<p>Actual diagrams, rather than made-up artists' impressions, can be found at NASA JPL. <a href="https://ssd.jpl.nasa.gov/?orbits" rel="nofollow noreferrer">https://ssd.jpl.nasa.gov/?orbits</a></p>

<p>The ellipticity of planetary orbits are in general quite small and they are <strong>not</strong> aligned. <a href="http://www.met.rdg.ac.uk/~ross/Astronomy/Planets.html" rel="nofollow noreferrer">http://www.met.rdg.ac.uk/~ross/Astronomy/Planets.html</a> gives a table of orbital elements in the solar system. The longitudes of perihelion (labelled as "<span class="math-container">$\sim \omega$</span>") are different - indicating that the "eccentricity vectors" (as you put it, and keep asking for) are pointing in essentially random directions around the ecliptic plane.</p>

<p>Many of the diagrams that you see are drawn from perspectives that are not looking straight down on the ecliptic plane. If that is the case then of course you see (highly) elliptical shapes (even when the orbits are nearly circular)  that appear aligned. That is merely a perspective effect.</p>

CC BY-SA 4.0
2019-12-14T14:02:17.573Z
If they are not aligned then the idea was wrong. This image, from the link you posted, does show that they look pretty aligned. https://imgur.com/a/Wpbokcu. Is it using wrong data (as it might be focusing more on accuracy for objects further out?). antispinwards comments also mentioned "fairly aligned".
Kornelia
CC BY-SA 4.0
2019-12-14T14:49:37.490Z
I think I see your misunderstanding!  That image shows a view of the solar system from one side.  The ellipses that you see are **not** due to Keplerian orbits, but just due to (almost) circular orbits that are being viewed from the side.  **There is no alignment**, the planets are not **pretty aligned** Your posted image only shows a perspective effect.
James K
CC BY-SA 4.0
2019-12-14T15:01:16.890Z
aware of that yes. the elliptical orbits of planets is not a perspective effect though. the idea was simply based on if they were aligned. if they are not, would be good to have source for that.
Kornelia
CC BY-SA 4.0
2019-12-14T15:43:36.593Z
"This image, from the link you posted, does show that they look pretty aligned." @Kornelia Please read the explanatory caption to that image, which says it is an "oblique" view of the solar system.
ProfRob
CC BY-SA 4.0
2019-12-14T13:55:18.700Z
2019-12-14T15:51:21.417Z
2019-12-14T15:51:21.417Z
ProfRob
<p>First of all, to make <em>absolutely sure</em> we're on the same page about the shape of the elliptical orbits, seeing as there's been some confusion in the comments, I've included the same two pictures from <em>both top down and at an oblique angle</em>.</p>

<p><a href="https://i.sstatic.net/kgM1N.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/kgM1N.png" alt="enter image description here"></a> </p>

<h2>Which directions are the planets' orbital eccentricities pointing to?</h2>

<p>You can find out the longitudinal direction by adding the <a href="https://en.wikipedia.org/wiki/Longitude_of_the_ascending_node" rel="nofollow noreferrer">longitude of the ascending node</a> to the <a href="https://en.wikipedia.org/wiki/Argument_of_periapsis" rel="nofollow noreferrer">argument of perihelion</a>. This information is all in wikipedia but I've gone and processed it anyway. 
<a href="https://i.sstatic.net/iK9mD.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/iK9mD.png" alt="enter image description here"></a></p>

<p>Mercury is a bit of an anomaly because its orbit precesses over time and so the direction of its major axis changes very slowly (it takes 12 million orbits for the major axis to do a full 360 degree sweep). The other planets have their major axes scattered fairly evenly, by my eye.</p>

<h2>Which direction is the sun moving in?</h2>

<p>This was answered <a href="https://astronomy.stackexchange.com/questions/28584/in-which-direction-is-the-sun-travelling/28588#28588">here.</a> The Sun is moving through the galaxy in a direction 60 degrees from the ecliptic, which is not aligned with the eccentricities of any planets.</p>

CC BY-SA 4.0
2019-12-16T07:39:04.217Z
2019-12-16T07:39:04.217Z
Ingolifs
<p>The assumption is made that the planets of our solar system all have elliptical orbits elongated in the same direction. Further, generalized to that orbits around any object with its own orbital vector should have elliptical orbits, including moons orbiting planets.</p>

<p><a href="https://i.sstatic.net/dcEl3.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/dcEl3.png" alt="enter image description here"></a></p>

<p><a href="https://i.sstatic.net/6bUY8.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/6bUY8.png" alt="enter image description here"></a></p>

CC BY-SA 4.0
2019-12-14T13:11:45.430Z
Ok. If their ellipse vector is completely different then the idea would be wrong. Do you know any good source for where to see the different eccentricity vectors?
Kornelia
CC BY-SA 4.0
2019-12-14T13:12:53.110Z
In images they're often portrayed as aligned, http://www.pas.rochester.edu/~blackman/ast104/planet_orbits-inner-sideview.gif
Kornelia
CC BY-SA 4.0
2019-12-14T13:17:33.040Z
and, from my own reading here, it looks like they are pretty much aligned. If they are not, the idea is moot, but, seems corroborated by this post for example,
https://www.quora.com/What-does-a-diagram-of-the-actual-orbital-path-of-planets-in-the-solar-system-look-like
Kornelia
CC BY-SA 4.0
2019-12-14T13:21:13.337Z
OK. So, the planets are fairly aligned?
Kornelia
CC BY-SA 4.0
2019-12-14T13:25:28.363Z
But you said they were fairly aligned. They tend to be aligned in most images, and, just from simple reading. Do you happen to have a good source where I could educate myself in the exact eccentricity vectors, for example the source you base what you say on?
Kornelia
CC BY-SA 4.0
2019-12-14T13:26:06.370Z
and if that source is in some text book not accessible online, some other source
Kornelia
CC BY-SA 4.0
2019-12-14T13:43:26.563Z
Nope. The question was an honest question. If it is clearly wrong, then I'd take that in, just need to see the evidence. You brought up that the eccentricity vector was not aligned for the planets. You mentioned coplanar alignment as well, I have not. Coplanar is along different axis than what the question is about. Overall, I'm just interested in the evidence, it was, genuinely, an honest question from myself, and if it is clearly wrong then I'll adjust my beliefs.
Kornelia
CC BY-SA 4.0
2019-12-14T14:41:10.820Z
Yes largest eccentricity Pluto, 0.25, still small. It isn't that I misunderstand that. It seemed to me like if the sun itself was moving, that would affect the orbits of the planets. It'd be good to have accurate data for the eccentricity vectors, if you happen to have a good source, feel free to point to it.
Kornelia
CC BY-SA 4.0
2019-12-14T14:48:31.363Z
Yes, you said that in previous comment. The idea itself is disproven if the elliptical orbits (whether or not eccentricity is large) are not aligned in a similar direction. Would be good to have evidence of that, if there is a good source for it.
Kornelia
CC BY-SA 4.0
2019-12-14T14:49:56.050Z
here, eccentricity of them. https://www.coursehero.com/qa/attachment/3387485/ think of image as artist impression. overall, idea disproven if eccentricity vector is not aligned, or, to some extent aligned. would be good to have a source to see that.
Kornelia
<orbital-mechanics>
Do planets orbit the sun in ellipses because of sun movement vector?
Kornelia
# Do planets orbit the sun in ellipses because of sun movement vector?

(Asked by: username_0 on 2019-12-14)

The assumption is made that the planets of our solar system all have elliptical orbits elongated in the same direction. Further, generalized to that orbits around any object with its own orbital vector should have elliptical orbits, including moons orbiting planets.

[![enter image description here](https://i.sstatic.net/dcEl3.png)](https://i.sstatic.net/dcEl3.png)

[![enter image description here](https://i.sstatic.net/6bUY8.png)](https://i.sstatic.net/6bUY8.png)

**Tags:** orbital-mechanics
> **Comments:**
> **username_0**: Ok. If their ellipse vector is completely different then the idea would be wrong. Do you know any good source for where to see the different eccentricity vectors?  
> **username_0**: In images they're often portrayed as aligned, http://www.pas.rochester.edu/~blackman/ast104/planet_orbits-inner-sideview.gif  
> **username_0**: and, from my own reading here, it looks like they are pretty much aligned. If they are not, the idea is moot, but, seems corroborated by this post for example, https://www.quora.com/What-does-a-diagram-of-the-actual-orbital-path-of-planets-in-the-solar-system-look-like  
> **username_0**: OK. So, the planets are fairly aligned?  
> **username_0**: But you said they were fairly aligned. They tend to be aligned in most images, and, just from simple reading. Do you happen to have a good source where I could educate myself in the exact eccentricity vectors, for example the source you base what you say on?  
> **username_0**: and if that source is in some text book not accessible online, some other source  
> **username_0**: Nope. The question was an honest question. If it is clearly wrong, then I'd take that in, just need to see the evidence. You brought up that the eccentricity vector was not aligned for the planets. You mentioned coplanar alignment as well, I have not. Coplanar is along different axis than what the question is about. Overall, I'm just interested in the evidence, it was, genuinely, an honest question from myself, and if it is clearly wrong then I'll adjust my beliefs.  
> **username_0**: Yes largest eccentricity Pluto, 0.25, still small. It isn't that I misunderstand that. It seemed to me like if the sun itself was moving, that would affect the orbits of the planets. It'd be good to have accurate data for the eccentricity vectors, if you happen to have a good source, feel free to point to it.  
> **username_0**: Yes, you said that in previous comment. The idea itself is disproven if the elliptical orbits (whether or not eccentricity is large) are not aligned in a similar direction. Would be good to have evidence of that, if there is a good source for it.  
> **username_0**: here, eccentricity of them. https://www.coursehero.com/qa/attachment/3387485/ think of image as artist impression. overall, idea disproven if eccentricity vector is not aligned, or, to some extent aligned. would be good to have a source to see that.  

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## 2 answers

### Answer by username_1 on 2019-12-14. Score: 4

Actual diagrams, rather than made-up artists' impressions, can be found at NASA JPL. <https://ssd.jpl.nasa.gov/?orbits>

The ellipticity of planetary orbits are in general quite small and they are **not** aligned. <http://www.met.rdg.ac.uk/~ross/Astronomy/Planets.html> gives a table of orbital elements in the solar system. The longitudes of perihelion (labelled as "$\sim \omega$") are different - indicating that the "eccentricity vectors" (as you put it, and keep asking for) are pointing in essentially random directions around the ecliptic plane.

Many of the diagrams that you see are drawn from perspectives that are not looking straight down on the ecliptic plane. If that is the case then of course you see (highly) elliptical shapes (even when the orbits are nearly circular) that appear aligned. That is merely a perspective effect.

> **Comments:**
> **username_0**: If they are not aligned then the idea was wrong. This image, from the link you posted, does show that they look pretty aligned. https://imgur.com/a/Wpbokcu. Is it using wrong data (as it might be focusing more on accuracy for objects further out?). antispinwards comments also mentioned "fairly aligned".  
> **username_2**: I think I see your misunderstanding!  That image shows a view of the solar system from one side.  The ellipses that you see are **not** due to Keplerian orbits, but just due to (almost) circular orbits that are being viewed from the side.  **There is no alignment**, the planets are not **pretty aligned** Your posted image only shows a perspective effect.  
> **username_0**: aware of that yes. the elliptical orbits of planets is not a perspective effect though. the idea was simply based on if they were aligned. if they are not, would be good to have source for that.  
> **username_1**: "This image, from the link you posted, does show that they look pretty aligned." @Kornelia Please read the explanatory caption to that image, which says it is an "oblique" view of the solar system.  

---

### Answer by username_3 on 2019-12-16. Score: 3

First of all, to make *absolutely sure* we're on the same page about the shape of the elliptical orbits, seeing as there's been some confusion in the comments, I've included the same two pictures from *both top down and at an oblique angle*.

[![enter image description here](https://i.sstatic.net/kgM1N.png)](https://i.sstatic.net/kgM1N.png)

## Which directions are the planets' orbital eccentricities pointing to?

You can find out the longitudinal direction by adding the [longitude of the ascending node](https://en.wikipedia.org/wiki/Longitude_of_the_ascending_node) to the [argument of perihelion](https://en.wikipedia.org/wiki/Argument_of_periapsis). This information is all in wikipedia but I've gone and processed it anyway.
[![enter image description here](https://i.sstatic.net/iK9mD.png)](https://i.sstatic.net/iK9mD.png)

Mercury is a bit of an anomaly because its orbit precesses over time and so the direction of its major axis changes very slowly (it takes 12 million orbits for the major axis to do a full 360 degree sweep). The other planets have their major axes scattered fairly evenly, by my eye.

## Which direction is the sun moving in?

This was answered [here.](https://astronomy.stackexchange.com/questions/28584/in-which-direction-is-the-sun-travelling/28588#28588) The Sun is moving through the galaxy in a direction 60 degrees from the ecliptic, which is not aligned with the eccentricities of any planets.


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