Convert Mach 20 to Speed of Light

Convert Mach 20 (Ma20) to Speed of Light (c) instantly and accurately.

Mach 20 (Ma20)
Speed of Light (c)

Conversion Formula

c = Ma20 × 2.270170519e-5

About Mach 20

Mach 20 ≈ 6,805.8 m/s (24,501 km/h) at ISA sea level - the peak heating regime of ballistic re-entry. Shock layer temperature exceeds 10,000 K; plasma sheath causes radio blackout. Space Shuttle decelerated through Mach 20 at ~75-80 km altitude; Apollo CM hit the atmosphere at ~Mach 36; ICBM warheads re-enter at Mach 18-24. DARPA HTV-2 reached Mach 20 in 2011. 1 Mach 20 = 6,805.8 m/s.

About Speed of Light

The speed of light in vacuum (c) = exactly 299,792,458 m/s - the defined SI constant from which the metre is derived (since 1983) and the universal speed limit of causality. Light from the Sun reaches Earth in 8 min 20 s; from the Moon in 1.28 s; from Proxima Centauri in 4.24 years. Mars communication delay 3-22 minutes. In optical fibre (n ≈ 1.467), c/n ≈ 200,000 km/s. GPS clocks must correct for both special and general relativistic effects. c = 299,792,458 m/s.

Quick Reference Table

Mach 20 (Ma20)Speed of Light (c)
1 Ma202.27 × 10-5 c
2 Ma204.54 × 10-5 c
5 Ma200.000113509 c
10 Ma200.000227017 c
25 Ma200.000567543 c
50 Ma200.00113509 c
100 Ma200.00227017 c

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