MPH · USA UNITS · RELATIVITY
How long to get there?
Pick a destination and a speed Americans actually recognize — highway mph, Shuttle mph, or a slice of light speed. See Earth time vs ship time (time dilation).
Travel Analysis —
Distance
Speed
Earth Time
Ship Time (you age)
Lorentz Factor (γ)
Time You Save vs Earth
Relativistic Effect
What You Would Experience
Destination notes
Moon — 238,855 miles
0.00257 AU · 1.28 light seconds
Apollo 11 took about 76 hours at ~24,200 mph. The Moon drifts away ~1.5 inches per year. SpaceX Starship is aiming for crewed lunar landings this decade.
Mars — 34M to 250M miles
0.36–2.67 AU · 3 to 22 light minutes
Distance swings a lot. Perseverance took about 7 months. NASA and SpaceX are racing toward crewed Mars windows in the 2030s.
Proxima Centauri — 4.24 light years
~25 trillion miles
Nearest star system. Breakthrough Starshot dreams of ~20% light speed nanosails. At New Horizons speed: tens of thousands of years.
Andromeda — 2.537 million light years
Our nearest big galaxy neighbor
Even at light speed you need 2.5 million years. In ~4.5 billion years the Milky Way and Andromeda merge — our Sun may survive the dance.