It has been mentioned elsewhere on the forum, the fact that we are due for an Asteroid strike. Assuming that we do, at sometime in the near future, do our World leaders have any contihgency plans to put into place to deal with such a threat.
I am presuming that if we have the solution, it is viable, however, IF the Asteroid is so large than it can’t be destroyed prior to it hitting Earth, what would you do, considering that it would be , say in 6 months time?.
Lincoln. 7
By: PMN - 25th February 2011 at 15:09
as opposed to the years it would take according to PNM.
Where did I say something would take years? :confused:
By: PMN - 25th February 2011 at 15:08
Hmm, that’s somewhat beyond me and I’m fairly sure it’s beyond probably 99.99% of people on this forum. That being the case I can’t really form a judgement on whether the numbers work or not but I still can’t really see how it can practically work. If I see it happen and work then I’ll believe it, until then I’m skeptical.
By: Lincoln 7 - 25th February 2011 at 15:06
You’re being serious, aren’t you? 😮
Fear not. Help is at hand.
Nah!! PNM cleared it up nicely. :rolleyes:
Lincoln .7
It still however seems unreal that a flimsy solar sail could deflect a huge mass in 6 months as I did state, as opposed to the years it would take according to PNM.
Lincoln .7
By: Grey Area - 25th February 2011 at 15:04
So how do we get a sail alongside a meteor travelling at speeds between 10,000 and 40,000 metres per second for long enough to exert any kind of force for long enough to have any effect? I’m not really seeing how this idea is practically possible, and I still don’t really believe that a force of probably 1 or 2 newtons is really enough to even vaguely influence the trajectory of a meteor.
I’m no rocket scientist, but these chaps seem to have worked the numbers out.
I prefer the “white paint” option myself. :p
By: Lincoln 7 - 25th February 2011 at 15:00
It’s a good job that the Universe disagrees with you then, otherwise rocket motors wouldn’t work in space.
But even the tiniest deflection applied over enough time, preferably over years, may well be enough to avoid impact.
Hence why early detection is so vital.
Ah well, no point in worrying about it. The one with our planet’s name written on it will probably come in from sunward and we’ll literally never know what hit us.
Sort of “Be aware of the Hun from the sun” idea.
Lincoln .7
By: Grey Area - 25th February 2011 at 14:58
As I understand it,:p every action has an equal and opposite reaction, as space is a vaccume, exactly what resistance do the rockets have to push against to give tthem their forwards thrust?
You’re being serious, aren’t you? 😮
Fear not. Help is at hand.
By: PMN - 25th February 2011 at 14:57
So how do we get a sail alongside a meteor travelling at speeds between 10,000 and 40,000 metres per second for long enough to exert any kind of force for long enough to have any effect? I’m not really seeing how this idea is practically possible, and I still don’t really believe that a force of probably 1 or 2 newtons is really enough to even vaguely influence the trajectory of a meteor. Alright, I’m fat and heavy but that wouldn’t even move me never mind several hundred tons of rock and metal.
Lincoln 7,
“A reaction engine is an engine or motor which provides propulsion by expelling reaction mass, in accordance with Newton’s third law of motion. This law of motion is most commonly paraphrased as: “For every action force there is an equal, but opposite, reaction force”.
Examples include both jet engines and rocket engines, and more uncommon variations such as Hall effect thrusters, ion drives, mass drivers and nuclear pulse propulsion.”
Lance is bang right on this one! Rocket thrusters use exactly the same principle of movement as a turbofan engine on earth and squids/octopuses in the sea, only obviously the absence of oxygen in the atmosphere (or indeed, the absence of any atmosphere at all) means they have to carry their own and mix them to make combustion possible.
By: Lincoln 7 - 25th February 2011 at 14:56
It’s a good job that the Universe disagrees with you, otherwise rocket motors wouldn’t work in space.
As I understand it,:p every action has an equal and opposite reaction, as space is a vaccume, exactly what resistance do the rockets have to push against to give them their forwards thrust?.
Unlike you G.A. I don’t work for NASA 😉
Lincoln .7
By: Grey Area - 25th February 2011 at 14:55
Who said it was easy?
By: Sky High - 25th February 2011 at 14:50
So we have to launch this sail, align its trajectory to that of the asteroid, accelerate it to a few thousand metres per second to bring it alongside, but at an angle, deflecting it away from the earth’s orbit. Easy, peasy – job done.;)
By: Grey Area - 25th February 2011 at 14:49
Unless Newton actualy went up into Space, you are assuming that Newtons 3rd would work in space.I however would disagree with you 😉
It’s a good job that the Universe disagrees with you then, otherwise rocket motors wouldn’t work in space.
There is resistance though. Inertia doesn’t cease to exist in a vacuum and would still present a great resistance, at those speeds, to a change in direction.
But even the tiniest deflection applied over enough time, preferably over years, may well be enough to avoid impact.
Hence why early detection is so vital.
Ah well, no point in worrying about it. The one with our planet’s name written on it will probably come in from sunward and we’ll literally never know what hit us.
By: PMN - 25th February 2011 at 14:49
There is resistance though. Inertia doesn’t cease to exist in a vacuum and would still present a great resistance, at those speeds, to a change in direction. If this is a very real idea with genuine scientific validity (that has another reference somewhere on the internet) then I’ll happily admit to having learned something new, but if it’s purely a theoretical idea then I have to admit I’m extremely skeptical of it!
By: Lincoln 7 - 25th February 2011 at 14:48
It may be travelling very quickly, but it’s doing so in a vacuum.
Newton’s Third, mate….. 😀
I am aware of Newtons laws, I will have you know old chap, that I went to an approved school!! 😀
Unless Newton actualy went up into Space, you are assuming that Newtons 3rd would work in space.I however would disagree with you 😉
Also his 2nd would not be relevant either.
Lincoln. 7
By: Grey Area - 25th February 2011 at 14:44
That doesn’t affect its mass. Bearing in mind that at a distance of 1AU the sun exerts a force of only 9 newtons per square mile with its light output, surely it would take one hell of a solar sail to deflect something with the size and energy of a meteor?
No, it doesn’t affect the mass. Or the inertia.
But it does mean that there is no atmospheric resistance to the small sideforce applied by the sail.
A very small sideforce exerted over a period of time would produce a very small deflection.
But that would be all that was needed.
By: PMN - 25th February 2011 at 14:29
but it’s doing so in a vacuum.
That doesn’t change the fact it has a tremendous amount of energy and to influence that you also need tremendous energy. Bearing in mind that at a distance of 1AU the sun exerts a force of only 9 newtons per square mile with its light output, surely it would take one hell of a solar sail to deflect something with the size and energy of a meteor?
By: PeeDee - 25th February 2011 at 14:26
Not quite true. Granted they don’t last long but I’ve seen them at dawn when it’s been very light indeed. You certainly don’t need to be out in the sticks to see them.
Yes indeed, I didn’t mean all SStars. The ones that leave any trail of size are apple sized. I spose a diamond the size of sand could leave a trail……speaking of which, the ones that fall to ground are a good source of perfect Diamonds. There are teams which search the Salt flats for such. The items they find are Grape sized or Plum. They must have been as big as a house upon entry!
I’m outside with the Camera at every Meteor shower. Unfortunately, with the camera, I haven’t seen the massive showers which were visible in the 80’s when I saw the Leonids burst of about 2,000 an hour between 2 and 3am.
Apparently, were are in a different part of our general orbit and the massive showers won’t be back for a couple more decades yet I think.
By: PeeDee - 25th February 2011 at 14:19
When you Hoover, do you use a Dyson to do the vacuum?
By: PMN - 25th February 2011 at 14:18
As already stated, grains of Sand sized….but that’s the smallest. They don’t produce a Shooting Star, maybe a tiny flick of light, but you’d need to live way in the sticks for the sky to be dark enough.
Not quite true. Granted they don’t last long but I’ve seen them at dawn when it’s been very light indeed. You certainly don’t need to be out in the sticks to see them.
By: Grey Area - 25th February 2011 at 14:17
G.A. Having watched TV re your suggestion regarding a Solar Sail, can you explain just how that flimsy item could deflect an Asteroid travelling at a very high speed, not being sarcastic, but just how do you think that would be of use?
It may be travelling very quickly, but it’s doing so in a vacuum.
Newton’s Third, mate….. 😀
By: PeeDee - 25th February 2011 at 14:08
As already stated, grains of Sand sized….but that’s the smallest. They don’t produce a Shooting Star, maybe a tiny flick of light, but you’d need to live way in the sticks for the sky to be dark enough.
The S. Stars we see, that take up, say a 1/4 of the arc of sky…are about the size of an Apple up to the size of a House. They burn different colours if you are lucky, and speed of Burn obviously depends on the constituant materials.
I have been fortunate enough to see a “Fireball”.
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February 25, 2011 at 12:21 pm