<p>Total solar eclipses are possible because the Moon is about 400 times smaller than the Sun and also 400 times closer than it is. In any planetary system, the odds of this should be near zero. Is there any literature on why it might be that these perfect conditions which should be a near zero probability event occur in our system?</p>
<p>One possible explanation could be that life somehow requires this (allowing us to invoke survivorship bias).</p>

CC BY-SA 4.0
2023-08-05T20:42:48.250Z
There's probably no way to answer this. We don't have any idea how common "large" moons around terrestrial plants are. Of the four terrestrial planets, only one has a large moon.  But is our solar system typical? Nobody knows.  On the other hand consider all the other things that could be equal:  the area of the sea could be equal to the area of the land.  The nearest two gas giants could have the equal masses. The temperature could be such that equal areas are ice covered.  The highest mountain could equal the greatest depth....etc etc etc.  None of these potential coincidences occur.
James K
CC BY-SA 4.0
2023-08-05T20:53:36.307Z
From Space.com's 2011 [Earth's Stabilizing Moon May Be Unique Within Universe](https://www.space.com/12464-earth-moon-unique-solar-system-universe.html) "The moon has long been recognized as a significant stabilizer of Earth's orbital axis. Without it, astronomers have predicted that Earth's tilt could vary as much as 85 degrees. In such a scenario, the sun would swing from being directly over the equator to directly over the poles over the course of a few million years, a change which could result in dramatic climatic shifts."
uhoh
CC BY-SA 4.0
2023-08-05T20:54:15.640Z
However also see Science's [Who Needs a Moon? Earth-like extrasolar planets could be suitable for life even if their rotation is not stabilized by a large moon](https://www.science.org/content/article/who-needs-moon)
uhoh
CC BY-SA 4.0
2023-08-05T22:36:03.773Z
However, while a large moon, and more stable rotation, may make it easier for life, there is little reason to believe the close 1:1 ratio in apparent size is in some way significant, after all this has only existed relatively recently (in geological time)
James K
<solar-eclipse><life>
Why are total solar eclipses possible (probability wise)
Rohit Pandey
# Why are total solar eclipses possible (probability wise)

(Asked by: username_0 on 2023-08-05)

Total solar eclipses are possible because the Moon is about 400 times smaller than the Sun and also 400 times closer than it is. In any planetary system, the odds of this should be near zero. Is there any literature on why it might be that these perfect conditions which should be a near zero probability event occur in our system?

One possible explanation could be that life somehow requires this (allowing us to invoke survivorship bias).

**Tags:** solar-eclipse, life
> **Comments:**
> **username_1**: There's probably no way to answer this. We don't have any idea how common "large" moons around terrestrial plants are. Of the four terrestrial planets, only one has a large moon.  But is our solar system typical? Nobody knows.  On the other hand consider all the other things that could be equal:  the area of the sea could be equal to the area of the land.  The nearest two gas giants could have the equal masses. The temperature could be such that equal areas are ice covered.  The highest mountain could equal the greatest depth....etc etc etc.  None of these potential coincidences occur.  
> **username_2**: From Space.com's 2011 [Earth's Stabilizing Moon May Be Unique Within Universe](https://www.space.com/12464-earth-moon-unique-solar-system-universe.html) "The moon has long been recognized as a significant stabilizer of Earth's orbital axis. Without it, astronomers have predicted that Earth's tilt could vary as much as 85 degrees. In such a scenario, the sun would swing from being directly over the equator to directly over the poles over the course of a few million years, a change which could result in dramatic climatic shifts."  
> **username_2**: However also see Science's [Who Needs a Moon? Earth-like extrasolar planets could be suitable for life even if their rotation is not stabilized by a large moon](https://www.science.org/content/article/who-needs-moon)  
> **username_1**: However, while a large moon, and more stable rotation, may make it easier for life, there is little reason to believe the close 1:1 ratio in apparent size is in some way significant, after all this has only existed relatively recently (in geological time)  

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