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When viewed from their planet, are moons always the same colour as ours? Or is there a variation? What other colours might be possible and what causes the differences in colour?

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    $\begingroup$ Our moon isn't always the same color when viewed from our planet. $\endgroup$ – Michael McGriff Jan 14 '15 at 18:03
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    $\begingroup$ @RBarryYoung Actually that's not true. The atmosphere could potentially change the color significantly. $\endgroup$ – Tim B Jan 14 '15 at 18:07
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    $\begingroup$ @Tim B: Yes, the moon can appear orange (e.g. harvest moon rising in the fall), blood red (lunar eclipse), or even blue in some rare atmospheric conditions. (Some people would like you to believe that the expression "blue moon" has to do with the calendar, but that's a myth created by people who don't get outside enough at night.) $\endgroup$ – jamesqf Jan 14 '15 at 18:42
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    $\begingroup$ The Mass Effect game series, particularly the first one, often mentions planet colors in relation to the mineral content of that planet. You can extend this to moons for what materials to use for what colors. I'm pretty sure the planet descriptions are in the ME wiki. $\endgroup$ – ajp15243 Jan 14 '15 at 19:54
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    $\begingroup$ Also, as an aside, it's just a coincidence that our moon happens to be tidally locked, and thus we always see the same side of the moon throughout the day - on other planets, the face of the moon can change too. $\endgroup$ – Zibbobz Jan 15 '15 at 17:54
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More or less they can be of any colour.

The colour of the moon from the point of view of someone who is in the planet is determined by four factors: The moon material, the atmospheric composition, the sun colour and the observers eye sensibility.

  • First the colour of the sun, normally determined by the temperature. You probably want it to be white/yellow or white/xxx so it doesn't change the planet light.
  • The moon material will be the thing you can change more as you can choose many materials with different colour reflections. For example iron oxide for red (like Mars).
  • The atmospheric colour is the final filter, so you can have a brown moon and if you have a green atmosphere, the moon will be more green than brown. The colour of an atmosphere can be because of its components in different layers so maybe you can have a coloured sky but still have a breathable atmosphere in lower level.
  • The sensibility of the observers eye can also filter what it perceive. Humans can see a range of frequencies that we call "visible range", but other animals can have other ranges for example bees can see in ultraviolet range. This can be affected by the sun light as it's normal for life to evolve to be more sensible to the range of light it have.

So you can combine each of the three factors to create the colour you want.

About the colour of the moon, you can search for mineral pigments to found many pigments (colours for your moon) that are more or less naturals. For example you have: lapus lazuli for blue, iron oxides for red / ochre even green (see http://www.earthpigments.com/sof-green-pigment/).

I found a page in which you can find minerals by colors: http://webmineral.com/help/Color.shtml

You can see a link about what animals see in following link http://www.colormatters.com/color-matters-for-kids/how-animals-see-color.

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    $\begingroup$ Additionally moons can have different colours in different areas if you can find ways to explain varying mineral compositions. $\endgroup$ – Tim B Jan 14 '15 at 18:08
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    $\begingroup$ @TimB Cf. The mare of our Moon (though they are mostly just different albedo, I guess) $\endgroup$ – Hagen von Eitzen Jan 14 '15 at 22:36
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    $\begingroup$ A potential fourth factor is the colour sensitivity of the observer. We could expect the perception of a native to the planet to not be as influenced by the colour of the sun or the atmospheric colour, because if they evolved any ability to differentiate colour it would have been with those two factors affecting the colour of everything they can see, and so making it beneficial to have eyes that were particularly good at differentiating between items that could e.g. look like different shades of red to us due to their red sun. $\endgroup$ – Jon Hanna Jan 15 '15 at 17:19
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    $\begingroup$ @JonHanna I totally agree with you. I've updated my answer to reflect it. $\endgroup$ – PhoneixS Jan 15 '15 at 17:30
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    $\begingroup$ It's an interesting world-building point in term of planets with both native and visitor populations; the native poets have long struggled for new ways to describe the delicate ever-changing filigree pattern that covers the smaller of their two moons while the visitors just see a hazy orange blob. $\endgroup$ – Jon Hanna Jan 15 '15 at 17:34
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Of course no.

A satellite colour is the combination of

  1. the colour of incident light (depends on the star)
  2. albedo colour parameters (depends on the material of the satellite itself)
  3. atmospheric filtering.

Since there are blue, white, yellow, orange and red stars, that's a lot of possibilities.

With only our own Sun (orange), and no atmospheric filtering (since these photos are from space), we have these:

Moons image

(Source: https://commons.wikimedia.org/wiki/File:Moons_of_solar_system_v7.jpg , Original source: solarsystem.nasa.gov , more details in original page)

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    $\begingroup$ And this is just what we have in our solar system -- there are other possible materials that could form a satellite and have different colors. No reason, for example, that a major impact tearing off a chunk of Mars (same manner as our moon is believed to have been formed, or at least one explanation thereof) couldn't result in a red moon. $\endgroup$ – Kromey Jan 14 '15 at 17:36
  • $\begingroup$ Do you have some attribution for that image? $\endgroup$ – paqogomez Jan 14 '15 at 18:40
  • $\begingroup$ @paqogomez Fixed $\endgroup$ – Envite Jan 14 '15 at 18:50
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I'd think much variation. Our moon is a pretty barren rock with some lava flow colouring it (lava flow is the dark spots. The other side of the moon mostly lacks this and appears much more solid white apparently).
a couple examples:

IO (moon of jupiter), would appear very yellow in the sky due to it's sulhpur composition.

Europa (another jupiter moon) is mostly ice and it's colour would be more white along with a red center.

Triton (Neptune) has a nitrogen atmosphere and will have a blueish colour

Tethys (saturn) has a yellow / sand colour to it.

A good portion of moons will look barren as ours, but there can easily be colour variations from simple make-up. Most of these pics can be readily found on google.

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    $\begingroup$ "white along with a red center"? $\endgroup$ – Ghanima Jan 14 '15 at 18:44
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    $\begingroup$ Sorry, poor description. Europa is covered with Linae...cracks in the ice that allows minerals and other water come to the surface. They are more predominant around the equatorial regions, giving the image of white polar regions with red streaks around the equator. White with red center as I wrote makes it sound like a gobstopper / jawbreaker. Ha! $\endgroup$ – Twelfth Jan 14 '15 at 18:55

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