<p>There are no "commonly" used words to describe these things, but there are apt words developed in SciFi books.</p>

<p>The adverbs, <strong>spinward</strong> and <strong>antispinward</strong> would seem to do the trick. Inwards and ouwards will do for radial motion.</p>

<p>Movement towards towards the end of a spiral arm would be outwards and antispinward.</p>

<p>Trailing and leading can also be used to state relative position with respect to Galactic rotation (for objects not too far separated).</p>

CC BY-SA 3.0
2016-05-20T06:32:43.527Z
2016-05-20T06:32:43.527Z
ProfRob
<p>The <a href="https://en.wikipedia.org/wiki/Supergalactic_coordinate_system" rel="nofollow">galactic coordinate system</a> is usually used for galaxies. It is based on the galactic plane — approximately where the galactic disc is.</p>

<p>It uses galactic latitude (for the y-value of the objects) and galactic longitude (x and z values, based on the disc).</p>

<p>There is also a <a href="https://en.wikipedia.org/wiki/Supergalactic_coordinate_system" rel="nofollow">supergalactic coordinate system</a> used for superclusters.</p>

<p>Its equator is an invisible line called the supergalactic plane, which is the preferred distribution of galaxies in a supercluster.</p>

CC BY-SA 3.0
2016-05-19T19:09:15.367Z
2016-05-20T14:41:17.517Z
2016-05-20T14:41:17.517Z
Sir Cumference
<p>Are there commonly used names for objective directions within a spiral galaxy?</p>

<p>Central and peripheral describe objective directions, because the observer's frame of reference doesn't affect whether something is closer or farther from the middle.  "Clockwise" or "counterclockwise" don't work, because they depend on which side you're viewing from.</p>

<p>Are there names that can describe one object's location relative to another object, either in the galaxy's direction of spin or against it?  Or words to describe whether something is farther or closer out along a particular arm of a spiral galaxy? </p>

CC BY-SA 3.0
2016-05-19T18:57:48.253Z
Yes, see https://en.wikipedia.org/wiki/Galactic_coordinate_system
Sir Cumference
CC BY-SA 3.0
2016-05-19T18:58:25.550Z
Spinward and anti-spinward.
ProfRob
CC BY-SA 3.0
2016-05-19T19:17:02.140Z
It should be turnwise and widdershins....
James K
<galaxy><terminology>
Direction Names Within a Galaxy
Calvin Fisher
# Direction Names Within a Galaxy

(Asked by: username_0 on 2016-05-19)

Are there commonly used names for objective directions within a spiral galaxy?

Central and peripheral describe objective directions, because the observer's frame of reference doesn't affect whether something is closer or farther from the middle. "Clockwise" or "counterclockwise" don't work, because they depend on which side you're viewing from.

Are there names that can describe one object's location relative to another object, either in the galaxy's direction of spin or against it? Or words to describe whether something is farther or closer out along a particular arm of a spiral galaxy?

**Tags:** galaxy, terminology
> **Comments:**
> **username_1**: Yes, see https://en.wikipedia.org/wiki/Galactic_coordinate_system  
> **username_2**: Spinward and anti-spinward.  
> **username_3**: It should be turnwise and widdershins....  

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## 2 answers

### Answer by username_2 on 2016-05-20. Score: 2 | Accepted answer

There are no "commonly" used words to describe these things, but there are apt words developed in SciFi books.

The adverbs, **spinward** and **antispinward** would seem to do the trick. Inwards and ouwards will do for radial motion.

Movement towards towards the end of a spiral arm would be outwards and antispinward.

Trailing and leading can also be used to state relative position with respect to Galactic rotation (for objects not too far separated).


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### Answer by username_1 on 2016-05-19. Score: 2

The [galactic coordinate system](https://en.wikipedia.org/wiki/Supergalactic_coordinate_system) is usually used for galaxies. It is based on the galactic plane — approximately where the galactic disc is.

It uses galactic latitude (for the y-value of the objects) and galactic longitude (x and z values, based on the disc).

There is also a [supergalactic coordinate system](https://en.wikipedia.org/wiki/Supergalactic_coordinate_system) used for superclusters.

Its equator is an invisible line called the supergalactic plane, which is the preferred distribution of galaxies in a supercluster.


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