<p>Depending on the assumptions you make, the Moon would suddenly have a retrograde orbit. If the moon had a retrograde orbit, it would have tremendous consequences. Retrograde orbits tend to become less distant over time, meaning the moon would either be much closer to the Earth with huge tidal effects or come more close in the future. At some point, the Moon would or would have passed the Earth's <a href="http://en.wikipedia.org/wiki/Roche_limit">Roche limit</a>, break up, and create a temporary ring system which would shower the Earth with impacts.</p>

CC BY-SA 3.0
2014-05-01T14:41:36.093Z
Why do retrograde orbits become less distant?  Tidal effects?
gerrit
CC BY-SA 3.0
2014-05-01T14:46:46.603Z
Yes. See http://en.wikipedia.org/wiki/Orbital_decay#Tidal_effects
DCKing
CC BY-SA 3.0
2014-05-04T11:45:50.793Z
Oh, very good point! Even ignoring the dumping-the-moon-on-our-heads aspect (which would take a long time, I suspect), if one were to reverse the earth's rotation without changing the direction of the moon's orbit then that would change the length of the lunar day, and plenty of other periods that are important for tidal mechanics; so in addition to the earth's tides being very different due to reverse Coriolis, they'd be even more different thanks to altered periods, and thus different resonances.
Semidiurnal Simon
CC BY-SA 3.0
2015-04-02T23:56:37.903Z
Many species use the moon for timing and might have trouble adapting their phenology, too.
cphlewis
CC BY-SA 3.0
2014-05-01T14:14:22.037Z
2014-05-04T10:55:52.020Z
2014-05-04T10:55:52.020Z
DCKing
<p>That would have many consequences. For example the <a href="http://glossary.ametsoc.org/wiki/Coriolis_force">Coriolis force</a> would change the sign. Thus wind around pressure systems would switch the direction from north and south hemisphere, but also the <a href="http://en.wikipedia.org/wiki/Ekman_spiral">Ekman spiral</a> in the ocean would be affected. Surface heating at sloped terrain will different, as the sun would rise in the West. This would change thermal induced circulations. And the conservation of angular momentum is important for the general circulation.</p>

<p>I would expect major impacts on the resulting climate, even in an equilibrium mode, which does not account for the acceleration to the oppose rotation velocity.</p>

<p>During the time of stopped rotation additional circulation systems can be expected, which exchange energy between the day and the night side of the earth.</p>

CC BY-SA 3.0
2014-05-01T21:14:56.290Z
Ah, very interesting! Thank you for your answer.
Ruddy
CC BY-SA 3.0
2014-05-02T02:47:28.923Z
I would be most interested to see the transition in the atmosphere before things equlibrate to the change.  I've seen what happens in rotating tank experiments where you just stop the rotation, but to reverse must be even more interesting (and terrible).
casey
CC BY-SA 3.0
2014-05-04T11:42:15.410Z
@casey I would be very interested to this transition, but *from a distance*. If you decide to try this out, please use a spare planet rather than this one ;-)
Semidiurnal Simon
CC BY-SA 3.0
2014-05-05T03:11:44.243Z
There would be a bunch of other knock-on effects from switching the wind direction - for instance, there is a pattern of desertification on the western side of continents at mid latitudes. Presumably that would switch to the Eastern side.
naught101
CC BY-SA 3.0
2014-10-06T17:10:42.143Z
@BHF Should that be maJor impacts?
Michael Mior
CC BY-SA 4.0
2018-08-06T05:51:50.920Z
the slosh will be amazing, like watching from a different planet amazing.
John
CC BY-SA 3.0
2014-05-01T10:26:55.063Z
2014-10-06T17:21:28.570Z
2014-10-06T17:21:28.570Z
BHF
<p>Right, I saw a question about why the Earth spins counter clockwise, and it reminded me of something I would like to know the answer to. </p>

<p>I watched a episode of Futurama. In this episode the Earth stops spinning and they restart the Earth's spin, but going the other way (clockwise). </p>

<p>Would the Earth function in the same way if this was possible to do? What effects could this have?</p>

<p><strong>Note:</strong> I'm not even 100% what way we are spinning - it depends how you look at it, right? </p>

CC BY-SA 3.0
2014-05-01T13:27:12.703Z
Ah yes, _That Darn Katz!_. BTW, the convention is that Earth spins **counter** clockwise (looking down on the North Pole). As mentioned by others, wind directions would change, with local climatic differences, but otherwise life would go on.
Phil Perry
CC BY-SA 3.0
2014-09-23T19:21:17.527Z
Here is an (open access) article where they ran that planet in a climate model. V. Kamphuis, S. E. Huisman, and H. A. Dijkstra: The global ocean circulation on a retrograde rotating earth, http://dx.doi.org/10.5194/cp-7-487-2011
flo
<climate><planetary-science><hypothetical><earth-rotation>
Would the Earth function the same spinning the other way?
Ruddy
# Would the Earth function the same spinning the other way?

(Asked by: username_0 on 2014-05-01)

Right, I saw a question about why the Earth spins counter clockwise, and it reminded me of something I would like to know the answer to.

I watched a episode of Futurama. In this episode the Earth stops spinning and they restart the Earth's spin, but going the other way (clockwise).

Would the Earth function in the same way if this was possible to do? What effects could this have?

**Note:** I'm not even 100% what way we are spinning - it depends how you look at it, right?

**Tags:** climate, planetary-science, hypothetical, earth-rotation

> **Comments:**
> **username_1**: Ah yes, _That Darn Katz!_. BTW, the convention is that Earth spins **counter** clockwise (looking down on the North Pole). As mentioned by others, wind directions would change, with local climatic differences, but otherwise life would go on.  
> **username_2**: Here is an (open access) article where they ran that planet in a climate model. V. Kamphuis, S. E. Huisman, and H. A. Dijkstra: The global ocean circulation on a retrograde rotating earth, http://dx.doi.org/10.5194/cp-7-487-2011  

---

## 2 answers

### Answer by username_7 on 2014-05-01. Score: 28 | Accepted answer

That would have many consequences. For example the [Coriolis force](http://glossary.ametsoc.org/wiki/Coriolis_force) would change the sign. Thus wind around pressure systems would switch the direction from north and south hemisphere, but also the [Ekman spiral](http://en.wikipedia.org/wiki/Ekman_spiral) in the ocean would be affected. Surface heating at sloped terrain will different, as the sun would rise in the West. This would change thermal induced circulations. And the conservation of angular momentum is important for the general circulation.

I would expect major impacts on the resulting climate, even in an equilibrium mode, which does not account for the acceleration to the oppose rotation velocity.

During the time of stopped rotation additional circulation systems can be expected, which exchange energy between the day and the night side of the earth.

> **Comments:**
> **username_0**: Ah, very interesting! Thank you for your answer.  
> **username_8**: I would be most interested to see the transition in the atmosphere before things equlibrate to the change.  I've seen what happens in rotating tank experiments where you just stop the rotation, but to reverse must be even more interesting (and terrible).  
> **username_5**: @username_8 I would be very interested to this transition, but *from a distance*. If you decide to try this out, please use a spare planet rather than this one ;-)  
> **username_9**: There would be a bunch of other knock-on effects from switching the wind direction - for instance, there is a pattern of desertification on the western side of continents at mid latitudes. Presumably that would switch to the Eastern side.  
> **username_10**: @username_7 Should that be maJor impacts?  
> **username_11**: the slosh will be amazing, like watching from a different planet amazing.  

---

### Answer by username_3 on 2014-05-01. Score: 23

Depending on the assumptions you make, the Moon would suddenly have a retrograde orbit. If the moon had a retrograde orbit, it would have tremendous consequences. Retrograde orbits tend to become less distant over time, meaning the moon would either be much closer to the Earth with huge tidal effects or come more close in the future. At some point, the Moon would or would have passed the Earth's [Roche limit](http://en.wikipedia.org/wiki/Roche_limit), break up, and create a temporary ring system which would shower the Earth with impacts.

> **Comments:**
> **username_4**: Why do retrograde orbits become less distant?  Tidal effects?  
> **username_3**: Yes. See http://en.wikipedia.org/wiki/Orbital_decay#Tidal_effects  
> **username_5**: Oh, very good point! Even ignoring the dumping-the-moon-on-our-heads aspect (which would take a long time, I suspect), if one were to reverse the earth's rotation without changing the direction of the moon's orbit then that would change the length of the lunar day, and plenty of other periods that are important for tidal mechanics; so in addition to the earth's tides being very different due to reverse Coriolis, they'd be even more different thanks to altered periods, and thus different resonances.  
> **username_6**: Many species use the moon for timing and might have trouble adapting their phenology, too.  

---

