Atmospheric Survey of Hypnale

Temperature maps

Rainfall Map

The atmosphere is far denser than on Earth, and problems with oxygen toxicity can come into play, with more than 600 millibars of oxygen. For a Terraform, over 500 mb can become toxic. However, any non hypnalaform breathing in the atmosphere will be killed by the chlorine and fluorine, long before oxygen levels build too high in their system. Because the air is denser, winds feel stronger. Hurricanes on the sunward side are seldom weaker than a class four. An additional10 mb of methane keeps the atmosphere toasty warm, with a global average of 300K, even after factoring in the chill of the darkside.

The atmosphere of Hypnale works similarly to the oceans. Warm air on the sunward side rises, creating a pressure difference, which draws in air from the starward side. The warm air is then pushed by more warm air over the terminator, where much of the moisture falls, and into the darkness of the starward side. Here, it cools, falls back towards the ground, and begins the cycle again. This current causes the planet to suffer from constant breezes. Seldom is their calmness in the air. Wind speeds at high altitudes are greater than what are found on most F3 worlds, sometimes flowing twice as fast as Earth’s jet stream.

In the upper atmosphere, water vapor is struck by the feeble ultraviolet radiation of Lalande 22185. This breaks it into hydrogen and oxygen. The oxygen atom combines with 02 to form ozone. The hydrogen interacts with chlorine to form hydrochloric acid. Chlorine is constantly being washed from the atmosphere, only to be replaced by the acid begin broken into hydrogen and chlorine on the sunward side. Rain mostly falls in the terminator, but snow does fall on the starward side. Because there is so little land in the starward side, the snow falls into the ocean and melts. Temperatures on the starward side of the planet can be 100K lower than the sunward side. Only constant movement of the atmosphere maintains a balance able to support life.

Weather on Hypnale seldom changes within its given climatic zone. The Terminator always sees rain, and the Sunward Zone is always baked dry. However, the heat from the sun that constantly cooks the Sunspot Desert also heats the ocean around the desert. This causes evaporation and the convection of the atmosphere forces the moisture starward. However, the differences in temperature between air and water causes great storms, shrouding the sunward coast of the Terminator in an almost perpetual cloud cover, with daily rain in some places.

The sky of Hypnale varies depending on which part of the planet one stands. On the sunward side, the sky is a pinkish-white, with the orb of Lalande 21185 always glowing above. The terminator suffers from pink and red skies. The darkside is a dark midnight blue. Directly below the sun, it appears to be red and white at the same time. At sharper angles, such as from the Terminator region, the sun is a pulsating, never-moving red orb, bathing the landscape in a reddish glow.

Hypnale suffered from a tidally locked climate. This means the climatic zones are not from the poles to the equator, but rather from the sun to the stars. The sunward side of Hypnale is under constant bombardment from the sun. Lands directly below the sun are baked dry, with rain never falling. The only source of surface water comes from springs that bubble up from underground rivers. The desert is also hotter than the hottest deserts on Earth, with temperatures averaging 340K or higher. Directly under the sun, no life lives. However, further away, where shadows are casts, life clings on to existence in the desert. The oceans beneath the sun are home to continuous storms.

The terminator is where most of the biomass congregates. It is a temperate area covered in vegetation. The closer sunward one travels, the more drought resistant the plants become, with scrubland ringing the Sunspot Desert. Since the terminator is bombarded with rainfall, it is also home to many swamps. The terminator offers a band of purple and ultraviolet that separates the sun and the stars.

The starward hemisphere is locked in perpetual night. Any creature living here must navigate by starlight. More often, they use infrared, echolocation, electric currents and even smell to navigate. The few landmasses on the starward side of the planet are locked in thick glaciers. The snow that falls here never melts. Glaciers build up and are forced into the ocean, where the icebergs are eventually absorbed by the ocean. The air temperature is well below freezing. Only the constant flow of water keeps the ocean from freezing.