However, on longer timescales the Earth-Moon system is not static. Tidally driven evolution of the orbits and spins of these two bodies results in a number of things. First, as we know well, the Moon's spin rate is matched to its orbital period so that it always has the same face to the Earth (except for some small librational wobbles). Second, because the Earth's spin is faster than the Moon's orbit, the tidal bulge raised on the Earth pulls on the lagging moon, gradually raising its orbit and slowing our day. Every year the Moon's orbit grows by some 3.8 centimeters and our day lengthens by about 0.000015 seconds.
At this present rate, in about 50 million years the Moon will never completely eclipse the Sun, it will simply appear too small on the sky. This orbital evolution also implies that total solar eclipses in the distant past would have been just that - completely obliterating the Sun from view. It is very likely that a scientifically minded Tyrannosaurus Rex never got to see the circle of fire, or Bailey's Beads in an eclipse.
So is there some great significance to the fact that we humans just happen to exist at a time when the Moon and Sun appear almost identically large in our skies? Nope, we're just landing in a window of opportunity that's probably about 100 million years wide, nothing obviously special, just rather good luck. (https://blogs.scientificamerican.com/life-unbounded/the-solar-eclipse-coincidence/)
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Date: 2022-10-31 06:54 am (UTC)At this present rate, in about 50 million years the Moon will never completely eclipse the Sun, it will simply appear too small on the sky. This orbital evolution also implies that total solar eclipses in the distant past would have been just that - completely obliterating the Sun from view. It is very likely that a scientifically minded Tyrannosaurus Rex never got to see the circle of fire, or Bailey's Beads in an eclipse.
So is there some great significance to the fact that we humans just happen to exist at a time when the Moon and Sun appear almost identically large in our skies? Nope, we're just landing in a window of opportunity that's probably about 100 million years wide, nothing obviously special, just rather good luck. (https://blogs.scientificamerican.com/life-unbounded/the-solar-eclipse-coincidence/)