<p>It has <a href="https://en.wikipedia.org/wiki/Orbit_of_the_Moon#Tidal_evolution" rel="nofollow noreferrer">increased in radius</a> since the formation of the Earth-Moon system. There were eclipses since then. See <a href="https://en.wikipedia.org/wiki/Eclipse#Earth%E2%80%93Moon_system" rel="nofollow noreferrer">Eclipse</a>.
<a href="https://i.sstatic.net/jNpj1.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/jNpj1.gif" alt="enter image description here"></a>
<a href="http://hyperphysics.phy-astr.gsu.edu/hbase/Solar/lunecl.html" rel="nofollow noreferrer">Hyperphysics</a>  </p>

<p>The only way you would <strong>not</strong> have (at least partial) eclipses is if the Moon's rotation were exactly synchronized so it never passed through the ecliptic plane near the favourable time.</p>

CC BY-SA 4.0
2020-04-05T08:38:59.493Z
In the link you provided for eclipse there is no information about the past billions of years but only last 3000 years.
sidharth chhabra
CC BY-SA 4.0
2020-04-05T14:54:29.833Z
@sidharthchhabra That just explains the geometry of how eclipses happen. You will always get eclipses (at least partial) unless the year is miraculously some exact rational-number multiple  of the month.
Keith McClary
CC BY-SA 4.0
2020-04-05T16:37:23.127Z
What is the evidence that there will certainly be eclipses? Can you please share some details behind your answer. If the inclination of the moon's orbit is more than say 30 degrees, would there still be eclipses?
sidharth chhabra
CC BY-SA 4.0
2020-04-05T18:00:33.900Z
Thank you Keith for putting in some more diagrams and information. In the illustration, moon's orbit has 5 degree tilt w.r.t ecliptic plane in left direction. Is it possible that moon's orbit was tilted at x degrees w.r.t ecliptic plane but in the direction of the Sun? In such a case, there won't be any eclipses.
sidharth chhabra
CC BY-SA 4.0
2020-04-05T20:52:42.527Z
@sidharthchhabra No, the axis of the Moon's orbit points in the same direction (i.e. towards some distant star) throughout the year. If it was pointing a different direction, the "favourable" time might be a different month of the year.
Keith McClary
CC BY-SA 4.0
2020-04-05T23:25:40.243Z
@Keith Actually, the Moon's orbital plane precesses rather quickly, with a period of about 18.6 years, see https://en.wikipedia.org/wiki/Lunar_precession which also discusses the lunar apsidal and axial precession. But of course the lunar nodal precession does not undermine your argument about eclipses.
PM 2Ring
CC BY-SA 4.0
2020-04-05T03:38:33.480Z
2020-04-05T17:34:28.170Z
2020-04-05T17:34:28.170Z
Keith McClary
<p>The distance between the Earth and the Moon increases by roughly 4 cm per year. So when it formed, it was much closer to Earth than it is now. This means that its angular diameter, as seen from Earth, used to be larger than that of the Sun. In the future, as the Moon keeps getting further away, its angular diameter will become smaller than that of the Sun, so during eclipses, the Sun will likely no longer be completely obscured. </p>

CC BY-SA 4.0
2020-04-05T23:28:12.167Z
FWIW, it will take about 600 million years before the Moon will be too distant to cause total solar eclipses.
PM 2Ring
CC BY-SA 4.0
2020-04-05T13:59:51.540Z
2020-04-05T13:59:51.540Z
usernumber
<p>The wasn't originally in our solar system, so when it came here it came into earth's orbit it's orbit was large and lopsided. Over time it got into a more even orbit.</p>

CC BY-SA 4.0
2020-11-16T04:03:03.267Z
I assume you meant to say "The Moon wasn't originally in our solar system". Do you have any evidence for that rather unlikely claim?
PM 2Ring
CC BY-SA 4.0
2020-11-16T04:04:13.997Z
Can you add more details?
WarpPrime
CC BY-SA 4.0
2020-11-15T23:32:20.360Z
2020-11-15T23:32:20.360Z
Scot Mason
<p>Has our moon’s orbit shifted since its formation? Has there been eclipses on the Earth since last ~4 billion years? In other words, was there a time when Moon's orbit was at an inclination to Earth's orbit around the Sun that there were no eclipses? How would you find out such a phenomenon? Are there any paleontological or geological or astronomical data points which can provide insight here?</p>
<p><a href="https://i.sstatic.net/JuS5X.gif" rel="nofollow noreferrer"><img src="https://i.sstatic.net/JuS5X.gif" alt="Moon's rotation around the Earth creating eclipses" /></a></p>
<p>In the illustration, moon's orbit has 5 degree tilt w.r.t ecliptic plane in left direction. Is it possible that moon's orbit was tilted at x degrees w.r.t ecliptic plane but in the direction of the Sun? In such a case, there won't be any eclipses!</p>
<p>ps: thanks keith for the illustration</p>

CC BY-SA 4.0
2020-04-05T04:35:08.860Z
The moon did not exist from the beginning of the solar system. The moon was formed ~4.5 billion years ago, about 30–50 million years after the origin of the Solar System-https://sservi.nasa.gov/articles/nasa-scientist-jen-heldmann-describes-how-the-earths-moon-was-formed/
Bob516
CC BY-SA 4.0
2020-04-05T08:35:37.930Z
That’s important detail but inconsequential here.
sidharth chhabra
CC BY-SA 4.0
2020-04-05T13:21:25.493Z
I agree it does not answer the question, but it offers a better understanding of the history.  That is why I left it as a comment and not an answer.
Bob516
CC BY-SA 4.0
2020-04-05T13:33:06.587Z
When you say shifted do you mean the its angle of inclination or its distance from the earth?  Asking about an eclipse are you imagining the same scenario as today where the sun and the moon have the same angular diameter and during a total eclipse the dramatic view of the corona is possible?  When the moon was first formed it orbited much closer to the earth than it does now, so its angular diameter was substantially bigger than it is today. There would've been no dramatic views of the corona at that time, or for most of the history of the moon.
Bob516
CC BY-SA 4.0
2020-04-05T13:56:05.387Z
I tried to rephrase the question to get to what I think you're asking about. Do rollback my edit if I misinterpreted your intent.
usernumber
CC BY-SA 4.0
2020-04-05T15:06:23.797Z
Yes, I rollback your edit. I have added more words to make my intent clear. Please let me know if you feel it need more explanation.
sidharth chhabra
CC BY-SA 4.0
2020-04-05T15:14:54.393Z
As I commented below, even if the Moon's orbit is inclined (as it is), there will be randomly be times when the Moon crosses the ecliptic plane when it is between the Earth and Sun. If the orbit was not inclined we would get an eclipse every month!
Keith McClary
CC BY-SA 4.0
2020-04-05T15:15:09.720Z
@sidharthchhabra Why do you insist on wording the question with the phrase "since the beginning of the solar system" when that is inconsistent with the facts?
Bob516
CC BY-SA 4.0
2020-04-05T16:33:43.023Z
@Bob516 you are right. I fixed that.
sidharth chhabra
CC BY-SA 4.0
2020-11-15T04:54:00.910Z
Yes (Earlier, day length on Earth was about 6 hrs long): https://astronomy.stackexchange.com/questions/26253/how-fast-was-the-earth-spinning-directly-after-the-moon-formed
Nilay Ghosh
<the-moon><earth><solar-eclipse><lunar-eclipse>
Moon’s orbit shift
sidharth chhabra
# Moon’s orbit shift

(Asked by: username_0 on 2020-04-05)

Has our moon’s orbit shifted since its formation? Has there been eclipses on the Earth since last ~4 billion years? In other words, was there a time when Moon's orbit was at an inclination to Earth's orbit around the Sun that there were no eclipses? How would you find out such a phenomenon? Are there any paleontological or geological or astronomical data points which can provide insight here?

[![Moon's rotation around the Earth creating eclipses](https://i.sstatic.net/JuS5X.gif)](https://i.sstatic.net/JuS5X.gif)

In the illustration, moon's orbit has 5 degree tilt w.r.t ecliptic plane in left direction. Is it possible that moon's orbit was tilted at x degrees w.r.t ecliptic plane but in the direction of the Sun? In such a case, there won't be any eclipses!

ps: thanks keith for the illustration

**Tags:** the-moon, earth, solar-eclipse, lunar-eclipse
> **Comments:**
> **username_1**: The moon did not exist from the beginning of the solar system. The moon was formed ~4.5 billion years ago, about 30–50 million years after the origin of the Solar System-https://sservi.nasa.gov/articles/nasa-scientist-jen-heldmann-describes-how-the-earths-moon-was-formed/  
> **username_0**: That’s important detail but inconsequential here.  
> **username_1**: I agree it does not answer the question, but it offers a better understanding of the history.  That is why I left it as a comment and not an answer.  
> **username_1**: When you say shifted do you mean the its angle of inclination or its distance from the earth?  Asking about an eclipse are you imagining the same scenario as today where the sun and the moon have the same angular diameter and during a total eclipse the dramatic view of the corona is possible?  When the moon was first formed it orbited much closer to the earth than it does now, so its angular diameter was substantially bigger than it is today. There would've been no dramatic views of the corona at that time, or for most of the history of the moon.  
> **username_2**: I tried to rephrase the question to get to what I think you're asking about. Do rollback my edit if I misinterpreted your intent.  
> **username_0**: Yes, I rollback your edit. I have added more words to make my intent clear. Please let me know if you feel it need more explanation.  
> **username_3**: As I commented below, even if the Moon's orbit is inclined (as it is), there will be randomly be times when the Moon crosses the ecliptic plane when it is between the Earth and Sun. If the orbit was not inclined we would get an eclipse every month!  
> **username_1**: @sidharthchhabra Why do you insist on wording the question with the phrase "since the beginning of the solar system" when that is inconsistent with the facts?  
> **username_0**: @Bob516 you are right. I fixed that.  
> **username_4**: Yes (Earlier, day length on Earth was about 6 hrs long): https://astronomy.stackexchange.com/questions/26253/how-fast-was-the-earth-spinning-directly-after-the-moon-formed  

---

## 3 answers

### Answer by username_3 on 2020-04-05. Score: 4

It has [increased in radius](https://en.wikipedia.org/wiki/Orbit_of_the_Moon#Tidal_evolution) since the formation of the Earth-Moon system. There were eclipses since then. See [Eclipse](https://en.wikipedia.org/wiki/Eclipse#Earth%E2%80%93Moon_system).
[![enter image description here](https://i.sstatic.net/jNpj1.gif)](https://i.sstatic.net/jNpj1.gif)
[Hyperphysics](http://hyperphysics.phy-astr.gsu.edu/hbase/Solar/lunecl.html)

The only way you would **not** have (at least partial) eclipses is if the Moon's rotation were exactly synchronized so it never passed through the ecliptic plane near the favourable time.

> **Comments:**
> **username_0**: In the link you provided for eclipse there is no information about the past billions of years but only last 3000 years.  
> **username_3**: @sidharthchhabra That just explains the geometry of how eclipses happen. You will always get eclipses (at least partial) unless the year is miraculously some exact rational-number multiple  of the month.  
> **username_0**: What is the evidence that there will certainly be eclipses? Can you please share some details behind your answer. If the inclination of the moon's orbit is more than say 30 degrees, would there still be eclipses?  
> **username_0**: Thank you Keith for putting in some more diagrams and information. In the illustration, moon's orbit has 5 degree tilt w.r.t ecliptic plane in left direction. Is it possible that moon's orbit was tilted at x degrees w.r.t ecliptic plane but in the direction of the Sun? In such a case, there won't be any eclipses.  
> **username_3**: @sidharthchhabra No, the axis of the Moon's orbit points in the same direction (i.e. towards some distant star) throughout the year. If it was pointing a different direction, the "favourable" time might be a different month of the year.  
> **username_5**: @Keith Actually, the Moon's orbital plane precesses rather quickly, with a period of about 18.6 years, see https://en.wikipedia.org/wiki/Lunar_precession which also discusses the lunar apsidal and axial precession. But of course the lunar nodal precession does not undermine your argument about eclipses.  

---

### Answer by username_2 on 2020-04-05. Score: 2

The distance between the Earth and the Moon increases by roughly 4 cm per year. So when it formed, it was much closer to Earth than it is now. This means that its angular diameter, as seen from Earth, used to be larger than that of the Sun. In the future, as the Moon keeps getting further away, its angular diameter will become smaller than that of the Sun, so during eclipses, the Sun will likely no longer be completely obscured.

> **Comments:**
> **username_5**: FWIW, it will take about 600 million years before the Moon will be too distant to cause total solar eclipses.  

---

### Answer by username_6 on 2020-11-15. Score: -1

The wasn't originally in our solar system, so when it came here it came into earth's orbit it's orbit was large and lopsided. Over time it got into a more even orbit.

> **Comments:**
> **username_5**: I assume you meant to say "The Moon wasn't originally in our solar system". Do you have any evidence for that rather unlikely claim?  
> **username_7**: Can you add more details?  

---

