It’s year 2050 and within 10 years, all fossil fuels will be used up. All countries signed an agreement to approve an international construction, described as follows:

  1. A track will be built on the equator, so something like a round railway will be constructed. It’s flat, so mountains on the equator will be flattened. Part of the seas/oceans will be reclaimed. It’s almost frictionless, so wheels can move on it easily. A similar track will be constructed on the Moon.

  2. Solar panels are placed on the Moon, covering over 90% of its surface. The remaining area is used for maintanence, as well as the track.

  3. A thick (perhaps, really thick) wire is constructed, perhaps with the help of airplanes, satellites and space shuttles, so that the tracks on the Earth and the Moon are connected. The wire may look like a thick pole when viewed on Earth, but when we scale down everything it should look only something like a set of electrical wires. At the two ends, wheels are installed, so the wire can move on the track like a train.

  4. All materials used conduct electricity (perhaps with a plastic coating if there’s any safety concern).

  5. All countries are going to work together, so money is (probably?) not a concern, and selling electricity earns money anyway.

  6. All countries have the responsibility to maintain the system. I assume that no one deliberately damages the system.

  7. Flying organisms around the wire are monitored, so they will be killed or brought away before getting close to the wire.

  8. It’s up to the civil engineers of this project to decide the details of the system, for example, how wide the track should be, how thick the wire should be, etc. All of them are well-educated.

  9. There is no aesthetic concern, so it’s okay for the system to look ugly as long as it supplied electricity.

Is this feasible? Any practical difficulties that we are unable to overcome?

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    Not even a little bit, especially not until 2060. But why do you care? Just do it. It's a good sci fi premise. If fiction had to be real, we wouldn't need fiction, entertainment would just be reading protocols of things that happened. Look at popular shows: Star Trek, Star Wars, Star Gate, Battlestar, Handmaid's tale (if you're into boring stuff), the Rick and Morty, Firefly, nothing there makes sense, but it doesn't matter, it's still enjoyable to many people – Raditz_35 Aug 13 at 9:27
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    @Raditz_35 Firefly was imminently sensible. They turned off the thrust when up to speed, were always worried about running out of fuel, weren't interstellar, etc. The only serious handwavium was artificial gravity. – RonJohn Aug 13 at 10:07
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    "Is this feasible?" Absolutely not. "Any practical difficulties that we are unable to overcome?" Items 1-8 are either wrong or impossible. – RonJohn Aug 13 at 10:11
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    I'd give up trying to make it sound reasonable for 2050. Make it the year 2500 and propose entirely fictional materials. The wire could be some kind of lattice (like a Chinese finger trap) so it can grow longer and shorter as the moon moves in and out. Or maybe people have literally moved the Moon into a more convenient orbit. – Joe Aug 13 at 16:08
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    What about, instead of a wire, you use the concept of wireless transmission of electricity? Doesn't seem too far-fetched with some hand-waving involved. Then you could still have huge solar panels on the moon that wirelessly transmit power back to Earth. – ell Aug 13 at 17:43

10 Answers 10

up vote 20 down vote accepted

Yes, it is possible!

Maybe not in 2050-2060 and not according to your design, but yes, it is possible to connect the Earth and Moon using scientifically plausible methods.

The main stepping stone to this project would be building practical Space elevator. This will get us a "wired connection" from Earth to at least a geostationary orbit (35,000 km) altitude. Second step would be building similar elevator on the Moon. According to this answer, "moonstationary" orbit has an altitude of 52,700 km. Those two elevators are still way short of the average distance of about 385,000 km between Earth and Moon.

Creating a free wheeling platform will be another engineering challenge. The original design with sea level rails around equator is not very practical, because, as L.Dutch had pointed out, rail platform will need to travel at supersonic speeds, and there would be no way of concealing it in some sort of hyperloop-type structure. That's why I'm proposing lifting this construction in space. This will be very similar to an Orbital ring, and platform would be able to move freely outside of thickness of Earth atmosphere.

Next challenge would be connecting the wheeled/maglev platform with lunar tether. As we see from an orbital configuration scheme, we just can't connect Earth and Moon with a tightrope.

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So, the cable that connects Earth's space loop platform to lunar stationary tether need to have some slack. The distance between Earth and Moon varies between 360,000 km and 405,000 km. Subtracting space elevators lengths, space cable length has to vary between 272,000 km and 317,000 km (or less, because space elevators counterweights would be at higher elevation than geo/moon stationary orbits). Earth/Moon orbital configuration mismatch should add no more than 1,000 km to the estimated length of the cable. We either will have some 45,000 slack of the cable floating in space, or design "spooling stations" which would be pulling and releasing cable as needed.

  • This is an excellent re-imagining of OP's idea without (much) hand-waving and without just saying "no" – Fred Stark Aug 14 at 4:02
  • The largest obstacles are getting a material with enough specific strength (carefully tapering it helps, but you can only make it so thick on the thickest part) and stabilizing the orbital rings, because the connecting cable will try to pull them to the Earth (as the larger body). – Jan Hudec Aug 16 at 5:25

Shortly said: no.

Longer said:

The latest What If answered a very similar question to yours, stating that it is not possible, for various reasons:

In real life, we can't put a metal pole between the Earth and the Moon. The end of the pole near the Moon would be pulled toward the Moon by the Moon's gravity, and the rest of it would be pulled back down to the Earth by the Earth's gravity. The pole would be torn in half.

This is apparently solved by your railway, but then you have to consider that

The Moon doesn't always stay the same distance from Earth. Its orbit takes it closer and farther away. It's not a big difference, but it's enough that the bottom 50,000 km of your fire station pole would be squished against the Earth once a month.

And

The Moon's orbit is tilted by about 5° relative to the Earth-Sun plane, while the Earth's axis is tilted by 23.5°. This means that the Moon's latitude changes the way the Sun's does, moving from the northern tropics to the southern tropics twice a year.

Finally

Asking how fast the pole is moving relative to the surface is effectively the same as asking what the "ground speed" of the Moon is. This is tricky to calculate, because the Moon's ground speed varies over time in a complicated way. Luckily for us, it doesn't vary that much, it's usually somewhere between 390 and 450 m/s, or a little over Mach 1, so figuring out the precise value isn't necessary.

So, in your concept you have a 380,000 km long pole moving at Mach 1 on a trajectory which moves constantly around the Equator and has also to accommodate for the variation in distance between the Earth and the Moon.

If you want to transmit energy from the Moon, better invest in microwave (or any other EM waves for which our atmosphere is transparent) focused beams which is less sensitive to the listed problems.

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    I was about to write up an answer going in a very similar direction. As an alternative for the wire & train track I would have suggested a giant laser array on the moon with multiple receiver stations on earth. – Nicolai Aug 13 at 9:33
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    The biggest arguments against using a Microwave beam for power transmission are that a) it cooks everything that enters the beam, picture birds flying into the beam and exploding and b) because of the previous, what you've actually created is a Kill-Sat that can flash-fry cities and towns anywhere on the planet at zero notice. Nobody sane would want to put that kind of power in the hands of another human being, let alone another nation. – Ruadhan Aug 13 at 12:03
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    There's a marvellous Asimov Robot story, called "Reason" that involves solar power satellites, and robots who manually hold the microwave beam on guide as the slightest deviation could devastate hundreds of kms of earth if the beam drifts off the receiver station. Without spoiling the story, the fact of what the beams do is both central to the plot and entertainingly irrelevant to it at the same time. – Wenlocke Aug 13 at 13:43
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    The solution would be given by its very technical limitations: there's no way to build a laser that powerful, nor any receiver who would not melt instantly on the other side, so instead of an epic comic-supervilliain weapon you end with several thousand huge lasers which could greatly increase the temperature of the atmosphere above a city the size of London - I doubt you could aim anything smaller, due to laser scattering in the atmosphere - but no nation would surrender the control of ALL of the lasers to a single entity. – Rekesoft Aug 13 at 14:43
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    One additional point that you didn't address: The moon is tidally locked, which means that the same face always faces the Earth. Therefore, an equatorial railway is not needed on the Moon, because it does not rotate with perspective to the Earth. – GalacticCowboy Aug 13 at 15:07

Let me Propose a solution close to your pretense:

Instead of a wire, use a LASER and a receiver. They coulds still be gigantic constructions, serving the same or at least a very similar Story-purpose as a big wire.

It might be as or even more efficient, and far more feasable/believable. We can do that even today in smaller scale. For reference look here: https://en.wikipedia.org/wiki/Wireless_power_transfer#Microwaves_and_lasers

As was suggested you can build multiple Recerver stations. (as Alexander pointed out the railsystem would still not be feasable)

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    The rail system wouldn't take away significant area for solar power on earth, being just a 1-dimensional line. The problem with it would actually be the stupidly expensive tracks, in particular across the oceans. Fortunately the rails wouldn't be needed with a laser or microwave transmission, since that can simply track stationary receivers on Earth. – leftaroundabout Aug 13 at 14:02
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    You get points because lasers are cool, and Moon lasers even more so. – AmiralPatate Aug 13 at 14:08
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    Indeed it won't be as efficient--it'll be more efficient. Resistive losses over a wire of that distance would make the whole pointless, even if the material technology were there. – Logan R. Kearsley Aug 13 at 18:40
  • I did further research and will edit my answer, thanks! I was worried about the Energy lost between the Dishes and forgot the resistance of the wire. – Kweb Aug 14 at 8:27
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    @LoganR.Kearsley: actually, it's feasible electrically, you'd need 3 wires, about 250mm (10") in diameter. Transmitting at 120MV (it's a vacuum for most of the way, you could potentially go higher) would net you about 3% losses on a 2PW transmission. – IronEagle Aug 14 at 16:10

Not even close - the electrical reasons

No one seems to have addressed the manifold issues with attempting to transmit electrical power over such a distance.

First, you can't transmit electric power with only one cable, you need at least two. Modern transmission often uses three or more.

The cables could be almost impossible to produce. It has to be strong and it has to conduct electricity very well - at such lengths, every nanoOhm of resistance adds up to a huge amount. It also has to handle extremely high voltages/impedances. The cables would certainly have to be very thick, and they would be very expensive. Frankly, I can't imagine how any material could be made that would withstand the forces this cable would endure, and for such a material to also have a low electrical resistance seems beyond belief.

Suppose we have magic cables and there are only two of them. Likely HVDC (high voltage direct current) transmission is the only feasible option. Luckily this means no conversion at the source, since solar panels produce DC current. We will forget about conversion challenges on Earth on the assumption that they could be overcome if the cable could work.

In order to make the transmission at all effective, a very high voltage would have to be used on the transmission cable, and a lower voltage would be present on the return cable. As an old radio engineer once told me, "at 10,000 Volts, everything is a conductor". The point being, putting "plastic" on these cables would do nothing to make them safer. They would have to separated by a decent amount of air for the earth-based portion, and some space in space. Likely they would have to have spacers made of some kind of ceramic between them to keep them the required distance apart for such a long distance.

Now you have a huge cable with kV of electric potential in it circling the globe at Mach 1. Keeping wildlife away from it would be ridiculous. The wildlife wouldn't have anywhere near the time to get out of the way. Hopefully they would learn to avoid the path of the cable very quickly.

Getting back to electrical issues, the movement of the cable through the air at such a speed would cause it to heat up, increasing its electrical resistance which would cause more heating, but there would be no such effect outside of the atmosphere, so we have two sections of huge long cable that have very different electrical characteristics. Basically it would have to be two types of cable joined together somewhere around the altitude where the air gets a bit dense. I can't even imagine the challenges of such a joint.

The amount of the Earth's surface that would have to be used for cable track and safety margins is probably great enough that a better option would be to just cover that much of the earth with solar panels!

  • Cable /= conductor. Most cables contain several conductors. – Paul Johnson Aug 14 at 18:03
  • @PaulJohnson I'm not sure where you're going with your comment. If you're suggesting that one cable with two conductors could be used, it is highly unlikely or impossible or at least impractical. Somehow you'd have to insulate the cables from each other. There is a cost-effective insulator that requires the least amount of material between conductors to prevent arcing given a voltage difference, and that insulator is air. So the best way to insulate the power line from the return line is to make them two separate cables with a gap in between. – Todd Wilcox Aug 14 at 18:17
  • @PaulJohnson Remember, "above 10 kV, everything is a conductor". At a certain potential difference, electricity can arc over thousands of feet. That's what lightning is. So that gives us an idea of the kinds of limits there would be on the voltage difference that can be maintained between the two conductors. Such a voltage limit suggests that there is no way to reasonable transmit power from the moon to the earth, regardless of the materials or geometry of the conductors. – Todd Wilcox Aug 14 at 18:18
  • @PaulJohnson It looks like PET and Teflon can have several orders of magnitude greater electrical resistance versus air. Normally it's cost that prevents their use as insulators/dielectrics in high voltage electric power transmission. Supposing cost is not a factor in this question, there are still the issues of weight, construction, flexibility, and all kinds of other materials properties. Perhaps only the portion of cabling within the atmosphere would be covered with Teflon, but that's still a lot of Teflon and doesn't solve the problem of heating due to air resistance. – Todd Wilcox Aug 14 at 18:36
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    Remember that about 378,000 of the 380,000km to the moon is away from any moving manmade objects and in a vacuum. So insulation for most of the run could be handled by the vacuum, and you could step it down to a lower voltage once you near earth. Also, the surface area of the moon is the same a about 1/4 of the total land area on Earth, so.... putting them on Earth might not be an option. But, to get a reasonable 50PWh a year, you only need about 1/350th of the moon covered, so... – IronEagle Aug 15 at 14:20

Is a physical connection actually necessary? If you were to build a huge wire system along the lunar plane, why not make the wire system all coated copper wire. Then you install an incredibly powerful magnet on the moon. With enough copper wire you could make a whole lot of DC electricity just from the motion of the moon itself.

While being a somewhat elegant way to generate electricity, The questions of how to construct such a powerful magnet, and where to get that much copper (there's probably not enough on earth) would still be major dilemmas.

  • Yes, with the motion of the moon, the solar panels are unnecessary. Plus, transmitting electricity over such a distance - I can't imagine the electrical engineering problem that poses. – Todd Wilcox Aug 14 at 15:42
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    Actually, I ran through the numbers, and electrical engineering wise, the cable could be as small as three 10" (250mm) silver cables. Which could transmit all of the 2PW you would get (even though the forecasted energy usage in the 2050's would be about 1/10th of that) with about 3% losses at 120MV. The silver would cost about 300 trillion USD in today's money. – IronEagle Aug 14 at 16:07
  • @IronEagle That seems surprisingly doable! how powerful would the magnet have to be? – Widea Aug 15 at 18:33

Ignoring the other problems that other answers have covered, I'd like to mention a couple of problems that haven't been talked about.

1) Friction: You said that you'd somehow have a friction-less track. Even if this were a hover train or you somehow reduced friction to near zero with wheels, wind resistance would be a major problem. You would have a train going around at about mach 1 (the speed of the moon) on this track. It might take much of the power being sent just to maintain the velocity of the train.

2) Electricity transportation over long distances. This is sort of the same type of resistance problem as above, but with electricity. Google "problems transmitting electricity over long distances" to learn more. Even over short distances energy can't just go through wire without losing some of its power, mostly in the form of heat generated and being dissipated.

You could overcome these resistance problems with some sort of magic-wand waving fictional thing. Even better than ignoring those problems would be to mention the problems and either how they were solved or accounted for, or else have them be a real problem that affects the plot, if only in a small way.

For example, the atmosphere of earth becomes increasingly hot because of the energy being dissipated from the wire. Or, because of the friction not being quite zero, over time the moon and earth's orbits are actually altered somewhat, and that starts to cause problems.

  • resistance becomes less of a problem with increased voltage: since most of the transmission (379,500 of the 380,000 km) is in a vacuum, you could easily up the voltage to 120MV, or about 100x the current highest voltage used for transmission on Earth, and end up with about 3% losses on a 2PW transmission. – IronEagle Aug 14 at 16:14

Your premise that all fossil fuels will be gone by 2060 on earth seems maybe the most far fetched. Also that you can somehow build all these solar panels and two huge tracks and ship most of it to the moon in just a 10 year period.

If your premise was that earth figures that they only have 300 years of fossil fuels left, (I'm just making up a number that's more believable, I have no idea the real number, which you should actually research), and they somehow all come together in a coalition to solve the problem for their children's children's children's children (again, very unbelievable), it would actually take up all those fossil fuels to build this stuff. Solar panels don't get created without using fossil fuels. Big tracks don't get created without fossil fuels. It would be an earth-altering project for sure (and pretty unbelievable).

It would all be much more believable on a distant earth-like world. You could fix all sorts of problems that way. You could have their moon(s) be in the proper orbit, you could even reduce air resistance and gravity and all sorts of issues by not having your story take place on earth. Even put the civilization on a moon and have the orbiting power be satellites or other small harvested asteroids or moons. Make it enough like earth so that people identify with the characters and issues, but less like earth so you can fix all the scientific problems. The key is to recognize that there are definitely problems and not just ignore them completely. That doesn't mean the problems have to be front and center in your story, but if they aren't addressed a little bit then it isn't believable.

The real question is what energy source are you getting on the moon that you can send back to the Earth?

Solar isn't really viable because you still have light and dark phases. You'd just make solar satellites that get light 24/7 and beam the light back to Earth at the poles.

The most likely energy source you can get from the moon is helium 3 which can be mined from the moon and sent back to Earth to use in fusion generators

This is the basis of the movie Moon

If you want your wire to space, just have it as an space elevator that collects the H3 sent from the moon.

Your plan is going to fail. The distance between the moon and the earth is not fixed and nor is the spot of connection. If you really want to build upon this approach, a more feasible solution will be to build a system of solar panels in space facing the sun. There will be 100% utilization of solar panels in this system rather than 45% since only half of the moon faces the sun at one time. You don't need to make a pole as long as moon distance. You just need to take them high enough to leave the earth's atmosphere so that you don't have to deal with air resistance. You may have to counter celestial gravity and space debris though.

Don't worry about physical limitations or impracticalities. This is fiction. It doesn't need to be a blueprint for something in the real world. It only has to be enjoyable and understood by the reader.

Go with a physical link, if that's what you want. Or use a wireless link (think Tesla Tower or shield generator from Endor to the Death Star).

If all science fiction required a solid and feasible grounding in fact then we wouldn't have many science fiction books/films to enjoy.

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    You can invent stuff in fiction world, but it still has to make sens when given proper explanation. You cannot hand wave the basic physic laws and call it a day, because then your story will be too much of a non sens. Even when you create a totally non-earth-like new world, you have to explain what are the rules and the limitations of this world. – Ankinou Aug 13 at 11:54
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    Also, working out what is broadly feasible or logical given some requirement is pretty much what this site is for. If the answer is always 'yeah, whatever!' then we can just all go home. – Phil H Aug 13 at 12:04
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    "Don't worry about physical limitations or impracticalities" No. Just, NO. This is near to impossible, as L.Dutch prove it. And he don't even bother answer to how much material is needed, or can all the countries work on the same project. It's so unprobable that it can really ruin the whole thing: reading a story that handwave such thing, i would know that not only I read a fiction, but I read a bad fiction. – Kepotx Aug 13 at 12:24
  • To be clear, my comment doesn't say "go with the impossible". It was more encouragement to flesh out the whole idea without getting hung up on one detail - which may or may not end up in the final edit. – suchafunkymonkey Aug 13 at 13:27
  • If yours is a comment as you state, write it as such, and not as an answer – L.Dutch Aug 17 at 13:16

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