<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Cole</i>
<br />If we are growing the moon should get farther from our surface year to year, which agrees with the data (almost 2 centimeters farther per year I believe).<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Actually, if our planet is growing, our surface would be getting closer to the Moon. However, the 2 cm/year is measured from Earth's center, not surface. So it has nothing to do with Earth expansion. Moreover, if Earth were growing in mass, that would force the Moon's orbit to shrink.
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Is that not correct? Shouldn’t the moon increase its distance if we grow, and shouldn’t we slow our rotation rate due to both an increase in our size and the consequent increased distance of the moon?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">An increase in Earth's size would slow rotation, but I don't see a way to use the Moon's increase in distance to support rotational slowing, other than through tidal friction. But if we say the Moon increases its distance because of tidal friction (**), then that slows Earth's rotation by itself, and there is little or no room left for slowing due to Earth expansion. -|Tom|-
(**) Details of tidal friction theory are in chapter 6 of my book. In brief, the Moon raises a bulge on the Earth. Earth's rotation drags the bulge ahead of the Moon. The bulge pulls on the Moon, speeding it up. And a faster speed makes the Moon's orbit bigger. Then the Moon pulls back on the leading bulge on Earth, which slows Earth's spin. (Tidal friction therefore has nothing to do with radial changes in distance, except indirecly. It operates by pulling the Moon forward, which is like a sling-shot effect that, as a secondary matter, increases the Moon's average distance.)
