# arrival time (until-wall)

The time until drift moves a parameter to a wall of its window, at the current rate.

- Computed level: L12 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: agency

## Emergence
**Emerges from:** [drift](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-drift.aimless), [parameter](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-parameter.condition), [wall](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-wall.range-end), [window](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-window.range), [rate](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-rate.speed), [current](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-current.present), [time](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-time.dimension), [motion](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-motion.movement)

**Through:** Distance to a wall divided by the rate of drift toward it gives a time, and that time, not the distance, is what decides whether any correction can still land. A near wall approached slowly can leave more time than a far wall approached fast.

**Novel properties:**
- distance converted into time
- the quantity a correction must beat
- a wall that is approaching rather than standing

## Examples
- Before a hurricane's landfall the US National Hurricane Center publishes the earliest reasonable arrival time of tropical-storm-force winds, telling each stretch of coast how long it has left to prepare. *(meteorology)*

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-arrival-time.until-wall*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-arrival-time.until-wall.json*  
*Every definition provably resolves to space, time, energy and pattern.*