For RichardT: Focault’s Pendulum

I was recently reading one of the threads here where RichardT was explaining that he thinks that the earth never moves, and the sun revolves around it, and it made me wonder what he thinks of Focault’s pendulum. This is a device that was invented by the physicist Léon Foucault, in order to demonstrate the rotation of the earth.

The way this works is that you get a huge pendulum that can swing freely in any direction, and set it swinging in a straight line back and forth. They usually launch one of these by holding it to one side with a string and then burning the string, in order to make sure nobody accidentally imparts any sideways momentum to the pendulum. Pendulums always swing back and forth in a single line, so if the earth were standing still, this one would just continue swinging in a single line relative to the ground. But Focault’s Pendulum doesn’t do this—the path of its motion slowly rotates relative to the ground. Since physics don’t allow for the path of a pendulum to rotate on its own, when the path of this one rotates relative to the earth, it can only be the earth that’s rotating.

There’s an article about these devices here, along with a diagram of showing how the motion of the pendulum will appear to change over time. (Although this is obviously quite a bit faster than the speed it would change in real life.) If you make one of these at the North Pole, it will look like the path of the pendulum is rotating clockwise, but it actually isn’t—the pendulum is swinging back and forth in a straight line, and as you stand on the earth while it rotates counter-clockwise, this is how it looks.



I’ve seen one of these in person at the Franklin Institute in Philadelphia, and they periodically set up little metal pillars on the floor under it so that the pendulum will gradually knock them over as its path rotates. It’s possible to determine what time of day it is based on which of them have been knocked over.



I’ve noticed that lately the members of this board have been tending to just mock Richard for what he believes about this rather than trying to educate him, so I’d like to try showing him how it’s possible to physically observe earth’s rotation. When a direct observation like this contradicts your interpretation of the Bible, doesn’t that mean you’re understanding the Bible incorrectly?

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“If one accelerates a heavy shell of matter S. then a mass enclosed by that shell experiences an accelerative force. If one rotates the shell relative to the fixed stars about an axis going through its center, a Coriolis force arises in the interior of the shell, that is, the plane of a Foucault pendulum is dragged around."

-- Letter from A. Einstein to E. Mach.

There is no net force in a stationary shell of matter, but since the universe would go through a daily rotation, that is what would cause the pendulum to swing.



http://www.geocentricity.com/ba1/no71/selbrede.html

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You will do me the justice to remember, that I have always strenuously supported the Right of every Man to his own opinion, however different that opinion might be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it.

-- Thomas Paine

Where is this matter? I have heard this explanation from the geocentrists but I don't think it works because of the inverse square law of gravity the "heavy shell of matter" would seem to me to be too far away to generate the required effect for either Focault's pendulum or the Coralis force. If I am wrong please show me the quantitative calculations to prove it.

Added in Edit: But I would prefer you answer my questions in the other thread first.

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A little Learning is a dang'rous Thing;
Drink deep, or taste not the Pierian Spring:
There shallow Draughts intoxicate the Brain,
And drinking largely sobers us again.

Alexander Pope

I don't know the calculations. I should know them but I don't. If you want, you could email Dr. Bouw, he is the professional astronomer after all.

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You will do me the justice to remember, that I have always strenuously supported the Right of every Man to his own opinion, however different that opinion might be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it.

-- Thomas Paine

Interesting, a thread on the Focault Pendulum. Back when I was a physics major in college, two of my classmates actually decided to do this for their junior year project. It actually rotated ten times too fast, and in the wrong direction. Methinks all the fancy electronics got in the way of the physics...but that's another story.

I actually do know the calculations, Richard. The explanation wouldn't work. The Foucault Pendulum operates by means of the Coriolis force (which I'm sure you're familiar with from reading geocentrist apologetics). The Coriolis force is found from the cross product of the angular velocity of the reference frame and the translational velocity of the moving object, i.e. it is perpendicular to both quantities, but the angular velocity doesn't vary. This is why the Coriolis force on the pendulum changes direction every half-swing. But if the earth were stationary, then this would necessitate that the Coriolis force on the pendulum bob is always zero. Alas it isn't, which means that the geocentrist argument you provided earlier is wanting.

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Whoever believes in him is not condemned, but whoever does not believe is condemned already, because he has not believed in the name of the only Son of God. (John 3:18)

As E. Mach, H. Thirring, P. Gerber, J. Lense et. al. have shown, a rotating shell of matter would account for these forces. Follow the calculations yourself. Show me the faults in these.

Thirring, H., 1916. Phys. Z. 19:33.
Lense, J. & Thirring, H., 1918, Ibid. 22:29.
Gerber, P., 1898. Zeitschr. f. Math. u. Physik, 43:93.

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You will do me the justice to remember, that I have always strenuously supported the Right of every Man to his own opinion, however different that opinion might be to mine. He who denies to another this right, makes a slave of himself to his present opinion, because he precludes himself the right of changing it.

-- Thomas Paine

RichardT, it has already been shown that a rotating shell of mater presents problems for spacecraft, stellar parallax, red shifts, orbits, and just about everything that is more than a few miles above the Earth’s surface.

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Goodbye all.

Only if you don't ignore all that first by pretending really, really hard that all that isn't true.

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FAITH, n. Belief without evidence in what is told by one who
speaks without knowledge, of things without parallel.

The Devil's Dictionary, By Ambrose Bierce

See, this is an example of the sort of thing that annoys me here. Not that you’re doing it any worse than some of this board’s other members, but I just mentioned this in my OP.

In 2004 and 2005, it happened pretty often that people would join this board who were creationists just because they’d never been properly educated about science. Since they were willing to learn from the regular posters here, they would usually end up becoming theistic evolutionists within a few months. RichardT isn’t any more stubborn or less intelligent than any of the people like this we’ve had in the past, and around the beginning of this year some of the other members were pointing out that things were going the same way for him that they’d gone for all of the other creationists here who eventually accepted evolution. The only thing that’s different in his case is the way people here have been treating him lately, and as far as I can tell this is the reason why he’s still a creationist and a geocentrist.

Richard, I have another question for you about this. If the earth isn’t rotating, how are geostationary orbits possible? A geostationary orbit is when a satellite’s orbit around earth is such that its position relative to earth’s surface never changes; this is what’s used for things like TV satellites.

http://en.wikipedia.org/wiki/Geostationary_orbit

If earth is rotating, that means these satellites are orbiting around earth at the same rate that earth is rotating, whereas if earth is standing still, that means these satellites aren’t moving at all. But satellites have to move in order to remain in orbit—the reason they’re able to stay in orbit is because their centripetal force counteracts earth’s gravity. If earth isn’t rotating, and satellites in geostationary orbit aren’t moving at all, what’s preventing them from falling out of the sky?

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Richard,

I am not an expert on GR but I do know some physics and math. I suggest you reread Thirring and Lense and Thirring. Be sure to actually read and study the papers and not just accept what the geocentrists say about them. I don't think they are actually saying what the geocentrists claim they are saying. In fact the Lense-Thirring effect apparently acts on artificial satellites because of the rotation of the earth. This effect is being studied by NASA.

__________________
A little Learning is a dang'rous Thing;
Drink deep, or taste not the Pierian Spring:
There shallow Draughts intoxicate the Brain,
And drinking largely sobers us again.

Alexander Pope