Millimeter per Hour to Mile per Second

Millimeter per hour measures extremely slow movements in millimeters over an hour. Used for minute geological and material changes.

1 mm/h = 0.001 m/h = 0.0000001 km/h = 0.000000278 m/s.

To m/s: ÷ 3,600,000. To cm/h: ÷ 10. To m/h: ÷ 1,000.

Cave formation rates (stalactite/stalagmite growth), extremely slow material creep, and long-term geological monitoring.

Stalactite growth: 0.1–1 mm/h in active caves. Human hair growth: ~0.015 mm/h. Fingernail growth: ~0.004 mm/h.

Using for anything except the slowest processes. Confusing with mm/min (60× faster).

1,000 mm/h = 1 m/h. Extremely specialized unit. Think geological time scales.

Mile per second measures statute miles traveled in one second. An extremely high speed unit used for spacecraft, missiles, and astronomical phenomena.

1 mi/s = 60 mi/min = 3,600 mph = 1,609.344 m/s = 5,793 km/h.

To mph: × 3,600. To km/h: × 5,793. To m/s: × 1,609.344.

Earth's orbital speed: 18.5 mi/s. Moon's orbital speed: 0.64 mi/s. Space shuttle orbital: 4.9 mi/s. Escape velocity: 6.95 mi/s.

Earth escape velocity: 6.95 mi/s (11.2 km/s). Solar escape (from Earth): 26 mi/s. Fastest spacecraft (Parker Solar Probe): 120 mi/s peak.

Underestimating how fast this is — 1 mi/s is 3,600 mph, incredibly fast. Confusing with mi/min (60× slower).

Think 'space speeds in miles.' 1 mi/s ≈ 1.6 km/s. To escape Earth: ~7 mi/s. Orbital speed: ~5 mi/s.