01 Feb 09
1 edit
Originally posted by twhitehead…Of course it might be better to construct the first space elevator on the moon
Diamonds only burn at very high temperatures and I would expect nanotubes to have a similar high temperature burning point.
The issue of avoiding tracked objects could be solved simply by having a small jet engine on the counter wight so that it could sway from side to side. It would only need to move it a meter or two. I would expect it to be swaying qu current problem with the moon is that we must take with us any fuel required to lift of again.
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I am afraid that wouldn’t work because the moon spins on its axis at a much slower rate that that of the Earth (about once every 29 days if I remember correctly) which would mean the total length of the cable would have to be rather long despite the low gravity of the moon and I vaguely remember making a calculation that showed that the cable would have to be so long that the counterweight would interact with Earths gravity too much making it too unstable.
Also, putting a space elevator on the moon would defeat the main point of having a space elevator! -which is to make it easier to launch both people and satellites etc into space from EARTH without having to use expensive and energy inefficient ways of achieving escape velocity -what is the point of putting a space elevator on the moon if, in order to use it, you have to first transport whatever you want to go in space from the Earth to the moon first using inefficient means and only THEN put it into space using the space elevator!? -if it wasn’t for the fact that a space elevator on the moon would be too unstable anyway, the only way it could be useful to put it there is if satellites and other space machinery was manufactured on the moon itself (perhaps using robots) and then put into space by the elevator on the moon.
01 Feb 09
Originally posted by Andrew HamiltonI thought of a totally 1/4 baked idea: Suppose you have high towers on the north and south poles of the earth and the moon, then run cables between the two, you might get a highway to the moon that way, since the poles are fairly will lined up, I think within a few degrees. How's that for outside the box? Since the moon is pulling away from the earth, unreeling it as you go along might even generate energy.
[b]…Of course it might be better to construct the first space elevator on the moon
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I am afraid that wouldn’t work because the moon spins on its axis at a much slower rate that that of the Earth (about once every 29 days if I remember correctly) which would mean the total length of the cable would have to be rather long despite the low gra ...[text shortened]... d on the moon itself (perhaps using robots) and then put into space by the elevator on the moon.[/b]
01 Feb 09
3 edits
Originally posted by sonhouse…How's that for outside the box?.…
I thought of a totally 1/4 baked idea: Suppose you have high towers on the north and south poles of the earth and the moon, then run cables between the two, you might get a highway to the moon that way, since the poles are fairly will lined up, I think within a few degrees. How's that for outside the box? Since the moon is pulling away from the earth, unreeling it as you go along might even generate energy.
I think it is an excellent example of that 🙂
The idea at the very least “makes sense”. And, in effect, you would be using the whole of the moon as a counterweight.
I do just see two problems:
firstly, because the distance between the poles of the moon are not as great as the distance between the poles of the Earth, there wouldn’t quite be a direct straight line of sight from the centre of the lunar pole to the corresponding centre of the pole of the Earth so that you would need a rather tall tower on the Earths pole to make that work! (perhaps too tall to make it practical?)
secondly, the moon doesn’t orbit in an exact circle but has a slightly elliptical orbit -so the cable would have to keep changing its length -I think that could make it rather difficult although not impossible.
02 Feb 09
I don't think it is possible to utilize the electric potential from the ionosphere that way. The electricity would travel the path all at once and destroy it. If it were possible it would have been done by tapping into the electric potential from thunder storms a long time ago.
If it were possible it would provide the world energy and eliminate the need to burn fossil fuels forever. It would change the world for sure. Sounds too good to be true to me.
02 Feb 09
Originally posted by Metal BrainThe reason the energy from thunderstorms has not been tapped is because it is far to inconsistent to be useful - unless you know a place that has 24 hour / day thunderstorms.
I don't think it is possible to utilize the electric potential from the ionosphere that way. The electricity would travel the path all at once and destroy it. If it were possible it would have been done by tapping into the electric potential from thunder storms a long time ago.
If it were possible it would provide the world energy and eliminate the ne ...[text shortened]... urn fossil fuels forever. It would change the world for sure. Sounds too good to be true to me.
02 Feb 09
Originally posted by sonhouseThe polar axis is tilted 23 degrees in respect to ecliptic. The orbit of the Moon around the Earth is tilted additional degrees. This means that the moon is not visible from the pole during half its orbit.
I thought of a totally 1/4 baked idea: Suppose you have high towers on the north and south poles of the earth and the moon, then run cables between the two, you might get a highway to the moon that way, since the poles are fairly will lined up, I think within a few degrees. How's that for outside the box? Since the moon is pulling away from the earth, unreeling it as you go along might even generate energy.
Mathematical excercize: How high must a tower be, at the exact south pole, so you can see the moon from its top all the time?
02 Feb 09
Originally posted by FabianFnasIt would probably be easier to build a track around whichever line of latitude can see the moon all year round than to build a tall tower strong enough to hold the cable.
The polar axis is tilted 23 degrees in respect to ecliptic. The orbit of the Moon around the Earth is tilted additional degrees. This means that the moon is not visible from the pole during half its orbit.
Mathematical excercize: How high must a tower be, at the exact south pole, so you can see the moon from its top all the time?
02 Feb 09
Originally posted by twhiteheadI think that track would be something like 60 degrees north, or 60 degrees south, where everywhere on this track the Moon is garantueed to be in eyesight. Now I've not calculated on a slack of the wire.
It would probably be easier to build a track around whichever line of latitude can see the moon all year round than to build a tall tower strong enough to hold the cable.
02 Feb 09
1 edit
Originally posted by FabianFnas…Earth is tilted .…
The polar axis is tilted 23 degrees in respect to ecliptic. The orbit of the Moon around the Earth is tilted additional degrees. This means that the moon is not visible from the pole during half its orbit.
Mathematical excercize: How high must a tower be, at the exact south pole, so you can see the moon from its top all the time?
Yes -I forgot all about that for a moment.
07 Feb 09
Originally posted by twhiteheadAre you sure? I don't think it has ever been done because it is too difficult to manage that kind of electric surge. Once an electron path has been established the current slams all at once and fries everything in that path.
The reason the energy from thunderstorms has not been tapped is because it is far to inconsistent to be useful - unless you know a place that has 24 hour / day thunderstorms.
07 Feb 09
Originally posted by Metal BrainI don't believe that it does 'fry everything in its path'. With a good enough conductor it can be tapped. I rather doubt that large buildings have to replace their lightening conductor rods every time they get a strike.
Are you sure? I don't think it has ever been done because it is too difficult to manage that kind of electric surge. Once an electron path has been established the current slams all at once and fries everything in that path.
The main problem is that each strike is so brief that storing it is a problem and there simply aren't enough strikes in one spot to make it worth while trying to tap it.
07 Feb 09
1 edit
Originally posted by Metal BrainLet's do some moth here. One thing we want to know is how much energy (kWh) there is in one bolt of lightening, right? Is it worth to harvest energy from bolts at all?
Are you sure? I don't think it has ever been done because it is too difficult to manage that kind of electric surge. Once an electron path has been established the current slams all at once and fries everything in that path.
Okay, What we need to know before we do the mat is the following, and you have to help me to get these parameters...
How many Volts in one bolt?
How many Ampere in one bolt?
Myltiply and you get Watts during the bolt.
For how long does this happen? A second? A millisecond? Perhaps even a microecond? Or less?
Multiply the Watts with the Seconds and you get the Ws, this is the energy from one bolt.
Now convert Ws to kWh and see how much energy it really gives. I bet it is less than we usually think.
To do this calculation we need Volts, Ampere, and duration of one bolt.
There I need help.
07 Feb 09
Originally posted by twhiteheadLightning rods are pretty solid but even if the nanotubes can take the stress that does not prove you can tap into and use the current as a power source. How do you regulate the sheer force of the lightning bolt? I don't think it can be done in any practical way.
I don't believe that it does 'fry everything in its path'. With a good enough conductor it can be tapped. I rather doubt that large buildings have to replace their lightening conductor rods every time they get a strike.
The main problem is that each strike is so brief that storing it is a problem and there simply aren't enough strikes in one spot to make it worth while trying to tap it.
07 Feb 09
1 edit
Originally posted by Metal Brain-I once thought of a way!
Lightning rods are pretty solid but even if the nanotubes can take the stress that does not prove you can tap into and use the current as a power source. How do you regulate the sheer force of the lightning bolt? I don't think it can be done in any practical way.
You suspend an adapted Helium balloon high in the sky with a lighting cable attached that leads to the ground so that lighting is directed to that point on the ground. But the bottom end of this lighting cable on the ground is purposely suspended in a strong electrolyte such as very salty water so that the lighting passes through this electrolyte before going to ground. As it passes through the electrolyte, most of the electrical energy is converted into heat energy and heats the electrolyte. Heat insulation can be put around the container holding the electrolyte so that the heat can be stored and used gradually as and when required. The heat energy could be used to generate electricity for the national grid using a steam turbine or it could be used to heat hot water for people’s homes.
I once seriously wondered if it would be worth me making and patenting such a device but I think the amount of useful heat energy you can get out of it would be pathetic compared with our usual energy consumption + there may be no lighting strikes in an area for months at a time thus I concluded, just like with so many inventive ideas I have had in the past, it just wouldn’t be worth the bother.