All clocks are 30 seconds late
An essay arguing that clocks which only show hours and minutes are “on average 30 seconds late” because they truncate rather than round time prompts a broader look at how we interpret what clocks are telling us. Commenters contrast digital and analog mechanisms, debate whether time displays should represent exact instants or intervals (“at least this time”), and point out that rounding would trade a small reduction in average error for confusion about when events actually start. Many conclude that flooring to the last full minute is a pragmatic convention, and that when sub‑minute precision matters the real solution is simply to show seconds.
Analog vs Digital Clock Behavior
- Many note the article’s premise really concerns clocks that don’t show seconds and that truncate to minutes.
- Several argue large or well‑made analog clocks have continuously moving minute hands, so at e.g. 4:53:30 the hand is halfway between marks; no truncation problem.
- Others observe many cheap or electrically driven analog clocks “jump” the minute hand once per minute (often to save power), so they behave like digital truncating clocks.
- Station clocks (Swiss/German examples) are discussed: second hands often run fast then pause for sync; minute hands may jump.
Quartz, Mechanical, and What “Digital” Means
- Long subthread debates whether quartz clocks are inherently digital or analog.
- One side: quartz oscillation is analog, but always read via digital dividers, so timekeeping is digital; display may be analog.
- The other side: by that broad definition, mechanical escapements and even hourglasses also become “digital,” making the term less useful.
- Consensus: distinction between discrete vs continuous mechanisms is fuzzy and somewhat a matter of modeling convenience.
Flooring vs Rounding and Error
- Many say calling truncation “30 seconds late” is misleading: people understand “11:30” as a 60‑second interval, not a precise instant.
- Some point out the difference between average signed error (which can be zero under rounding) and average absolute or RMS error (non‑zero).
- Several argue flooring is practically preferable: you know a threshold has been crossed (e.g., 13:00 means at least 13:00:00).
- Rounding would blur thresholds: 13:00 could mean ±30 seconds, complicating meetings, deadlines, and synchronized events like New Year’s.
How Humans Use and Talk About Time
- Strong theme: clocks are tools for decisions (“has the meeting started?” “do I have time to do X?”), not scientific instruments.
- Many prefer coarse, conventional readings (“quarter past,” “half past”), often rounding hours or minutes in speech.
- Others want seconds everywhere (phones, PCs, thermostats, public transport) for tight timing of tickets, races, or broadcasts.
Reception of the Article
- Reactions range from “fun thought experiment” to “nonsensical / click‑baity.”
- Several say the piece overdramatizes a known, mostly harmless convention; others enjoy it as a way to think about precision, sampling, and time intervals.