Vector Shift — Kethra Day, Year, Seasons and Moons: Approval#
Approved by Briana • 18 September 2026
Briana approved the Kethra Day, Year, Seasons and Moons DRAFT in full. Claude asked whether she was happy with it; she replied "yes". The following are now canon:
| Element | Canon |
|---|---|
| Theia | About 5.5 billion years old, about 10% brighter than our Sun |
| Kethra's orbit | 1.06 AU from Theia; slightly stretched orbit (eccentricity about 0.03) |
| Sunlight | About 98% of Earth's, plus Hyperion's contribution |
| Year | About 368 Kethran days (about 399 Earth days) |
| Day | 26 hours |
| Axial tilt | 27°, giving four seasons of about 92 days each at mid-latitudes |
| Red-night season | About 4–5 months at the same point in each year |
| Current era | Lit winters: in the story's era, the red nights fall in the northern winter, so the south has red summers |
| Large moon | Bright; radius about 1,600 km; 414,000 km from Kethra; 30.5-day phase cycle. Capital name Pandia, frontier name Máni |
| Small moon | Dark; radius about 400 km; 95,000 km from Kethra; about 3.1-day phase cycle; rises about every 1.5 days. Capital name Ersa, frontier name Hati |
| Moons in the sky | Both moons appear nearly the same size |
| Tides | Stronger and more complex than Earth's |
| Eclipses | More frequent than on Earth, including eclipses of Hyperion |
| Calendars | The capital keeps a solar calendar; the frontier keeps a lunar calendar that falls a month out of step every 15–16 years |
The draft's working is part of the approved record. If one number changes later, recalculate the related figures from that working.
The cultural readings are included in this approval, as part of the draft. In the capital, the planet is circled by her daughters. On the frontier, Hati is the wolf chasing Máni.
Still open#
- A name for the system
- Kethra's size and gravity (assumed to be about Earth's)
- Climate zones, oceans and continents
Prepared by Claude.