Vanathul

Features

Locked rotation

An illustration of the day side of the planet, as seen from the sun

A diagram depicting how obliquity affects the habitable zones (seen from the side)

Vanathul, which is one name for the planet, has one face perpetually facing the sun. It has an axial tilt (obliquity) of 20° causing apparent vertical movement of sun over the period of a year. This means that the sun moves up and down to the same extent, but never sideways. This consequently results in the year having "seasons" where the sun is higher or lower in the sky. Near the terminator, the sun will only be visible for some times of the year.

The fluctuating warmth of the sun results in periodical melting of the snow and ice in the night, which in turn feeds into the sea or lakes. When the water eventually makes its way to the warmer subsolar it evaporates and feeds into the hot air stream blowing towards the night, starting the cycle anew.

Direction

North points to the axis of rotation, which can be useful for some purposes, but as this is a point somewhere between K'Shaal and Orn, confusion is to be expected when east and west switches direction when going from one continent to the other. Likewise south is all directions pointing away from this location.

For most working purposes the terms used are Sunward, Nightward, Leading and Trailing.

The two first of these are intuitive enough, refering to the direction of the sun an away from the sun. Alternate terms are Solar and Antisolar.

For Leading and Trailing, or Leadwards and Trailwards, a bit of astronomy is involved. Though it is not immediately apparent, the planet moves in an orbit around its sun. The direction of travel is sideways to an observet standing on the terminator on the planet, though it is reversed when switching from the northern to the southern hemisphere.

Given that the north pole is considered "up", the planet orbits in a counter clockwise direction, this means that while facing the sun on the northern hemisphere, leading is to the right, and trailing is to the left - like before, this switches for the southern hemisphere.

Again for brevity. On the northern hemisphere, where K'Shaal and Orn are located, "leading" is to the right when facing the sun, and "trailing" is to the left.

Skies

The sky on Vanathul is a deep blue, brightening towards the sun, and darkening further towards the night. The stars are mostly outshined by the sun, but towards the night a gradual increase in visible stars can be seen.

In what passes for the winter season, the sun draws closer to the horizon by several degrees of arc. This produces a reddening tint, and further darkens the nightwards skies.

Summers are conversely brighter, producing a bright blue sky, occluding a greater portion of stars, but when the weather is clear the brightest stars can still be seen.

Clounds vary based on their cover and elevation. They can be fluffy and pink or dark and brooding in the winter, or clear white in the summer. See the weather section for more info.

Common knowledge

The above analysis of the workings of the solar system is what is known by those specially interested in the subject. Most commoners have a lesser understanding, with many approaching it in an astrological sense.

External links

• Wikipedia's article on tidal locking.