Your blue sky... or not

Okay, in the planet editor we'll have to deal with atmosphere, and therefore sky color.
The earth's sky is blue because of ozone. And a lot of refracition properties having to do with it - but it prevents us from all being fried by UV.
So unless your organism really likes UV, your atmosphere will need something to block it. If your organism wants to keep their flagella warm you'll also need a greenhouse effect. The concentrations of some of these greenhouse gases (and other gases) can and will influence the color of your sky.

Some examples:
Earth: Blue atmosphere
UV defense: Ozone
Greenhouse gases: CO2, N20, methane, water vapor, carbon monoxide, other gases I can't be bothered with.
Other: Oxygen, nitrogen, Argon

Venus: Hot, dense, opaque brownish atmosphere
Sulfuric acid, CO2, Nitrogen, and not a lot else.

That said, we need some research into other gases' refraction properties that would change the sky color. Some gas combinations probably wouldn't be very good for life as we know it, but planets are like popcorn: you get some duds.

Good idea.

i heard form somwhere that the sky color has to do with wavelength of the light and the distance from the source of it.... just what i heard

mike roberts wrote:

i heard form somwhere that the sky color has to do with wavelength of the light and the distance from the source of it.... just what i heard

No, sky color depends on
-light from the star(s)
-elements in the atmosphere

Mike, what you're referring to is red-shift: the spectrum we see from very distant stars is shifted towards red because the lower frequency red wavelength makes the long trip better than other visible wavelengths.
This does not effect near stars, because we are 8 light minutes from the sun, versus 4 lightyears from the next nearest star.

Mysterious_Calligrapher wrote:

Mike, what you're referring to is red-shift: the spectrum we see from very distant stars is shifted towards red because the lower frequency red wavelength makes the long trip better than other visible wavelengths.
This does not effect near stars, because we are 8 light minutes from the sun, versus 4 lightyears from the next nearest star.

That's not why, it's because of the doppler effect.
http://en.wikipedia.org/wiki/Redshift

Okay, movement as opposed to distance. Taking astronomy next year.
<3 wikipedia

Quick little bit here, not vitally important but I thought it might be good to keep in mind. What about sunrise/sets? When the light source passes through multiple layers we get the stunning displayes we all know. Even in atmospheres as thin as Mars' we have a little bit of it.

And correct me if I'm wrong, but in said situation krypton gives the sky a slightly neon greenish tint?

Tenebrarum wrote:

Quick little bit here, not vitally important but I thought it might be good to keep in mind. What about sunrise/sets? When the light source passes through multiple layers we get the stunning displayes we all know. Even in atmospheres as thin as Mars' we have a little bit of it.

And correct me if I'm wrong, but in said situation krypton gives the sky a slightly neon greenish tint?

Krypton's spectral lines come out to a white tint. None of the noble gases give off green light.
As for the skies, that's up to our graphics engine.

Scio... no noble gas gives off light. You need a steady electric current running through them for that.
Fluorine as a gas is greenish, though.
I haven't had a look at much of the heavier gases, though, as they would not be up in the higher atmosphere layers taking the brunt of the UV or creating the greenhouse effect.
(Ozone's atomic weight: approx. 48. Krypton's atomic weight: approx 84)

We also need to take into acount the temperature. Some planets are so cold that methane, one of the lightest gases, (and with one of the lowest boiling points) is solid.

I need to dig out my old organic chem notes and put up a table for melting/boiling points, if there isn't already one on the internet somewhere.

Mysterious_Calligrapher wrote:

We also need to take into acount the temperature. Some planets are so cold that methane, one of the lightest gases, (and with one of the lowest boiling points) is solid.

Titan, one of Saturn's moons, has liquid methane.
And methane clouds, giving an orangey tint. And it says life can live there, so it is a playable planet type.

Last time I read titan wasn't considered as a plausible harbor for life. The interest scientists had on it was due to
A: It has something liquid in its surface, rather uncommon.
B: This liquid is hydrocarbons, and as we know, hydrocarbons + nitrogen + lightning = aminoacids and the whole theory of how life began on the primordial soup.
However titan is a wee bit too cold for life, and would need oceans of something polar (instead of apolar methane) to dissolve such aminoacids (which are highly polar)

Also atmosphere color seems to have less to do with the absorption properties of a given gas and more with its scattering. See Rayleigh scattering:

http://en.wikipedia.org/wiki/Rayleigh_scattering

As a general rule, particulate tends to make atmosphere orange-brown.

Yeah, scattering is the main factor.

Well, I'm pretty sure that Titan is too cold for Life As We Know It, but as far as hypotheticals - this game is made of hypotheticals. We should be able to model the planet anyway... I'll start with a list of gases and their colors eventually.

Mysterious_Calligrapher wrote:

Well, I'm pretty sure that Titan is too cold for Life As We Know It, but as far as hypotheticals - this game is made of hypotheticals. We should be able to model the planet anyway... I'll start with a list of gases and their colors eventually.

However, we want to set up what we know first. The point of the game is realism, and we can't claim that if we make up the chemistries. It's gonna be hard enough to get the seperate styles of technology up during the interstellar phase (Assuming a pseudo-terran homeworld), let alone predict the route life would take with different chemistries altogether.

And yes, gases plus their colors would be nice.

And I could have sworm their was a gas that gave off a neon-greenish color. Hrm...

Could we do what we are doing for gas for other forms of matter too? So seas of different materials will be different colours, and the land, too. Solids' colour is important if we want any variation in planet colour. But living things can build/grow on the planet, changing the colour viewed from space.

Just pointing this out, now back to the discussion.

Specificity, Rex - your gas is not glowing on it's own. Though, now that I think of it, there is a greenish gas somewhere, I'm pretty sure - it's just not noble.
I'm going to have to do this more or less one element at a time, so it will take a while. And while we need to model LAWK first, the fact that there are propositions and conjectures about the possibility of life on a planet/moon similar to titan means that we should be having a look at it. And the fact that there is research means that we should be able to make the planet in our editor, regardless of life's specifications on it.

Mysterious_Calligrapher wrote:

Specificity, Rex - your gas is not glowing on it's own. Though, now that I think of it, there is a greenish gas somewhere, I'm pretty sure - it's just not noble.

I know that, I said "neon green-ish gas," I never mentioned anything about glowing. I don't know of any gas that glows without any sort of super-heating or electrical input.

I only though it was Krypton because I remembered that under severe pressure it crystalizes, and those crystals are green. At least I think. It's been a long time since I've studied this.

Tenebrarum wrote:

And I could have sworm their was a gas that gave off a neon-greenish color. Hrm...

Okay, my chem major proposes chlorine. I'll be looking through the noble gases first.

Apart from phosphorecent stuff such as phosphorous, only radioactive stuff may glow spontaneously. Plutonium is known to get hot enough to look incandescent due to its decay, and if it goes critical you get that blue chekerov (spelling?!) effect glow around it due to radiation directly. Alas, plutonium is not naturally found in nature.

And sea color depends on the atmosphere color. the sea itself is pitch-black because all light that refracts into it eventually gets absorbed. The only exception to this is shallow waters where scattering might reflect light back and give it a greenish/blue hue.

Djohaal wrote:

Apart from phosphorecent stuff such as phosphorous, only radioactive stuff may glow spontaneously. Plutonium is known to get hot enough to look incandescent due to its decay, and if it goes critical you get that blue chekerov (spelling?!) effect glow around it due to radiation directly. Alas, plutonium is not naturally found in nature.

And sea color depends on the atmosphere color. the sea itself is pitch-black because all light that refracts into it eventually gets absorbed. The only exception to this is shallow waters where scattering might reflect light back and give it a greenish/blue hue.

I was thinking of a neon-greenish color.

Oh yeah, doesn't hydrogen three glow?

Tenebrarum wrote:

Djohaal wrote:

Apart from phosphorecent stuff such as phosphorous, only radioactive stuff may glow spontaneously. Plutonium is known to get hot enough to look incandescent due to its decay, and if it goes critical you get that blue chekerov (spelling?!) effect glow around it due to radiation directly. Alas, plutonium is not naturally found in nature.

And sea color depends on the atmosphere color. the sea itself is pitch-black because all light that refracts into it eventually gets absorbed. The only exception to this is shallow waters where scattering might reflect light back and give it a greenish/blue hue.

I was thinking of a neon-greenish color.

Oh yeah, doesn't hydrogen three glow?

I don't think so.

~sciocont wrote:

Tenebrarum wrote:

Oh yeah, doesn't hydrogen three glow?

I don't think so.

Yes, Tritium/Hydrogen-3 glows, but not of itself. It causes phosphors to glow due to electron emission from radioactive decay (didn't do chemistry for quite a while), tho it's extra rare. The world demand is around 300 grams, and that's over 300k $ Hydrogen-3 is mainly formed by reaction of cosmic rays with the atmosphere, I think.

So kids, if the atmosphere has phosphors and craploads of Tritium, it glows =D

Anything with an unstable nucleus will decay.
Some phosphorous compounds glow, but most of them are waaay too massive to be found in an atmosphere, unless we have a boiling-hot planet.
Please remember that we're looking at potential gases here.
Tritium (3h, not H3, which would be impossible) sounds like a good idea. Wiki is here, so long as we're collecting data.

Also, Uteen - specifying solid color on the basis of chemical composition would be a program of its own. An insanely complicated one. So we're using brushes, as discussed in the thread about TO's - Plants will auto-color in response to the star's intensity, and anything that is not a plant or a organism can be painted.
However, we may start up a seperate thread about liquids - water is conveniently colorless, but other liquids that could potentially be "pools" on our planets will not be.

Mysterious_Calligrapher wrote:

Anything with an unstable nucleus will decay.
Some phosphorous compounds glow, but most of them are waaay too massive to be found in an atmosphere, unless we have a boiling-hot planet.
Please remember that we're looking at potential gases here.
Tritium (3h, not H3, which would be impossible) sounds like a good idea. Wiki is here, so long as we're collecting data.

Also, Uteen - specifying solid color on the basis of chemical composition would be a program of its own. An insanely complicated one. So we're using brushes, as discussed in the thread about TO's - Plants will auto-color in response to the star's intensity, and anything that is not a plant or a organism can be painted.
However, we may start up a seperate thread about liquids - water is conveniently colorless, but other liquids that could potentially be "pools" on our planets will not be.

Actually, water really is blue, and Tritium should be ³H or H-3 if you don't want to deal with [/sup]. Properties of water.