How did the Moon end up with an orbit the perfect distance to cause total eclipses?
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This is one of those (to our current understanding) coincidences that religious people like to use as ammo in the intelligent design theory.
Who knows maybe one day they’ll be proven more correct than current science suggests!
It doesn’t always cover the sun.
Last Saturdays eclipse was not total but the moon was completely in front of the Sun , leaving a nice solid solar ring around the moon (not the bright diamond ring kind you get with a total eclipse but a solid circle of the sun around the shadow of the moon) . I assume that this is an effect of the variable distance between the Earh, the Moon, and the sun.
Short answer: it didn’t. The Moon’s orbit is not stable and in fact oftentimes you won’t have a perfect match. Also the Moon is actually on an orbit that will take it farther and farther away from the Earth, until one day (many Millions of years from now), it will only be a speck on the Sun when it passes in front of it.
It just so happens that we live in a time where the Moon just has the right distance *most of the time* to fit the visible diameter of the Sun. There is no law of nature that this *has* to be the case. Consider yourself lucky that you can experience this.
Luck. At this point in time as it slowly distances itself from earth it is pretty good for eclipses. When it was closer, it would have been even better though.
Probably the actual phrasing of your question should be: “How did I end up being born at just the right time in Earth’s history to witness total solar eclipses?”
It didn’t, exactly. That’s why we had an annular eclipse recently. It’s a solar eclipse when the moon is too far away (because its orbit is not a circle) to fully cover the solar disc.
The moon didn’t. The total eclipses exist because the moon is where it is, not the other way around. If the moon was orbiting 12 feet off the earths surface, you wouldn’t ask “how is the moon perfectly placed to just miss my basketball goal everyday?”
I like to imagine that Earth could be a major tourist destination for aliens looking to experience that perfect solar eclipse from the surface of a planet. This is despite the fact that they could just go put their spaceship in the right spot in space at any time to see the same effect. Maybe they want to see it from the novel location of an actual planet surface. Assuming they like our environment.
It didn’t.. you just happen to be born when the moon fully covers the Sun.. wait a few thousand years and it wont or a few thousand years ago and the moon was to small. Its slowly moving away from us making the days and nights longer.
It’s a coincidence that has to do with geometry. The portion of the sky taken up by an object is directly proportional to its radius and inversely proportional to its distance from the point of view. That is to say, if an object’s radius is doubled and its distance from the Earth is also doubled, it will appear just as big when seen from the Earth. As luck would have it, the sun is both roughly 500 times more far away from the Earth than the moon and has a radius roughly 500 times that of the moon, so the two celestial bodies take up very similar portions of the sky (ie. they appear approximatively the same size from the Earth)
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