The millisecond equals 0.001 second. Essential in computing, networking and high-speed photography. Human reaction time is about 200–300 ms. Video frame rates of 60 fps correspond to a 16.67 ms per frame.
Real-world: Ping to a local server: 5–20 ms. Game frame at 60 fps: 16.67 ms. Human reaction: 200–300 ms.
Read full millisecond reference →The day equals 86,400 seconds — the mean time for Earth to complete one rotation relative to the Sun (solar day). A sidereal day (relative to distant stars) is about 4 minutes shorter: 23 h 56 min 4 s. Most practical usage means solar day.
Real-world: International shipping: 2–7 days typical. Global work-week: 5 days in most countries. Human circadian rhythm: 24 h ± 30 min.
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