Basic astronomy
The Green Sun is not the center of this system; Skaia is. But since it’s not a star but a planet, it doesn’t play the role of a light source. Prospit, Derse and Alternia are in constant revolution around the blue planet. These revolutions have no effect on the seasons. In fact, the weather is pretty much the same all year long on Derse and Prospit (for more details, see the part about the climate). The revolution around Skaia is way longer for Derse. In one revolution of Derse, Prospit can do a little less than sixteen around Skaia. These revolutions were once used to measure years. However, it’s not the case anymore. I will make another post about this so stay tuned!
We won’t talk much about Alternia since the planet is dead but just keep in mind it was pretty similar to Earth, contrary to Derse and Prospit.
The purple and golden planets are quasi identical twins. If you walked the equatorial line of the planets at an average pace, it would take you 24 hours do return to your starting point.
Each planet also rotates on itself. The rotation takes 24 hours and that makes a day for the inhabitants. The rotation doesn’t affect the day/night change like it does on Earth. It basically only affects the scenery (see the Prospit and Derse section for more details).
The light source of Prospit and Derse
Since there is no sun to serve as a light source, Prospit and Derse are autarkic; they have an internal source of light. This mysterious magic system is auto regulated and the light it provides varies with the time of the day.
Prospit and Derse don’t have an atmosphere (if you read Homestuck, you’ve noticed the sky is always black), the sky the inhabitant see is a result of the magical light source.
Note: Earth’s blue sky is a result of molecule in the atmosphere and light waves (google it if you want) so no atmosphere = no blue sky.
On both planets, the default color of the sky is a pearly gray, almost white. It resembles the color of a uniform cloudy sky on Earth.
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SampleThe more the day passes, the more the light source dims itself... the sky therefore gradually takes its original color: pitch black.
Skaia is an exception to the rule; it is the only planet with an atmosphere and therefore, a blue sky. It has its internal light source as well, but the atmosphere gives it a blue coloration.
Prospit:Due to Prospit’s proximity with Skaia, the default gray (or black) is tainted by the blue hues of the planet. The closer to Skaia you are, the bluer the sky.
The planet’s rotation on itself causes a variation in shade during the day. Some parts of Prospit have the blue sky during the day while other parts have it during the night.
During the day, the sky is a variation of tints between pearly gray and pure blue. The night sky oscillates between pitch black and a very dark shade of blue.
May it be day or night, Prospitians can see Skaia in their sky (depending of the position of Prospit, of course). Then again, the rotation influences the moment of the day when Skaia is visible.
Derse:Since there is no light source anywhere near to tint the sky, the Dersites are stuck with the default pearly gray during the day and the inky black during the night.
However, the absence of atmosphere allows them to see the asteroids of the veil day and night. The rotation of Derse influences which part of the planet will see the asteroids at what point of the day. They have various sizes but most of them look like distant stars you can see even during the day.
Climate
Each planet has its own weather, which is not a seasonal variable like it is on Earth. All year long, the weather goes as the following:
Prospit is typically hot and humid. There is no wind on the golden planet. The only moment in history where there had been wind is the day the Heir was born.
Derse is colder but the air is drier as well. Mild winds often animate the surface of Derse.
Meteorological particularities:However, disturbances on the Green Sun’s surface (such as volcanic eruptions) affect the weather on the skaian planets. There is no pattern in these disturbances and can in no way be called seasonal changes.
On Prospit, the disturbances often provoke long periods of scorching heat. The Green Sun is also responsible for the rain that sometimes falls on the planet. On a yearly basis, there is a period when it rains non-stop for a few days to a few weeks straight. This period has no pattern whatsoever and happens when you least expect it. Storms can also be pretty violent on Prospit.
On Derse, the disturbances seldom bring rain... more than half of the time, the precipitations fall as snow. The climate is usually not cold enough so most of the snow just melts when touching the ground. At a few rare occasions, real snowstorms paralyzed the planet for a few days. Period of intense cold are not rare on Derse. Sometimes, the mild winds can turn into gusts similar in intensity to the ones on Prospit before the Heir’s birth.