# Travel times across the Solar System

> How long a journey between two worlds would take, how far apart they are right now, and how long a radio signal needs. Computed for a moment you choose.

Canonical: https://spacesphere.sygnito.com/en/solar/travel

## Travel times

Pick a starting point and a destination. Every figure below says where it comes from.

## In a straight line, at a steady speed

Journey time = distance divided by speed

This is arithmetic, not a journey. Nobody could travel this way: there is no straight road, nothing can hold these speeds the whole way, and the destination does not wait where it is now.

The destination is moving. By the time you arrived it would be somewhere else, which is why a real mission aims at where it will be.

## For real: the cheapest possible flight

It is a range, not a single figure, because how long the trip takes depends on when you launch.

This assumes both orbits are perfect circles in one plane. They are not, which is why the answer is a range.

A launch window is a season a few weeks wide, not a single day.

The flight time and launch window are shown for journeys starting from Earth.

## Labels on every figure

- A speed we chose
- Published value
- Computed now
- Our calculation
- Computed for this date
- Found from real positions

Outside the Solar System. Straight line arithmetic only, and the distance is a fixed published figure rather than a live one, so it does not change with the date.

Distances and signal times are computed for the moment you choose, so this markdown version lists none of them.

## Sources

- Distance: [ESA/Gaia/DPAC](https://www.cosmos.esa.int/gaia), Gaia DR3 (parallax 768.0665 mas).

## Related

- [Solar System](https://spacesphere.sygnito.com/en/solar)