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by atonse 806 days ago
Yes it’s an absolutely crazy coincidence that the moon is the correct proportion to its distance that results in perfect total eclipses.

I remember learning this fact in an astronomy class and that we’re not aware of this happening anywhere else in our solar system.

2 comments

Part of that is that Earth's moon is quite large compared to other moons like Phobos.

Here's a nice pic of Phobos and Deimos as seen from the mast-camera of Curiosity, compared with Luna.

I remember reading an Asimov piece many years ago where he was (typically) spinning out a kind of what-if about how the large size of the moon, and the consequent majorly-obvious eclipses, influenced the importance of ancient astronomy. Not to mention other effects like tides and moonlight.

He uses the "planet with a giant satellite" description of Earth as a plot point in Foundation (I think the final novel).
Nice, I’d love to read that.
It's also "temporary" (moon's orbital radius increases ~4cm/year)
Interesting! I wonder how long ago (if ever) eclipses weren't even possible
it's the opposite, a long time ago eclipses were "bigger" and happened more often, as the moon drifts farther away, it seems smaller to us and will no longer be big enough in our sky to block the sun one day.
Then we will have to endure a few million years of people arguing whether or not it should be called an eclipse or a transit
Thanks for clarifying
Estimates suggest that total solar eclipses could cease to occur in about 600 million years from now, give or take, depending on the precise nature of lunar recession and changes in Earth's rotation. This timeframe is long enough that many other changes on Earth and in the solar system will also occur, making the cessation of total solar eclipses just one of many transformations.