Ammoniac Atmosphere

The Ammoniac Atmosphere defines the frigid gas envelopes of outer-Continuum worlds — immense, swirling chemistries of hydrogen and ammonia wrapped in perpetual twilight. It is the archetype of Jovian cold worlds, where heat is a memory, color comes from chemistry, and clouds build mountains that float.

Composition and Structure

Ammoniac skies are dominated by gaseous NH₃, comprising up to 60% of the atmosphere by volume. Hydrogen and Helium form the carrier gases, providing buoyancy and moderating convection, while trace Methane deepens the blue hue of the clouds. The result is a stratified, layered gas ocean — each tier a different phase of ammonia and water ice suspended in supercritical hydrogen.

Layer	Primary Composition	Approx. Temp. (K)	Notes
Upper Stratosphere	NH₃ vapor, H₂, He	110–130	Pale blue, semi-transparent; violent winds.
Middle Troposphere	NH₃–H₂O clouds	130–150	Thick storm belts; ammonia snow.
Deep Mantle	Supercritical H₂, NH₃, CH₄	150–180	Luminous lightning discharges; ionized gas layer.

Environmental Characteristics

• Pressure: 12–40 atm — increasing exponentially with depth.
• Temperature: 110–180 K — stable across the troposphere.
• Visuals: Blue-gray with violet undertones; constant banded cloud motion.
• Acoustics: Deep resonant thunder; infrasonic wavelengths dominate.
• Aroma: Sharp and alkaline — detectable even through vacuum-rated filters.

Atmospheric Phenomena

• Ammonia Snow: Microscopic NH₃ crystals fall from mid-cloud decks, evaporating before surface impact.
• Electro-Ammonic Storms: High-pressure lightning arcs between layers, forming kilometer-wide plasma curtains.
• Floating Icebergs: Buoyant clumps of ammonia-water ice drift through mid-atmosphere, acting as seeds for cloud vortices.
• Acoustic Rings: Standing wave patterns circling entire planets; believed to modulate magnetic fields.

Biochemical Potential

While hostile to standard biology, Ammoniac environments support theoretical chemoautotrophic life utilizing the “hydronitric cycle.” In this cycle, organisms synthesize energy by converting NH₃ and H₂ into amino analogs under high pressure, producing faint infrared bioluminescence. Speculative forms — nicknamed drifters — are vast, translucent sacs kilometers wide, feeding on storm energy.

Thermal and Reflective Properties

Ammoniac worlds reflect ~60% of incoming light due to their dense clouds, making them bright to telescopes but dim in infrared. The Grand Archive Division of Exoatmospherics notes that their refractive spectra are stable enough to serve as galactic calibration standards for optical sensors.

Research and Cultural Notes

Ammoniac-class atmospheres are favored in Continuum hydrostatic simulations for their dynamic equilibrium — self-balancing storms that persist for centuries. The world of Ammonis is often used in training for long-duration aerostat navigation; its upper decks are considered “flyable oceans.” Continuum poets call such skies “the cold lungs of creation.”

Associated Gases

Ammonia • Hydrogen • Methane • Helium

See Also

• Cryo-Oxygen Atmosphere
• Methal-Nitric Atmosphere
• Continuum Atmospheric Compendium