The orbits and the rotations are both functions of a date, and the only date the
map ever asked for was this instant. So a view built on propagated ephemerides
showed a still picture: Earth turns 15 degrees an hour and takes a year to go
round, and a reader watching for a minute saw nothing move at all.
`TimeStore` is that date, at a rate the reader sets: real time, an hour a
second, a day a second, a month a second. It is read once a frame rather than
held in a signal — it changes continuously, and a signal changing sixty times a
second would ask the whole HUD to re-render for a number nothing is watching.
Changing the rate re-anchors rather than rewinding, so speeding up and slowing
down never jumps the sky, and "Back to now" returns to the world's own time.
Measured in the app, three seconds of watching in the Sun's system:
| rate | sky elapsed | Earth turned | Jupiter moved |
|---|---|---|---|
| real time | 0 | 0 | 0 |
| 1 h/s | 3.0 h | 45.12 deg | 0.0009 AU |
| 1 d/s | 3.0 d | (three full turns) | 0.0222 AU |
45.12 degrees in three hours is 15.04 an hour, which is Earth's own sidereal
rate, and Jupiter's 0.0222 AU in three days is its own orbital speed.
The rates are radio buttons, not toggles: they are one of four, and the native
control carries that to a screen reader and to the arrow keys with no script.
The date joins the strip only while the clock is running faster than the world,
since at real time it is today's, which the reader's machine already says.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
SenrokaiandClaude Opus 5
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