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To: dr_lew
You are replying to a post which is actually continued from post #49. In post 49 I show that the gravitational force exerted by the Earth is roughly 29 million times greater than the force exerted by Jupiter. In that post I mention that you could double Jupiter and see a gravitational effect on the order of 1/10,000,000, that effect would be many times greater than the additional alignment of Pluto.

Someone naturally speculated what the actual effect of even more distant Pluto would be. The answer is that it is about 20 million times weaker still.

The speculation in this article -- while wildly wrong -- does not involve tidal forces.

The tidal force is not a differential adjustment in the gravitational effect on nearby points, which is almost always negligible. [It goes as -2dr/r. For the moon, the effect on points separated by 1m is 2 parts in 300,000,000. This is not even detectable. So slightly displaced doesn't cut it.]

The tidal effect arises because for bodies of large spatial extent, there are measurable differences between the gravitational attraction on opposite (or even widely separated) parts of the object. For the moon, the maximum effect is around 6/300. At 2% it is not negligible, but the most dramatic effect is observed at 12,000 Km apart. That's not slight displacement, even when considering LD as a unit of measure.

86 posted on 12/28/2013 6:56:56 PM PST by FredZarguna (Nobody so soundly whipped is entitled to a rematch.)
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To: FredZarguna
The tidal force is not a differential adjustment in the gravitational effect on nearby points, which is almost always negligible. [It goes as -2dr/r. For the moon, the effect on points separated by 1m is 2 parts in 300,000,000. This is not even detectable. So slightly displaced doesn't cut it.]

The "-2" in -2dr/r is the -2 in the tidal tensor and represents the stretching effect along the axis of attraction, as represented by the first order term of the power series expansion.

The displacement is considered "slight" in the sense that the first order term is much larger than higher order terms.

Also, whether one uses higher order terms or not, the whole treatment is of a differential force.

The speculation in this article -- while wildly wrong -- does not involve tidal forces.

It says, " This rare alignment will mean that the combined gravitational force of the two planets would exert a stronger tidal pull, ..." Sheesh!

96 posted on 12/28/2013 8:04:11 PM PST by dr_lew
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