Valen-Homecoming

Planet Construction Laboratory
1 · Identification
2 · Physical Parameters
km
g/cm³

0.06–12 g/cm³. Above 12,000 km radius capped at 2.5 (gas/ice giant).

Earth 23:56:04 · Mars 24:37:22 · Venus 5832:00:00 · Jupiter 9:55:00

3 · Interior Structure
r/R
of core
g/cm³
4 · Orbital Parameters
AU
e
deg

Earth 23.5° · Venus 177.4° · Uranus 97.8°

5 · Surface & Ocean
%
%

Drives Clausius-Clapeyron water vapour. May differ from ocean coverage if partly frozen.

km
6 · Cloud Cover
%
Cloud type is calculated from atmospheric chemistry — you set the amount, the physics sets the type. Cloud cover drives the albedo–temperature feedback.
7 · Atmospheric Composition

Percentage of atmosphere. Water vapour is governed by temperature (Clausius-Clapeyron) and recalculated — entered value is an initial condition only.

— %
Below ~0.4% atmospheric water vapour, surface temperature can collapse below ~12 °C mean, triggering an ice-albedo glaciation cascade over weeks to months.
8 · Atmospheric Mass
%
Earth's entire atmosphere is ~0.000086% of its mass — about one millionth. Venus ≈ 0.0092% (~100×). This single input drives surface pressure, scale height and temperature.
9 · Star (manual — GGSC dropdown in next build)
L☉
K
10 · Additive Industrial Gases (optional · technosignature)

Gases added on top of the atmosphere — committed warming over 100 yr. Separate from the equilibrium engine (a transient flow, not bulk composition). CO₂ baseline is auto-derived from this world's own Block 7 CO₂ % (shown below the input). N₂O takes a user-set pre-industrial baseline (ppb) plus an industrial addition (ppt). Synthetics in ppt (to match EEA/IPCC/WMO data). Leave at 0 for a pristine world.

Synthetic halocarbons, SF₆ and NF₃ have no abiotic source — any detectable quantity is a technosignature. Committed ΔT is Earth-calibrated; on very wet/thick atmospheres the real effect is smaller. Note units differ per row: ppm for CO₂, ppb for the N₂O baseline, ppt for industrial N₂O and all synthetics.
11 · Biosignature Gases (optional)

PH₃ and DMS are assessed for the biosignature panel below (O₂, CH₄, O₃, H₂S, SO₂ and N₂O are read from the composition and additive-gas inputs above). Biosignatures are judged on disequilibrium and combination, not bare presence.

ppb
ppb
An airless world, awaiting an atmosphere.
Set composition to 100% · press Calculate
Input Calculated
—
—
—
Build sequence 1 of 3 — engine spine (Blocks 1–8). Blocks 9–16 (ice/ocean detail, interior, magnetic field, Jeans escape, bio/technosignatures, habitability, stellar evolution, spaceflight viability) and the live GGSC star dropdown follow in sequences 2–3.