<p>As the front image on the <a href="https://en.wikipedia.org/wiki/Solar_eclipse" rel="nofollow">wikipedia-page</a> already indicates, a total solar eclipse is not always total.
Earth's orbit is slightly elliptic, and so is the Moons orbit around the Earth.
Now take the Moon's slight orbital inclination into account and far from all total eclipses are really total.<br>
Unlike stated usually.
In fact wiki states "On average, the Moon appears to be slightly smaller than the Sun as seen from the Earth, so the majority (about 60%) of central eclipses are annular."</p>

<p>On a sidenote: It's important to understand that if the inclination and eccentricity of the orbit would be zero, then we'd have a perfect total solar eclipse on earth every month!
But yeah you can look it up, that this is not the case. There are, after all, not every month news reports from ppl staring into the sun, are there ;)</p>

<p>On other note, we know that the Moon is increasing its distance to earth. This happens because Orbital angular momentum is converted into internal heat for both bodies through <a href="https://en.wikipedia.org/wiki/Tidal_force" rel="nofollow">tidal forces</a>.<br>
This situation will evolve over time, so yes, it's a coincidence.</p>

<p>And no, I'm not aware of the Moon's distance having any strong implications for life.<br>
Tell me, if this is not clarified enough from the above.</p>

CC BY-SA 3.0
2015-07-02T20:59:40.210Z
You said: "This happens because Orbital angular momentum is converted into internal heat for both bodies" it's wrong because it causes to decreasing of distance between Moon and Earth! See BillOre answer.
Ab_Sh
CC BY-SA 3.0
2015-07-02T22:34:19.390Z
@2000, as the Moon causes the Earth's tidal bulge, it also causes heating in the Earth.  The bulge and tidal torque is what primarily causes the Moon to speed up and recede from the Earth, but the heat generated by this process has to be lost or absorbed somewhere.
BillDOe
CC BY-SA 3.0
2015-07-02T17:26:54.383Z
2015-07-02T17:26:54.383Z
AtmosphericPrisonEscape
<p>That the Moon and Sun both have about the same angular size is just a coincidence; we (humans) just happen to be around at a time when this is so. Tidal torque is causing the Moon to speed up (which in turn is causing the Earth to slow down and the Moon's distance to increase as it gains orbital velocity), so eventually the Moon's angular size will always be less than the Sun's. Then no eclipses will be total, with the Moon only covering up a portion of the Sun's disk.<br><br>The Moon raises tides on the earth, but Earth's more rapid rotation than the Moon's orbit causes the Earth to pull the tidal bulge ahead of the Moon.<br><br>There are some hypothesis that life may have begun in tidal pools where the Sun's ultraviolet radiation may have been the energy that caused the chemical reactions that created the precursors to life. Because the Moon was so much closer billions of years ago, the tides would have been much larger than today, so tidal pools would have been undisturbed for weeks at a time. This is, in my opinion, hypothesis, not theory, though it certainly seems plausible.</p>

CC BY-SA 3.0
2015-07-02T19:39:58.193Z
2015-07-02T22:29:17.390Z
2015-07-02T22:29:17.390Z
BillDOe
<p>We know that the visual size of the Sun and Moon from the Earth in our lifetime (!) is nearly equivalent.<br>
Now my question: Is this event is random? Or have a scientific reason?<br>
For example, maybe there is a connection between this and the formation of life on the Earth...</p>

CC BY-SA 3.0
2015-07-02T13:19:55.527Z
I don't know if the apparent size of the Sun and the Moon have anything to do with this, but [this study](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3053514/) claimed to have found that total solar eclipses have a positive effect on the microbes studied.
called2voyage
CC BY-SA 3.0
2015-07-02T14:14:14.987Z
@called2voyage:Thanks.  By [Giant impact hypothesis](https://en.wikipedia.org/wiki/Giant_impact_hypothesis) we observe that the density of Moon is about the density of Earth mantel(See [here](https://en.wikipedia.org/wiki/File:RadialDensityPREM.jpg)) and by according to the effect of tide on formation of life in [this article](http://www.scientificamerican.com/article/moon-life-tides/) i guess one can find some relations between distance of Moon from Earth and the radius of Moon...
Ab_Sh
<the-moon><the-sun><life><formation><origin-of-life>
Accidental or deliberate?
Ab_Sh
# Accidental or deliberate?

(Asked by: username_0 on 2015-07-02)

We know that the visual size of the Sun and Moon from the Earth in our lifetime (!) is nearly equivalent.  
Now my question: Is this event is random? Or have a scientific reason?  
For example, maybe there is a connection between this and the formation of life on the Earth...

**Tags:** the-moon, the-sun, life, formation, origin-of-life
> **Comments:**
> **username_1**: I don't know if the apparent size of the Sun and the Moon have anything to do with this, but [this study](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3053514/) claimed to have found that total solar eclipses have a positive effect on the microbes studied.  
> **username_0**: @called2voyage:Thanks.  By [Giant impact hypothesis](https://en.wikipedia.org/wiki/Giant_impact_hypothesis) we observe that the density of Moon is about the density of Earth mantel(See [here](https://en.wikipedia.org/wiki/File:RadialDensityPREM.jpg)) and by according to the effect of tide on formation of life in [this article](http://www.scientificamerican.com/article/moon-life-tides/) i guess one can find some relations between distance of Moon from Earth and the radius of Moon...  

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## 2 answers

### Answer by username_2 on 2015-07-02. Score: 1

As the front image on the [wikipedia-page](https://en.wikipedia.org/wiki/Solar_eclipse) already indicates, a total solar eclipse is not always total.
Earth's orbit is slightly elliptic, and so is the Moons orbit around the Earth.
Now take the Moon's slight orbital inclination into account and far from all total eclipses are really total.  
Unlike stated usually.
In fact wiki states "On average, the Moon appears to be slightly smaller than the Sun as seen from the Earth, so the majority (about 60%) of central eclipses are annular."

On a sidenote: It's important to understand that if the inclination and eccentricity of the orbit would be zero, then we'd have a perfect total solar eclipse on earth every month!
But yeah you can look it up, that this is not the case. There are, after all, not every month news reports from ppl staring into the sun, are there ;)

On other note, we know that the Moon is increasing its distance to earth. This happens because Orbital angular momentum is converted into internal heat for both bodies through [tidal forces](https://en.wikipedia.org/wiki/Tidal_force).  
This situation will evolve over time, so yes, it's a coincidence.

And no, I'm not aware of the Moon's distance having any strong implications for life.  
Tell me, if this is not clarified enough from the above.

> **Comments:**
> **username_0**: You said: "This happens because Orbital angular momentum is converted into internal heat for both bodies" it's wrong because it causes to decreasing of distance between Moon and Earth! See BillOre answer.  
> **username_3**: @2000, as the Moon causes the Earth's tidal bulge, it also causes heating in the Earth.  The bulge and tidal torque is what primarily causes the Moon to speed up and recede from the Earth, but the heat generated by this process has to be lost or absorbed somewhere.  

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### Answer by username_3 on 2015-07-02. Score: 1

That the Moon and Sun both have about the same angular size is just a coincidence; we (humans) just happen to be around at a time when this is so. Tidal torque is causing the Moon to speed up (which in turn is causing the Earth to slow down and the Moon's distance to increase as it gains orbital velocity), so eventually the Moon's angular size will always be less than the Sun's. Then no eclipses will be total, with the Moon only covering up a portion of the Sun's disk.  
  
The Moon raises tides on the earth, but Earth's more rapid rotation than the Moon's orbit causes the Earth to pull the tidal bulge ahead of the Moon.  
  
There are some hypothesis that life may have begun in tidal pools where the Sun's ultraviolet radiation may have been the energy that caused the chemical reactions that created the precursors to life. Because the Moon was so much closer billions of years ago, the tides would have been much larger than today, so tidal pools would have been undisturbed for weeks at a time. This is, in my opinion, hypothesis, not theory, though it certainly seems plausible.


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