Sun, Earth & Moon to Scale
betaSee the real sizes, distances and spins of the Sun, Earth and Moon — zoom from the whole orbit down to a single turning globe
How it works
The main view looks down on the plane of Earth's orbit with every size and distance in true proportion, positioned for the date you choose. Because space is almost entirely empty, that is humbling: with the whole orbit in view the Sun is two pixels wide and Earth a fiftieth of a pixel, so rings mark what is too small to draw, and you can zoom in more than a million times — to the Earth–Moon pair, then to one body filling the screen. A Schematic switch gives the familiar textbook picture with sizes enlarged. Three magnified close-ups always show the rotations: the Sun turning in about 25 days, the Earth (with real coastlines, seen from above the pole) once every 23 h 56 min, and the Moon once per orbit so the same face stays toward Earth. Play time at up to thirty days a second or scrub the day and hour. Below are the three bodies drawn to scale side by side, the Earth–Moon gap to scale with light crossing it at its true speed, a scale-model calculator, and a table of sizes, spins, speeds and live distances. Positions come from the astronomy-engine library; everything runs in your browser.
Questions
How big is the Sun compared with the Earth and Moon?
The Sun is about 1.39 million km wide — 109 Earths across, with room for roughly 1.3 million Earths inside. The Moon is 3,475 km wide, 27% of Earth's width.
How far apart are they, in those terms?
The Moon is about 384,400 km away, roughly 30 Earth-widths; all the other planets would fit in the gap. The Sun is about 149.6 million km away — 107 Sun-widths, or nearly 12,000 Earth-widths, and about 390 times farther than the Moon.
If the Sun were a 1 m ball, how big and far is Earth?
Earth would be a 9 mm bead 107 m away, and the Moon a 2.5 mm grain 28 cm from the Earth. Light would crawl at about 22 cm per second. The calculator works for any size, starting from any of the three.
Does the Moon rotate?
Yes — once every 27.3 days, exactly the time it takes to orbit the Earth. That tidal locking is why we always see the same face. The close-up shows the dark patches of the near side staying pointed at Earth.
Why is a day 24 hours if Earth turns in 23 h 56 min?
Earth turns once relative to the stars in 23 h 56 min, but in that time it has moved about 1° along its orbit, so it needs roughly four more minutes of turning for the Sun to return to the same place in the sky.
Why do the Sun and Moon look the same size?
A coincidence of this era: the Sun is about 400 times wider than the Moon and about 400 times farther away, so both span roughly half a degree — which makes total solar eclipses possible.