Posted on 04/18/2005 7:21:31 AM PDT by aculeus
A HUGE asteroid which is on a course to miss the Earth by a whisker in 2029 could go round its orbit again and score a direct hit a few years later.
Astronomers have calculated that the 1,000ft-wide asteroid called 2004 MN4 will pass by the Earth at a distance of between 15,000 and 25,000 miles — about a tenth of the distance between the Earth and the Moon and close enough to be seen with the naked eye.
Although they are sure that it will miss us, they are worried about the disturbance that such a close pass will give to the asteroid’s orbit. It might put 2004 MN4 on course for a collision in 2034 or a year or two later: the unpredictability of its behaviour means that the danger might not become apparent until it is too late.
As a safety precaution, some experts are calling for 2004 MN4 to be “tagged” with a transponder that would constantly radio its position. Scientists hope that this would provide enough warning to allow emergency action if necessary, possibly by diverting the object away from the Earth.Other instruments on the probe could provide information about its composition.
Benny Peiser, from Liverpool John Moores University, who is an expert on asteroid hazards, said: “We don’t know what that asteroid is made of and that might influence the way it’s affected by the Earth’s gravitational pull. There are other close approaches, in 2034 and 2035. In all likelihood it will produce an orbit that will not intercept the Earth, but we don’t know.”
The asteroid is big enough to cause damage on a regional scale, with an expected impact equivalent to a 1,000-megatonne explosion. It was discovered last June and its orbit plotted in detail by December. Startled astronomers calculated at one point that its chances of a direct hit on Friday, April 13, 2029, were 1 in 38. But additional calculations have set those fears to rest. The asteroid is now expected to miss but come close enough to be below the altitude of TV satellites. It should be visible as a rapidly moving point of light.
Brian Marsden, of the Harvard-Smithsonian Centre for Astrophysics in Cambridge, Massachusetts, expects the close encounter to increase the frequency of the asteroid’s orbit, creating the possibility of further close encounters every five to nine years.
An interceptor mission is feasible and Dr Peiser said that an opportunity would arise in 2012, when 2004 MN4 will be ten million miles from Earth. “That’s not a big distance as far as space missions go,” he said.
“This is most likely not the object with our number on it, but one day we will have to address this question and we’ll need the technology. A transponder mission should not be too complicated or costly, and would provide a lot of vital data.”
Copyright 2005 Times Newspapers Ltd.
That seals it, no need to change social security, the earth will be destroyed anyway!
April 13, 2029?
Damn, that'll be my 42nd birthday!
Gravity is obviously too dangerous. It should be banned.
We must elect Hillary Clinton as President.... she will save us.
The headline reminds me of SUV headlines. Maybe we can lure the asteroid away from us bu providing an incentive. If we only knew what asteroids liked best. Female asteroid?
>How does the asteroid lose enough kinetic energy to be captured by Earth's gravitational field?
The asteroid is currently in *solar* orbit. A near encounter with Earth would slightly deflect the asteroids orbit, by gravitationally tugging it to one side. It would still be in a solar orbit, just a slightly different one. However, the change in orbit cannot be accurately calculated until we know *exactly* how close it will pass by the Earth/Moon system (the moon will *also* tug slightly on the asteroid).
And with timescales of 30+ years, you also really need to factor in Jupiters gravitational effect as well.
Orbital mechanics is based on some pretty simple equations... when you only have two bodies. But in this circumstance, there are at least 5 that need to be accounted for. Extremely complex, requiring lots of computer power and *very* precise observations.
Yeah, OK, but it will be a "lossless" encounter, won't it? Maybe not.
Are they concerned that it will exchange momentum with the earth in a way that slows it down (as opposed to speeding it up as happens when we use Jupiter's gravitational field to shoot satellites out to Neptune, etc.)?
(steely)
Thats what the dinosaurs said.
Aha! They just want an excuse to use tax dollars to "tag it for safety", oh, and by the way, study the composition.
Why hasn't Jupiter gobbled this one up yet?
Billions of years, HAH!
Agreed. A many-body problem has no analytic solution - it requires zillions of calcs to find a best solution.
But by 2029, your wristwatch will be able to do those calcs.
This asteroid would be a local disaster if it hit, not a global one; the articles on it generally note this but it's interesting that people really don't seem to notice.
It's only 1000 ft across? Ummmm, maybe I'm missing something here but if it's coming so close, why are they going to tag it with a radio transmitter and not just blow the thing apart, thereby nullifying any risk at all?
> But by 2029, your wristwatch will be able to do those calcs.
Wristwatch? No, those will no longer exist. The brain-chip will simply display a heads-up display directly onto your retina (giving you the time in all time zones, along with your exact location), do your taxes, calculate orbital trajectories two millenia out, and project the fourteen most-likely-successful pick-up lines to the four-breasted genetically modified hottie in the corner.
Of course, if there's a "President Hillary" between now and then, that chip will *broadcast* your position, will modify your behavior, make you feel happy whenever Madame President appears (which will be every ten minutes) and will be mandatory.
We're not doomed. We need to catch it. Who ever catches it will be rich I tell you. RICH!
> Why hasn't Jupiter gobbled this one up yet?
Because the asteroids orbit goes nowhere near Jupiter.
Well it could change earth orbit and put us closer to the sun and cause globel warming.
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