How the Moon Affects LHC Operations

[blixel]

I saw this article on /.

From the article, "Twenty some years ago, it then came as a surprise that, given the 27 km circumference of the accelerator, the gravitational force exerted by the moon on one side is not the same as the one felt at the opposite side, creating a small distortion of the tunnel. Since the moon’s effect is very small, only large bodies like oceans feel its effect in the form of tides. But the LHC is such a sensitive apparatus, it can detect the minute deformations created by the small differences in the gravitational force across its diameter. The effect is of course largest when the moon is full.

What came as a surprise to me was to witness the dynamic aspect of it. As the moon was rising in the sky, the force it exerted changed ever so slightly, but even these infinitesimal changes were big enough to require a periodic correction of the orbit of the proton beams in the accelerator to adapt to a deformed tunnel."

 

[John_L]

Why is a full moon more than a waxing or waning moon? It's all the same mass wise, it's just a matter of how much is illuminated or not. What am I missin' here?

Btw, cool find... a testament to the folks who constructed such sensitive equipment.

 

[Cras]

its opposite the Sun maybe? :shrug:

 

[NovaSilisko]

I'd imagine it has to do with the distance to the LHC from the moon.

 

[tblaxland]

Why is a full moon more than a waxing or waning moon? It's all the same mass wise, it's just a matter of how much is illuminated or not. What am I missin' here?

It is known as a spring tide and occurs approximately every two weeks when the Sun-Earth-Moon are in syzygy (ie, in a straight line, but only when looking at the system perpendicular to the ecliptic plane - the reason you can't just say "in a straight line" is that if you look at the system parallel to the ecliptic plane the three bodies are normally not in a straight line due to the inclination of the Moon's orbit). So, it is not just at full moon when the effect is greatest, but also at new moon.

 

[RGClark]

It is known as a spring tide and occurs approximately every two weeks when the Sun-Earth-Moon are in syzygy (ie, in a straight line, but only when looking at the system perpendicular to the ecliptic plane - the reason you can't just say "in a straight line" is that if you look at the system parallel to the ecliptic plane the three bodies are normally not in a straight line due to the inclination of the Moon's orbit). So, it is not just at full moon when the effect is greatest, but also at new moon.

So it is a combination of the Sun/Moon effects?

Bob Clark

 

[tblaxland]

So it is a combination of the Sun/Moon effects?

Yes.