This is a write up of Karvtal, a world of ice and deep forests, in the Galen Alpha planetary system, a setting for the Tyranny of the Daleks scenario, using the Second Edition of the Doctor Who Roleplaying Game from Cubicle 7.
Third Planet of Galen Alpha
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| Karvtal, seen from space during the northern hemisphere's summer |
Mass : 0.94 x Earth
Diameter: 14,282 kilometres
Density: 3.68 grammes per cubic centimetre
Average temperature: -27.7 degrees Celsius (minimum -110 degrees Celsius, maximum 13.2 degrees Celsius)
Rotational Period: 2.44 days
Orbital Period: 1.5 years
Surface gravity : 0.749 g
Semi-Major axis of orbit around Galen Alpha : 1.35 AU
Eccentricity of orbit : 0.0182
Inclination of orbit: 0.2 degrees
Obliquity : 8.57 degrees
Karvtal is a world balanced on the edge of ice.
It is the outermost of the three inner terrestrial worlds of Galen Alpha, orbiting beyond the warm seas of Galentor and just outside the Cyndor Belt. It is a broad, cold super-terrestrial world of low density and expansive horizons, a place of deep forests, glacial valleys and immense storm systems that coil across entire hemispheres. Though less obviously hospitable than Galentor, and receiving only around two-thirds of Galen Alpha’s sunlight, Karvtal possesses a quiet grandeur and a geological vitality that make it one of the most compelling destinations in the system.
Formation and Early History
Karvtal formed in the outer region of the inner system, beyond the optimal temperate zone but well inside the domain of the gas giants. During the protoplanetary era it accreted from volatile-rich planetesimals, giving it a significant inventory of water ice alongside silicate rock and metal.
Unlike the inner desert world Pentaurus, Karvtal retained much of its primordial water. Early heavy bombardment scarred its crust, and several of the largest impact basins remain visible today beneath ice sheets and sedimentary plains. As the young Galen Alpha brightened, Karvtal never quite crossed into full habitability; instead, it stabilised in a prolonged glacial regime.
Its iron core remains partially molten, sustaining a magnetic field that protects the surface from stellar radiation. Slow mantle convection drives modest tectonic activity, enough to renew the crust over geological timescales without plunging the planet into global resurfacing events.
Differentiation occurred early, producing:
A metallic core capable of sustaining a dynamo
A convecting mantle
A thick lithosphere, particularly in colder high-latitude regions
Its lower gravity, at roughly three quarters of Earth’s, allows mountains to rise somewhat higher relative to crustal strength, while atmospheric circulation behaves on a broader scale due to its longer rotational period.
Orbit and Seasonal Character
Karvtal circles Galen Alpha once every year and a half. Its orbit at approximately 1.35 AU is nearly circular and lies very close to the system’s primary plane. With only a modest axial tilt of just under nine degrees, seasonal contrasts are muted. Winters are long and severe at high latitudes, but not wildly variable year to year. Summers are brief and cool.
The planet rotates once every two and a half days, giving it broad atmospheric circulation cells and expansive storm systems rather than rapid, tightly wound weather patterns. From orbit, cloud bands sweep across ocean basins in slow spirals, sometimes stretching thousands of kilometres. Climate patterns are driven more by latitude and ocean circulation than by extreme seasonal swings.
The maximum temperature ever recorded at the equator, in sheltered dark-soil basins during peak insolation, is 13.2 degrees Celsius. That is exceptional. Most of the planet remains below freezing for much of the year.
Composition and Atmosphere
Surface atmospheric pressure 116 kPa at sea level
Karvtal Atmosphere (by volume)
• 74.8% Nitrogen (N₂)
• 20.6% Oxygen (O₂)
• 1.9% Argon (Ar)
• 1.2% Carbon dioxide (CO₂)
• 0.45% Water vapour (variable, equatorial average)
• 0.04% Neon
• 0.01% Methane (biogenic and geological trace)
• trace krypton, xenon and others
Karvtal is slightly larger in diameter than Earth but less massive, giving it lower surface gravity. Its bulk density indicates a silicate mantle and iron core comparable in structure to Earth’s, though proportionally somewhat more volatile-rich in its crust.
Its atmosphere is thicker than Earth’s, dominated by nitrogen with substantial oxygen and an elevated carbon dioxide fraction. Surface pressure is moderately higher than Earth’s, enhancing greenhouse retention and helping keep equatorial oceans from freezing solid.
The oxygen content makes the air breathable to humans. The higher carbon dioxide level would feel noticeable but not immediately harmful. Radiation levels at the surface are slightly less than Earth’s, moderated by both atmosphere and magnetosphere.
Climate and Weather
Karvtal’s climate is defined by latitude.
At the poles, ice sheets extend for thousands of kilometres, their winter temperatures plunging into extreme cold. These ice masses are kilometres thick in places and grind slowly outward, calving into steel-dark seas.
Mid-latitudes host vast taiga forests: dark, conifer-like growths adapted to short summers and long winters. Snowfall is common, and seasonal thaws create sprawling meltwater plains.
The equatorial zone contains cold oceans that remain largely ice-free due to oceanic heat transport and atmospheric greenhouse warming. Sea ice forms seasonally along margins but rarely seals the oceans entirely.
Storms are large and slow-moving. Low-pressure systems build over ocean basins and drift for days, bringing heavy snowfall inland. Blizzards can persist across continental interiors, reshaping dunes of powder-fine snow.
Lightning storms are rare but spectacular, often associated with volcanic ash plumes.
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| Karvtal's orbit around Galen Alpha |
Surface and Geological Activity
From space, Karvtal is striking.
Broad dark continents dominate the visible hemisphere, interspersed with cold blue oceans. Around 41% of the surface is covered by oceans. The mid-latitude forest belt appears almost black-green, absorbing what light it can. Polar caps gleam white, edged by jagged ice shelves.
Several major mountain chains arc across continents, their peaks perpetually snow-clad. Deep fjord systems carve high-latitude coastlines where ancient glaciers have retreated and advanced over millennia.
A vast tectonic rift valley splits one major landmass. Here, geothermal heat keeps the ground seasonally ice-free, and fumaroles vent steam into sub-zero air. These geothermal corridors are biological refuges and ideal locations for exploration.
Volcanism exists but is moderate. Basaltic shield volcanoes occasionally breach ice sheets, melting temporary lakes that refreeze into chaotic, fractured ice plains. Seismic activity is steady but not catastrophic; earthquakes and tremors ripple through crustal fault lines as mantle convection continues its slow work.
Impact craters are visible in older terrains, though many have been softened by ice and erosion. Some subglacial basins likely conceal preserved impact structures beneath kilometres of ice.
The Biosphere
Life on Karvtal is not exuberant. It is enduring.
The dominant terrestrial lifeform is the Talarith tree analogue: dark-spired, antifreeze-bearing forest giants that form dense taiga belts. Their pigments are tuned for lower light levels, and their vascular systems resist freezing.
Beneath them grow symbiotic vines and mineral-harvesting microbial mats that build soil from bare rock.
Fauna includes migratory herbivores adapted to snow and cold, pack-hunting predators that navigate blizzards by seismic sensing, and burrowing organisms that aerate frozen ground.
In the oceans, cold nutrient-rich waters support large filter-feeding organisms and extensive kelp-like reef systems anchored to basalt shelves.
And in the polar ice lives something rarer and more mysterious: large glacial predators that enter metabolic suspension during deep winter and roam subglacial caverns near geothermal rifts. They are few, ancient, and difficult to study.
Life survives here through:
• Antifreeze biochemistry
• Slow metabolism
• Symbiotic nutrient exchange
• Seasonal dormancy
• Efficient oxygen utilisation
Karvtal’s ecosystems operate on longer timescales than Earth’s. Growth is slow. Extinction is slower.
From Velnara
From the surface of its moon Velnara, tidally locked in its orbit, Karvtal dominates half the sky. Its polar caps are brilliant white arcs. Dark forest belts are clearly visible. Storm systems drift visibly over days. Occasional volcanic plumes rise like faint scars against the snowfields.
The view is serene and forbidding at once.
Surface Exploration and Points of Interest
Karvtal is a world of brooding skies and expansive wilderness. For time travellers, it offers a range of compelling environments:
The Hadrien Rift
A tectonic fracture zone thousands of kilometres long, where crustal plates are slowly pulling apart. Steam vents, shallow magma chambers and geothermal fields dot the landscape. Subsurface lava tubes could hide secrets or long-lost installations.
The Veloran Glacial Fjords
Immense ice-carved inlets where sheer cliffs plunge into dark waters. Subglacial melt channels occasionally collapse, creating sudden catastrophic floods.
The Eos Thermal Basin
A high-latitude volcanic caldera region where geothermal warmth maintains a microclimate of evergreen forest within a snowbound plateau.
The Cyndor Impact Field
A chain of partially eroded impact craters from early belt debris, now forming interconnected lakes and mineral-rich basins.
The Nareth Expanse
A continent-spanning ice shelf fractured by tectonic rifting, beneath which lies a subglacial ocean connected to geothermal heat sources. Beneath kilometres of ice, liquid water caverns and microbial ecosystems exist.
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| Karvtal seen from its south pole during the southern hemisphere's winter |
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