Cosmic Velocity - Third to Millimeter per Second

The third cosmic velocity is approximately 16,700 m/s (16.7 km/s), the minimum speed to escape the Sun's gravity from Earth's orbital position.

v₃ = √(v_sun² - v_Earth²) where v_sun is solar escape velocity from Earth's orbit. Approximately 16.7 km/s relative to Earth.

To km/h: × 3,600. To mph: × 37,282. 16.7 km/s = 60,120 km/h = 37,344 mph.

Voyager missions, future interstellar probes, and calculations for leaving the solar system.

Voyager 1: ~17 km/s relative to Sun (achieved via Jupiter gravity assist). Parker Solar Probe: 163 km/s peak (but toward Sun, not away).

Thinking Voyager was launched at 16.7 km/s — it used gravity assists. Also, confusing with speed needed to escape from Sun's surface (618 km/s).

~17 km/s to leave the solar system from Earth's orbit. Voyagers achieved this with gravity assists from planets.

Millimeter per second measures distance in millimeters traveled in one second. Used for small-scale movements and precise measurements.

1 mm/s = 0.001 m/s = 0.0036 km/h = 0.06 m/min.

To m/s: ÷ 1,000. To cm/s: ÷ 10. To km/h: × 0.0036.

Vibration measurements (machinery typically 0.1–50 mm/s RMS), small motor speeds, precision linear actuators, and tape/film transport speeds.

Machinery vibration: >10 mm/s indicates problems. Seismic activity: 0.001–100 mm/s. CD/DVD read head: 1.2–1.4 mm/s linear velocity.

Confusing mm/s with cm/s (10× different) or m/s (1000× different).

1,000 mm/s = 1 m/s. Very common in vibration analysis. 10 mm/s RMS is a typical machinery vibration threshold.