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Re: Tides without the Moon
From: Frank Reed CT
Date: 2003 Dec 24, 03:10 EST
From: Frank Reed CT
Date: 2003 Dec 24, 03:10 EST
"would a moonless earth have significant tides? "
Yes. The solar tides on average are about 40% of the lunar tides. So you would still have plenty of range in the semi-diurnal tides if there were no moon. There would be much less daily, weekly, and monthly variation in the tidal range. Also, tides from a single source cause tidal locking (synchronous rotation) much more rapidly than tides from two sources. I am only speculating here (I haven't run the numbers), but the Earth's rotation might be significantly slower today if the Sun were the only tide-producing body.
"How great a fluctuation might there be in a Bay of Fundy-type place"
Fundy tides occur when the natural frequency (frequencies really) of the body of water match the driving force. That's resonance. If the Sun were the only source of the tidal driving force, you would not get the same resonant matching at the same locations, but you would get resonant matching at some other locations. I haven't seen a detailed account of this, but I am sure you know that the distribution of land masses on the Earth has changed dramatically in the past couple of hundred million years (and that's just a small fraction of the total age of the Earth). The present distribution of land, especially along the Atlantic is more likely to produce resonance than the distribution of land in the Pangea days. Would't it be fun to have a tide table for Brontosaurus? It's almost possible with wat we know today.
And you asked:
"and how great a fluctuation in areas with lesser tides, such as the coast of South Carolina?"
Off-resonance tides, like those on most of the US East Coast, would not be all that different. Smaller range, yes. Same solar time every day instead of correlated with the Moon's transit, but otherwise not much different.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
Yes. The solar tides on average are about 40% of the lunar tides. So you would still have plenty of range in the semi-diurnal tides if there were no moon. There would be much less daily, weekly, and monthly variation in the tidal range. Also, tides from a single source cause tidal locking (synchronous rotation) much more rapidly than tides from two sources. I am only speculating here (I haven't run the numbers), but the Earth's rotation might be significantly slower today if the Sun were the only tide-producing body.
"How great a fluctuation might there be in a Bay of Fundy-type place"
Fundy tides occur when the natural frequency (frequencies really) of the body of water match the driving force. That's resonance. If the Sun were the only source of the tidal driving force, you would not get the same resonant matching at the same locations, but you would get resonant matching at some other locations. I haven't seen a detailed account of this, but I am sure you know that the distribution of land masses on the Earth has changed dramatically in the past couple of hundred million years (and that's just a small fraction of the total age of the Earth). The present distribution of land, especially along the Atlantic is more likely to produce resonance than the distribution of land in the Pangea days. Would't it be fun to have a tide table for Brontosaurus? It's almost possible with wat we know today.
And you asked:
"and how great a fluctuation in areas with lesser tides, such as the coast of South Carolina?"
Off-resonance tides, like those on most of the US East Coast, would not be all that different. Smaller range, yes. Same solar time every day instead of correlated with the Moon's transit, but otherwise not much different.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
