How Far Away Is the Moon?

Step 1 of 5

Space pictures lie about distance.

Every diagram squeezes the Moon close to Earth so both fit on the page. The real gap is about thirty Earths wide.

Step 2 of 5

The real number is 384,400 km.

That is roughly ten trips around the equator. If you could drive there at motorway speed without stopping, it would take about five months.

Step 3 of 5

Even light takes over a second.

Light is the fastest thing there is, and it still needs 1.3 seconds each way. Radio calls to Apollo astronauts had a noticeable delay.

Step 4 of 5

Apollo took three days.

The fastest crewed spacecraft ever built still needed about 73 hours of travel to cross that gap.

Step 5 of 5

And the gap is growing.

Tides slowly transfer energy from Earth's spin to the Moon's orbit, pushing it about 3.8 cm further away every year.

Laser reflectors left by Apollo astronauts are how we measure the distance to within a few centimetres.