Purple Earths, Snowball Earths and other ELW variants

[frostypaw]

Having now wandered around and seen a fair few ELW I'm thinking they don't come in their natural variety.

We should naturally also have Purple Earths from when our atmospheric conditions were different resulting in different wavelengths being strongest in the sunlight hitting the earth - plants used to rely more on anthrocyanins and other relatives to produce energy than chlorophyll and as such plants were red to purple.

This is still seen expressed in plant genes All The Time Everywhere from red millet growing as weeds to purple beeches and maples.

How about that as an addition to the variety?

It's a tiny tweak in the planet terrain generation and would make for some fascinating sights - and which ELWs are red can be worked out by their age and the star's spectrum.

Snowball Earths may exist, but be proving as elusive as snowball AW's for me... but also why not?

 

[Twistednuke]

Arguably snowball Earth Likes already exist, as they would simply appear to be a frozen other world with high amounts of water ice. However, I like the idea of alternate photosynthetic compounds. "A planet orbiting an F2 star (red line) has more blue light at the surface, whereas Earth and the K2 star planet receive more red light. Planets around M stars receive much less visible light but much more infrared light." [http://www.nasa.gov/centers/goddard/news/topstory/2007/spectrum_plants.html]. Here we can see the incentive for chlorophyll substitutes as other stars have different peak spectra than out own.

Additionally the game should reflect alternate biochemistries, although some minor changes would not be visible from space (for example, substitution of phosphorus for cyanide) some would. I believe we already have rare worlds that have high enough amounts of ammonia for microbes to replace water with liquid ammonia, however Hydrogen Fluoride is also an excellent option as it behaves very similarly to water. Additionally the game could have very rare boronogenic life, this would be life that substitutes carbon for boron, with worlds completely unlike ELWs.

 

[frostypaw]

Yay And the joy is all the development time is in tweaking a few colour parameters based on a few system stats.