24 hours vs 10 Blocs
Two slicings of the same day — the one inherited from Babylon, and the ATS one. Everything between the hand and 12 o'clock is already gone.
Why look at both side by side?
Two questions become visible only with both dials present:
- How much of the day is left? Read the empty arc, not the digits. On a 10-Bloc dial, "half left" is the diameter — instantly legible. On a 24-h dial, it takes a beat to subtract hours from 24.
- What proportion of the day has a given task consumed? ATS makes this a percentage by construction (1 Centi = 1 % of a day). The 24-h dial requires arithmetic.
Detailed rationale: philosophy §2.3. The two systems are equivalent in information; they differ in the cognitive load needed to extract everyday questions.
One Bloc lasts ≈ 2 h 24 min. The right dial therefore appears to spin faster than the left one (10 turns per day vs 24).
Reading guide
| Question | 24-hour dial | 10-Bloc dial |
|---|---|---|
| What time is it? | Read hours + minutes (two numbers, base-60). | Read the Bloc (one number) and the Centi after the dot (percent of the day). |
| How much of the day is left? | 24 minus the current hour; estimate minutes. | 10 minus the Bloc reading; the empty arc shows it visually. |
| "Half the day is over" | Hands at 12:00 — easy. | Bloc 5 — exactly 12:00 UTC. Equally easy because the dial has 10 ticks. |
| "What percent of the day have I spent on X?" | (minutes spent) / (24 × 60) — arithmetic. | Centi delta — direct read. |
| "It's time to eat / sleep / stop" | Cultural anchors (12:00, 18:00, 22:00) — local norm. | Local culture maps to Bloc fractions (cf. Cities page). |
A short history of decimal time
ATS is not the first attempt at a decimal day. Two notable predecessors:
- French Republican decimal time (1793–1795). 10 hours per day, each subdivided into 100 minutes of 100 seconds. Mandated by decree, abandoned within 17 months for being out of phase with mechanical clocks and habit. Detailed in philosophy §4.1.
- Swatch Internet Time / @-beats (1998). 1000 ".beats" per day anchored to Biel Mean Time (UTC+1, no DST). A marketing artefact that nonetheless made one structural point: a single number per day is enough for asynchronous online coordination. Detailed in comparison §4.1.
ATS differs from both in scope (it is also a calendar via Kilo.Hecto.Deka.Kin, not just a clock), in epoch (the start of the lunar-landing day, fixed, not a tied-to-a-Swiss-timezone Mean), and in stability commitments (a versioned spec with a post-v1.0 freeze).
Component design rationale: analog-clock (annex). The full clock with 5 hands (Bloc / Centi / Milli / Beat / Blink) lives on the home page.