Significance of equal Sun and Moon apparent sizes?

AI Thread Summary
The near equality of the Sun's and Moon's apparent sizes from Earth has primarily influenced mythology rather than significant physical effects on the planet. The Moon's distance from Earth has varied over time, while the Sun's distance has remained relatively constant, making the current apparent size coincidence. Calculations suggest that the Moon has been receding at an average rate of 3.8 cm per year, which would have made it appear larger in the past. For instance, one billion years ago, the Moon would have been about 38 million meters closer, resulting in a noticeable increase in its apparent size. Overall, the discussion emphasizes the cultural implications of this phenomenon rather than its physical significance.
Loren Booda
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How has the near equality of the Sun's and Moon's apparent size (as seen from Earth) affected our planetary history (vs transient phenomena like eclipses)?
 
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I believe its principal effect has been on mythology. As far as the physics of the earth, unlikely.
 
As the Moon's distance from the Earth has, over our double planet's history, changed quite a lot - and as the Earth's distance from the Sun has been pretty much constant - the apparent near-equality we see today is a curious coincidence in time.

Anyone got a reference (or want to do a calculation) on how the average angular size of the Moon (as seen from the Earth's surface) has changed in the last 500 million to 3 billion years?
 
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If we assume that the moon is receding at a constant rate of .038 m/yr, 1 million years ago, the moon was 38,000 meters closer. Compared to it's present distance of 3.84x10^8 m, the moon was closer only by a factor of 1.00009896. If today, the moons average apparent size is only 30 arc minutes, 1 million years ago, it would have subtended an additional .18 arc seconds.

A billion years ago, it would have been 38 million meters closer. A factor of about 1.1 times closer. It's apparent size would have been larger by about 3 arc minutes.

These calculations are probably wildly inaccurate in reality.
 
Originally posted by mathman
I believe its principal effect has been on mythology. As far as the physics of the earth, unlikely.

e.g., ancient astronomer's/astrologer's ability to predict eclipses was a source of political power. Maybe I can come up with some examples, L.B...
 
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