the solar system

This is the earth, right now. It's 12,742 km across. You are down here, say hi!

Scroll down, and keep going.

the moon

A quarter of the width of the earth, and always the same face turned towards us. It is away, and its light takes to reach us. All the other planets would fit in the gap, side by side.

the sun

1.39 million km across: 109 earths, side by side. It is away, so the light we see left it ago.

the inner planets

mercury, venus, the earth and mars: the four rocky planets, huddled close to the sun. mars, half the width of the earth, is from us today: a message sent there takes .

the asteroid belt

Hundreds of thousands of rocks between mars and jupiter. All of them together weigh less than our moon, and it is so empty that spacecraft cross it without trying to dodge anything.

jupiter

Twice as heavy as all the other planets put together, with a storm on it wider than the earth that has blown for two hundred years. Two swarms of asteroids share its orbit, sixty degrees ahead of it and behind: the greeks and the trojans.

saturn

Its rings are 270,000 km across and, in most places, about ten metres thick: ice, from grains of dust to boulders the size of a house.

the ice giants

uranus, rolling on its side, and neptune, away. Out there, the sun is nine hundred times dimmer.

the kuiper belt

Past neptune, a ring of ice worlds left over from when the planets formed. pluto is one of them; it takes 248 years to go round the sun once.

voyager 1

Launched in 1977, it is now away: the farthest thing anyone has ever made. In 2012 it crossed the heliopause, where the wind from the sun gives out. Its messages take to get home.

the oort cloud

Perhaps a trillion comets, reaching a good part of the way to the next star. Nobody has ever seen it: we only know it from the comets it sends us.

alpha centauri

The nearest star, 4.37 light-years away. The light you would see from it tonight left in .

And from here, the sun is just one more star.

The sizes and the distances are true; only the planets drawn as dots are bigger than they should be, or you would not see them at all. The stars behind come from the night sky.

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