A mad scientist decides to hold the moon hostage for one million dollars. He accomplishes this using a tractor beam of arbitrary power to trap the moon directly between the Earth and the Sun. The tractor beam is indestructible, will not drift in respect to the Solar System, etc.

A side effect of the tractor beam is that it warps space around it, causing the sun's light to lens around the frozen moon and reach the Earth just the same as it does right now (except there's a big ol' moon-shaped hole in the middle). This is intentional, as the mad scientist does not wish to end all life on Earth just yet.

But what effect does this have on the Earth? Presumably, we will no longer have tides, just as if the moon had been destroyed. Would there be any other effects? Would there, in fact, be any difference between this scenario and destroying the moon outright?

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    $\begingroup$ If the moon is locked along the line segment described by the sun and Earth, there will be tides as the Earth rotates between day and night, won't there? Always high tide at noon, low tide at midnight. $\endgroup$
    – Ranger
    Oct 3, 2016 at 19:01
  • $\begingroup$ Also the myth that the moon only comes out at night will be forever abolished. $\endgroup$
    – Ranger
    Oct 3, 2016 at 19:02
  • $\begingroup$ A solar eclipse only makes a tiny dark spot on earth, with a somewhat larger area around it in the penumbra. en.wikipedia.org/wiki/Solar_eclipse#/media/… No need to warp space I think i will make your mad scientist pay me a few dollars before i take the moon back. He'll soon be faced with an arbitrarily large electricity bill, though, so it's no use to be too greedy. $\endgroup$
    – Karl
    Oct 3, 2016 at 22:54
  • $\begingroup$ That sounds like a terrible return on investment to me. The cost of the technology to pull off something like that would likely exceed his million dollar ransom by a factor of at least 50. $\endgroup$ Oct 3, 2016 at 23:39
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    $\begingroup$ The scientist is mad, not business-savvy. $\endgroup$
    – SPavel
    Oct 4, 2016 at 2:18

2 Answers 2


Presumably he waits until the moon is approximately between the sun and Earth before activating his plot device? The moon doesn't pass directly between them very often, because when it does, that creates a solar eclipse. But since his device avoids Earth becoming colder, that isn't a major concern.

The effect on tides is interesting: all tides are spring tides, because the sun and moon are always pulling in the same direction, which may mean that some low-lying areas flood more often, because there's always a spring tide when storms happen, rather than a flood requiring the combination of a spring tide and a storm.

Earthquakes may become slightly more common, because they are sometimes triggered by the tides in the "solid" body of Earth. Yes, this really happens, it just isn't very obvious.

But overall, this isn't too horrible. It's a good thing that his ransom demand is quite small, because if it were much larger, he might well get a reaction of "Nah ... this isn't too bad." He might be better off selling his invention, and just stopping the moon as a demonstration that it works. It probably has substantial peaceful applications, given that it clearly breaks the laws of conservation of energy and angular momentum.

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    $\begingroup$ I agree, except for one point. I think the mass panic and obvious, literally daily reminder of a madman with that much power would be worth investing far more than a simple million into taking care of. The Iraq war cost over $2 trillion, and 9/11 was far less visible to America than a locked moon and daily solar eclipse. $\endgroup$
    – Ranger
    Oct 3, 2016 at 19:23
  • $\begingroup$ How many alternative explanations would appear? Religious, conspiracy, "new age", astrological, etc. ones seem likely. How many people actually understand how the moon and tides work? It's a threat that only matters to people who have some knowledge of astronomy and take it seriously. $\endgroup$ Oct 3, 2016 at 19:30
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    $\begingroup$ I'd argue if I stuck a moon-sized neon board with the word "fart" on it appeared in the sky, looming over the world each day, I'd create mass panic, and nobody would have knowledge to explain that. You don't need knowledge to panic. $\endgroup$
    – Ranger
    Oct 3, 2016 at 19:33
  • $\begingroup$ @NexTerren I don't think people will panic over that. Confused? Yes, but there's no recognizable threat from that. $\endgroup$
    – Nelson
    Oct 4, 2016 at 3:53

It would seem there would be no serious change. The same amount of light is lensing around the moon to reach the Earth's surface, and tides would continue (though the schedule would change) as the Earth rotates below the moon and its gravitational pull is unchanged. (Don't forget the sun accounts for ~46% of tide height.)

There would be an eclipse moving across the planet in a narrow band, affecting a small area in the umbra of the moon. The eclipse would last minutes.


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