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Comment by cperciva | Hacker News Reader

Related story for people who haven't heard about it: At one point CERN had problems which seemed to be related to the phase of the moon. After much head scratching, it turned out that the problem -- with an underground particle accelerator -- was indeed related to the moon phase, since the moon's gravitational pull was deforming the path of the particle beam.

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I've heard the same story about a telephone line in Marlborough: back in the black&white analogue times.

The story being that king tides were getting a connection wet near the shore and causing problems.

I wonder how they corrected it. By calibration, or carefully modeling the deformation according to the moon's mass?

Genuine question: how does the moon phase influence its gravity effect?

When the moon is full it is opposite the sun and reduces the effect of the sun’s gravity. When it is new it is in the same direction as the sun and increases the pull toward the sun.

Probably the same cause of tide supercycles - when moon and sun line up, the pull is additive. When they oppose, the moon detracts from the sun’s pull by a bit.

Writing that out I’m not sure it makes sense, but someone smarter will be along to correct me shortly.

I'm guessing it's more to do with the interaction of the gravitational vectors of sun and moon. During a half-moon it is pulling at a right angle to the sun, during a new-moon with the sun, and during a full-moon against the sun.

I guess they probably meant moon position in orbit, in general

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