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Originally Posted by Eroica
The reference was in the Recommended Reading section on page 261.
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Thanks! I found it in my copy. I must have read it before, but was confused with his BABB posts--I didn't remember seeing it before.
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Originally Posted by Eroica
I thought this amounted to what JohnD was saying in his "different orbit" theory. If not, I obviously misinterpreted it. Sorry again.
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I thought that the BA's version agreed with Sawicki's--and that JohnD's didn't. JohnD?
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I don't follow. At the moment that the point in question is closest to the Sun, it is travelling on an orbit about the Earth-Sun barycentre whose radius is less than that of the Earth's CoM by the radius of the Earth - not offset by the radius of the Earth.
Incidentally, why wait six months for it to be the farthest point? Isn't twelve hours just as good?
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We have to be careful here--the effect of the rotation of the Earth has nothing to do with the tides, so you have to do the analysis without regard to that rotation.
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It might be easier if we considered a situation in which the Earth is imagined to be travelling on a circular orbit and to be in a locked rotation, so that the point in question will always be closest to the Sun, and will surely be "orbiting" the Earth-Sun barycentre in a circular path, but at a speed that is too slow for free-fall.
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Of course, that means that the Earth rotates once per every revolution--and the effects you are describing are a result of that rotation, not the tide.