 Earth radii. With these new measurements, the estimated distance has been pushed back to 5.93 Earth radii.
Through the keyhole This seemingly small difference is crucial since if the asteroid's path carries it through a certain "keyhole" – in this case, a specific region of space near Earth just 600 metres across – Apophis's orbit could be perturbed enough to put it on a collision course with Earth in 2036.
The asteroid, which is about 320 metres in diameter, ranks a 1 on the Torino scale. Zero means an object has no chance of hitting Earth and a 10 means certain impact. At one point, Apophis rated a 4.
Because the asteroid will travel too close to the Sun for radar measurements, this will probably be the last chance to get good radar data of Apophis for several years. But in 2013, the asteroid should be in a position where astronomers can track it with radar again.
"I think we'll be able to put this to rest one way or the other," Giorgini told New Scientist.
Giggle factor However, astronomers may be able to get optical data on Apophis before then, says Dave Tholen, an astronomer with the University of Hawaii, US.
In January, Tholen and his team plan to observe Apophis to determine its rotation rate. This is important because if the asteroid is heated unevenly by sunlight, the radiation can impart a small force on the asteroid. That force may be miniscule, but when it accumulates over 20 years, it can make the difference in whether Apophis passes through the keyhole or not, he says.
Even though the odds of this particular asteroid hitting Earth have been reduced dramatically, its early threat alerted the public to the potential of asteroid impacts. "Compared to 10 years ago, I'd say the giggle factor has been reduced considerably," Tholen says.
I think the moon is what we really need to worry about. The moon is like a giant cue ball and someday an asteroid is going to strike it and send it right into the planet earth and sink us into the corner pocket of space. We can only hope that the asteroid puts too much English on the moon cue ball, causing it to veer into Mercury or Venus instead, or maybe even scratch entirely.
The big, huge meteor headed toward Earth. Could nothing stop it? Maybe Bob could. He was suddenly on top of the meteor - through some kind of a space warp or something. "Go, Bob, go!" yelled one of the generals. "Give me that" said the big-guy general as he took the microphone away. "Listen, Bob," he said. "you've got to steer that meteor away from Earth." "Yes, but how?" thought Bob. Then he got an idea. Right next to him there was a steering wheel sticking out of the meteor. --Jack Handey
Unfortunately it is also in the region of physics between classical mechanics and statistical thermodynamics: too many bodies and variables for one and not enough for the other.
Are you kidding? It only takes them one second to scream, "BUSH'S FAULT!," no matter what the problem.
Sounds like a Vogon Destructor Fleet to me....
There was a sci-fi book a few years ago that had a painting of the moon on the cover--just after it got hit by a large asteroid kind of object that came from outside the solar system moving so fast that they could do nothing but watch. Earth would get hit by the spray.
Yeah, but I won't hear them over my screaming.
The fact that we won't really know until 2013 tells us the margin of error is sufficiently large that they can't rule out a collision. Not comforting but the probabilities look good!
Is there any possible way we could alter it`s course so it crashes dead on right on top of the New York times building?
LOL
The apotheosis of Apophis?
http://touregypt.net/godsofegypt/apep.htm
http://touregypt.net/featurestories/apep.htm
We all hate the Times, but let's not take out New York City because of it, o'kay?
Shumaker?
Levy?
Clube?
Napier?
Ha!... If we lose the Moon, we're in deep trouble: There go the seasons, there go the tides, there goes our familiar 24-hour day.
...why would that bother the length of the day or the seasons? :P
Thanks Blam. I think we've got one, but lemme look...
Nope, I guess not. I think I just posted the 'fo in that old Apophis topic (From before it got the name).
Shumaker or Levy. I think technically they are amateur astronomers.
I'm no astronomer, but I did stay at the Holiday Inn Express one night, where I saw this particular explanation on the Science Channel!
Well, mebbe. But I'm still gonna carry my umbrella that day.
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