Ra measures rotation.
1 Ra = 100 Vatime = 10,000 Vamin
TOOL 001 · PLANETARY TIME LAB
venuszeit.
A different rhythm. The same time.
A rotation is not a solar day.
VENUSRETROGRADE ROTATION
Fixed equatorial point · Noon
Spatial diagram: spheres and orbits are not to scale; no surface map. The equatorial point is fictional and axes have no tilt. Starts at local noon; does not show current planetary positions.
EARTH DAYS ELAPSED
Choose a time marker or start the simulation.
One time. Four perspectives.
Progress within the current cycleAfter a complete cycle, the bar returns to 0%. The total cycle count keeps increasing.
THE LOGIC BEHIND ITLonger than a year.
Longer than a year.
But which kind of day?
Venus rotates opposite to its orbital direction. This is why the Sun returns to the same place in the sky before Venus completes a full rotation.
From noon to the next noon.
TSun = (1 / Ra + 1 / Va)−1
8 Earth years ≈ 13 Venus years.
The units of Venus Decimal Time.
| Unit | Definition | Earth days | Earth minutes |
|---|
Basis & sources
The reference calculation uses a mean Venus rotation of 243.0226 Earth days from radar observations in 2006–2020 and orbital periods of 224.701 and 365.256 days. Measured values are not exact constants. Circular orbits, constant speeds and axes without tilt simplify the model. The light boundary shows geometric day and night, not brightness beneath the clouds of Venus.
Margot et al. · Spin State and Moment of Inertia of Venus ↗NASA · Venus Fact Sheet ↗NASA · Earth Fact Sheet ↗