Posted on 07/23/2002 7:00:00 PM PDT by Lorenb420
Not at all; there's just not much we can do about it now. The two things we need are deliverable propulsion mechanisms (I recommend nuclear rockets for the near term) and a lot of lead time. The longer the lead time, the less integrated thrust we need. The best method would be to identify all of the potential doomsday rocks and affix solar sails to them. Small amounts of thrust could be applied continuously to the rocks without the need to replenish the fuel supply. The sails could be tacked by commands from Earth so that the thrust is always in a useful direction. After enough time, all of the rocks so equipped could be steered into orbits that don't ever cross Earth's orbit. (It is also possible that some of them could be steered so that they enter into orbit about the Earth someday.)
As for the rock that will potentially hit us in 2019, I doubt we could deliver enough delta-v to it to change the probability of collision. We don't have an efficient method of exerting thrust upon it, we don't have a vehicle capable of hauling such a thrust mechanism to it, the lead time is short enough that the integrated thrust requirements are already substantial, and those requirements are increasing as the inverse of the remaining lead time.
Then again, necessity is the mother of invention.
"The error in our knowledge of where NT7 will be on 1 February 2019 is large, several tens of millions of kms," he said.Given that the earth's radius is only 4000 miles (less than 6000km), the ratio of its cross section to the area within which the data suggest the nearest-approach to occur is less than 36 million divided by the square of 20 million. I reckon the odds against a collision are at least 10 million to one.
sounds about right--as Newspaper headlines go . . .
But as a practical matter nothing can be done until such time, if any, as we know the direction from the earth's center to the closest approach. And nothing should be done until the uncertainty is reduced to less than one million klicks. If there's still a possible problem it would be time to start working on a launch against it. You'd want to launch two, for some redundancy.
You wouldn't want to launch at all if that direction was so easily determined that you knew the collision hazzard was zero, but you'd want them to arrive as soon as you knew the direction of the closest approach. And if you were truly sure of that direction, and that you were pushing to increase the miss distance, you'd about as well to use the nukes once they arrived on target. You aren't gonna deflect it by very much, so you have to push ASAP and you have to push in the right direction.
It could be true that you can't possibly prevent the collision, because by the time you can know which way to push the asteroid is too close. But that depends on the mass of the asteroid and on how centered on the earth the asteroid is targeted. I guess you time your launch, if any, on your best guess as to how soon you have to know the direction to be able to do any good. And you decide which way to deflect only as you have the opportunity to attempt to do so.
It's all a question of how well you've measured the trajectory and how much computing power you can throw at the problem. If you've tracked it long enough, you can predict where it's going to go to within a gnat's eyebrow.
. . . and if you've tracked it long enough, it has already either hit or, more likely by far, missed by hundreds of miles. The bigger object you find, the less effect you can have on its trajectory with a given bopper--and the sooner you'd better bop it, so the effect accumulates over time.The conclusion is that you do well to detect early, and to refine your estimate of trajectory rapidly when you do detect. Does Hubble's different perspective help, and would a deep space probe be enough better to justify its cost?
I have a career path for my 12 year old.
Asteroid Exploder
LOL!!!
What's the frequemcy, Kenneth?
They don't use Hubble for tracking asteroids, and I'm not sure it could do a far better job than a smaller, ground-based telescope. The first order of business is to find the darn things, and for that you need more eyes rather than better eyes.
I'm just guessing here, but I expect that the biggest advantage to a space-based telescope would be to give you a long baseline for parallax measurements. If that's right, the goal would be to get the space-based telescope as far away from Earth as possible. Perhaps a Moon-based telescope would be a good solution.
. . . which would seem to argue for getting a telescope into deep space to get some serious parallax. Possibly a Pluto-type solar orbit?
No, that would not be useful. Most Earth-crossing asteroids are going to have orbits that are comparable to Earth's orbit, so the baseline you really need is much smaller than that. Further, you'd need one amazing telescope--a super-Hubble--to spot something so faint from that far out, and you sure can't service it out there. And finally, it would take many years to get such a device into such an orbit, assuming you had the capability to launch such an monster out there.
Wait a tick...they have only ONE data point and they have already decided we're in the clear???
I stand corrected...pardon.
Dr Yeomans added: "While we cannot completely rule out an impact possibility for 1 February 2060, it seems very likely that this possibility will soon be ruled out as well."I'll be 110 on 1 Feb, 2060. If it doesn't get me then, it probably won't get me.
Which of course it will, given Murphy's Law. These astronomers are a bit too glib with their prognostications (apologies to RadioAstronomer - who would NEVER make such an assertion without sufficient data).
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