Solar system · the Moon

The Moon in 3D: where it is and how it moves

The Moon in front of the Earth, drawn from its maps in Exo-View

The Moon is the one other world people have stood on, and it goes round the Earth once every 27 days at an average of 384,400 km. Exo-View puts it where it is at this moment, circling the Earth at the scale of the real orbit, and lets you fly out to it.

Fly to the Moon Watch the 2027 eclipse

Distance: 384,400 km on average: 356,500 km at its nearest, 406,700 km at its farthest
Orbit: 27.3 days round the Earth; 29.5 days from one new Moon to the next
Width: 3,475 km, about a quarter of the Earth's
Light from it: Takes 1.3 seconds to reach us
Gravity: About one sixth of Earth's
Temperature: From about 127 °C in sunlight to about −173 °C in the dark
Walked on by: Twelve people, from 1969 to 1972

Why we always see the same face

The Moon turns once on its axis in exactly the time it takes to go once round the Earth, 27.3 days, so the same side always faces us. The far side, which we never see from Earth, has a thicker crust and far fewer dark plains. It is not dark, only unseen: it has as much sunshine as the near side.

Phases, and why not every month has an eclipse

The phases are the Moon going round the Earth while the Sun lights half of it: new when it is between us and the Sun, full when we are between them. That takes 29.5 days, two days longer than the orbit itself, because the Earth moves on round the Sun meanwhile.

If the Moon's orbit lay in the same plane as the Earth's, every new Moon would eclipse the Sun and every full Moon would be eclipsed. Its orbit is tilted by about 5°, so the shadows usually pass above or below, and eclipses only come when a new or full Moon falls at the place where the two planes cross.

Where it came from, and where it is going

Most astronomers think the Moon formed about 4.5 billion years ago, when a planet about the size of Mars hit the young Earth and the debris gathered into a ball. It is moving away from us by about 3.8 cm a year, and it was much closer once: the day was shorter, and the Moon filled more of the sky.

In Exo-View

The key below flies to the Moon with the Earth beside it, at the real scale of the gap between them. Run the clock forward to watch it go round, or watch the total solar eclipse of 2 August 2027 in the simulation, where the Moon's shadow crosses Spain, Egypt and Arabia.