How long would it take to reach another planet?
Pick a destination — Mercury out to Neptune — and a travel speed, then send a little ship on its way. As it crosses the star field the journey plays out, and only when it reaches the planet does the travel time appear, so you experience the trip before you see the number. Distances are average Earth-to-planet gaps; because orbits are elliptical, the real distance shifts all the time.
From a walk to the speed of light
The speeds run from the everyday to the interstellar: walking, a car, a plane, the International Space Station, the Voyager probe, and a slider for a chosen fraction of light speed. Space is so vast that even the fastest options give staggering answers — reaching Neptune at Voyager's speed takes thousands of years — which is exactly what makes it fun to explore.
Just for wonder
This is a back-of-the-envelope tool: it assumes a constant speed and ignores acceleration, gravity and the fact that planets keep moving along their orbits. Use it to get a feel for the scale of the solar system, not to plan an actual mission.
Frequently asked questions
How are the distances chosen?
They're the average distance between Earth and each planet. Real distances vary constantly as both planets orbit the Sun, so treat them as ballpark figures.
Why does the time only show at the end?
So you experience the journey first — the ship travels, then the arrival reveals how long the trip would really take.
How long does it take to travel between planets?
It depends on the planets' positions and the spacecraft's speed. A trip to Mars typically takes about 7–9 months with current technology.
Why does travel time to a planet vary so much?
Because planets move. The distance between Earth and Mars, for example, changes constantly as both orbit the Sun, so launch windows matter a lot.
How fast do spacecraft travel?
Robotic probes reach tens of thousands of km/h. Even so, the vast distances mean journeys across the solar system take months or years.