Plan interstellar journeys — calculate travel times, time dilation effects, energy requirements, and compare speeds for exoplanet destinations.
Interstellar travel remains one of humanity's greatest aspirations and challenges. Even the nearest star system, Proxima Centauri at 4.24 light-years away, would take over 73,000 years to reach at Voyager 1's speed. At a fraction of the speed of light, however, relativistic effects become significant—time passes more slowly for travelers than for people back on Earth.
This exoplanet travel planner calculates journey times from both the Earth frame and ship frame perspectives, accounting for special relativistic time dilation. It estimates the kinetic energy needed to accelerate your spacecraft, the number of human generations that would pass aboard a generation ship, and how signal communication delays would grow with distance.
Choose from famous exoplanet destinations like Proxima Centauri b, the TRAPPIST-1 system, and Kepler-442b, then experiment with different travel speeds from current spacecraft capabilities to substantial fractions of the speed of light. The comparison tables reveal just how dramatically speed affects feasibility.
This calculator makes the mind-bending physics of interstellar travel accessible and tangible. By comparing real spacecraft speeds with relativistic velocities, you gain an intuitive understanding of both the immense challenge and the fascinating physics that would make such journeys possible. The note above highlights common interpretation risks for this workflow. Use this guidance when comparing outputs across similar calculators. Keep this check aligned with your reporting standard.
Earth-frame travel time: t_earth = d / v. Ship-frame travel time: t_ship = t_earth / γ where γ = 1/√(1 − v²/c²). Relativistic kinetic energy: KE = mc²(γ − 1). Generations: t_ship / 25 years.
Result: Earth time: 42.4 years; Ship time: 42.2 years
At 10% the speed of light, Proxima Centauri b takes 42.4 Earth-years. Time dilation is minimal at 0.1c (γ ≈ 1.005), so crew experience nearly the same duration.
Use consistent units, verify assumptions, and document conversion standards for repeatable outcomes.
Most mistakes come from mixed standards, rounding too early, or misread labels. Recheck final values before use. ## Practical Notes
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Track units and conversion paths before applying the result. ## Practical Notes
Use this note as a quick practical validation checkpoint. ## Practical Notes
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Use as a sanity check against edge-case outputs. ## Practical Notes
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Proxima Centauri b orbits at 4.24 light-years from Earth, making it the closest known exoplanet.
A hypothetical interstellar spacecraft that would travel so slowly that multiple human generations would live and die aboard during the journey. Use the examples and notes as a quick consistency check before trusting any value.
Time dilation effects become noticeable above about 10% of light speed and dramatic above 50%. At 0.99c, γ ≈ 7.09, meaning 7 years pass on Earth for each year on the ship.
Enormous amounts. Accelerating a 1,000-ton ship to 10% light speed requires roughly the energy output of the entire world for several years.
With current technology, no practical mission exists. Concepts like Breakthrough Starshot propose sending tiny probes at 20% light speed using laser sails, potentially reaching Proxima Centauri in about 20 years.
The speed of light in vacuum is 299,792.458 km/s or about 186,282 miles per second. It is the ultimate speed limit in the universe.