SolTrop v12.4 • Galactic Edition

Abstract

SolTrop is a complete time-and-date standard built exclusively from the two observable physical cycles of any planet: axial rotation relative to its star and orbital revolution around that star.

The clock is a pure decimal fraction of one mean solar day (or orbital period for tidally locked worlds). The calendar uses continuous day-of-year numbering (DDD) that begins each year at the exact vernal equinox (or sub-stellar meridian crossing for tidally locked planets). The epoch is the first vernal equinox after SN 1987A. Era names are Witness Era (after) and Echoes Era (before) — no negative years. All planets share the same galactic year count.

1. Motivation

The current Gregorian/UTC system mixes arbitrary divisions (24/60/60), political time zones, daylight-saving shifts, and a year start unrelated to seasons or physics. SolTrop removes every non-physical element.

2. The SolTrop Clock

One mean solar day is divided into a pure base-10 fraction:
t = seconds since midnight / 86400
Displayed as decidays.centidays.millidays (e.g. 4.37.85). Solar noon is always exactly 0.50000 at the reference meridian.

3. The SolTrop Calendar

Format: Era YYYY-DDD.fraction (non-tidally locked planets) or Era YYYY.fraction (tidally locked planets)
New year begins at the exact vernal equinox (or sub-stellar meridian crossing for tidally locked worlds). Seasons are permanently locked where axial tilt allows.

4. Cosmic Epoch and Era Naming

Witness Era Year 1 is the first vernal equinox after the SN 1987A neutrino burst (21 March 1987, 03:52 UTC). All dates after are in the Witness Era; before are in the Echoes Era.

4.5 Standardized Time Zones (18° / 0.05-day system)

Fixed 18° longitude zones with exactly 0.05 decimal day offsets (½ deciday ≈ 1.2 old hours). Solar noon aligned to 0.50000 in zone centers on vernal equinox. 20 zones total (±9°, ±27°, ..., ±171°), no DST, optional display. Max drift ±0.025 days (~36 min) at edges. Devices show both reference and local zone time.

5. Interplanetary Extension

Every world uses its own local rotation/orbit physics but shares the same galactic Witness/Echoes year count. Tidally locked planets use orbital fraction instead of DDD because there is no separate day-of-year cycle.

6. Advantages

Trivial base-10 arithmetic — no 60-to-24 conversions
Seasons permanently correct where applicable
No politics, no arbitrary weeks or months
Scales instantly to any colony
Shared cosmic origin story from SN1987A

7. Reference Implementation

This website is the live reference. Open-source, offline, works in any browser.

8. Conclusion

SolTrop is the first timekeeping system designed for an interstellar species. By anchoring the year count to the moment we witnessed SN 1987A and locking the calendar to each world's own physics, we achieve perfect fidelity while giving every future human a shared cosmic timeline.

Technical Appendices

Appendix A: Conversion Formula

daysSince = (gregDate - EPOCH) / 86400000
solYear = floor(|daysSince| / 365.2425) + 1
ddd = floor(|daysSince| % 365.2425) + 1

Appendix B: Time Zones

zoneIndex = round(longitude / 18)
offset = zoneIndex * 0.05  // decimal days

Appendix C: Tidally Locked Planets

fraction = (currentTime % orbitalPeriod) / orbitalPeriod
display as Era YYYY.fraction

Appendix D: Precision

The 365.2425-day average keeps the vernal equinox stable for >3,000 years. Orbital periods for exoplanets are fixed at discovery values.

Key Improvements Needed for Successful Adoption

Priority	Improvement	Why Critical	Effort
★★★★★	Mandatory dual-display mode (Gregorian + SolTrop side-by-side for 20+ years)	Removes “all or nothing” fear	High
★★★★★	Unified date format across all planets (always YYYY-DDD.fraction)	No confusion in interplanetary communication	Medium
★★★★☆	Persistent user settings (localStorage for longitude & preferences)	Feels like a real tool	Low
★★★★☆	Official reference API (JSON endpoint for any planet)	Developers need integration point	High
★★★★☆	Governance & versioning plan (IAU responsibility, drift correction process)	Builds trust	High
★★★☆☆	Better local solar alignment options	Reduces 36-min drift complaint	Medium

Proposed Goals, Rules, Regulations, and Governing Body

Governing Body: The International Astronomical Union (IAU) shall be the sole authority responsible for maintaining, updating, and certifying the SolTrop standard.
Epoch Definition: “The first mean vernal equinox (of date) after the arrival of the SN 1987A neutrino burst at Earth” (currently 21 March 1987, 03:52 UTC; IAU may refine the precise second if better data emerges).
Year Count: Shared galactic count based on Earth’s tropical year progression since the epoch. All planets and colonies use the identical Witness/Echoes year number.
Drift Corrections: When cumulative drift reaches ±0.5 day (or IAU-determined threshold), the IAU may propose and vote on a future re-alignment epoch. Corrections are scheduled decades in advance and do not retroactively alter prior timestamps.
New Bodies: IAU approves addition of new planets/moons/habitats upon publication of reliable orbital/tropical-year parameters and consensus on the reference point for year start (vernal equinox or equivalent).
Updates: IAU publishes revisions every 50–100 years (or sooner if drift accelerates), via official resolutions and updated reference values.
Goal: Establish SolTrop as a long-term auxiliary standard for interplanetary and interstellar operations, complementing (not replacing) civil time systems on Earth.

SOLTROP

Witness Era 39