Our Mysterious Moon

Even to astronomers, it's a perplexing puzzle

Listen to these intriguing podcast episodes from my colleague K-Town of Mysterious Radio

Have you ever wondered why our Moon and the Sun are (very nearly) the same apparent size in the sky?

There is no reason in astronomy or in astrophysics why this should be so. The coincidence of this “perfect fit” is statistically extremely unlikely.

Isaac Asimov called it the sheerest of coincidences:

The oddity of the Moon’s convenient diameter - and the solar eclipse peculiarly - and highly coincidentally the Moon’s diameter - combined with its distance from Earth allows our sister world to perfectly blot out the Sun during a solar eclipse. This is just another one of those oddities, it seems, because no other planet in our solar system has a moon that will do this anywhere nearly so perfectly, and there are hundreds of such moons. There is no astronomical reason why the Sun and the Moon should fit so well. It is the sheerest of coincidences, and only the Earth among all the planets is blessed in this fashion.

Until I listened to these podcasts, I’d had no idea this question has been such an active subject of debate among scientists.