You'll have picked up our maths lessons, of course - the sequences of prime numbers we beam into the universe to show how clever we are. And maybe you'll have already puzzled over some episodes of 'I Love Lucy' that leaked into space when we invented television.
But what you see now as you approach our planet for the first time is a pattern we make quite unconsciously - the pattern of lights with which we paint the night.
Set your keenest code-crackers to work on these glints and glimmers, for they will teach you more about us than anything you might see from space by day, except, perhaps, our Millennium Dome.
Need some clues to get you started? Well, the vivid yellow lights shine from our great cities. But bear in mind that we also live amid the inky voids - a slower, dimmer life that is not driven by electricity. This division of light and shade tells you most about us.
There is red light in the pattern, and splashes of violet, and each of these betrays a wasteful streak in our nature. For here you catch us using fire to burn off natural gas and to rid our land of unwanted forest.
We can take no credit for those delicate blue wisps we call the Northern Lights. But the lurid green, close to the string of islands that shines so fiercely in the east - that's us, demonstrating our great fondness for a fellow species called the squid.
Oh, and one last disappointment before you land. Lucy doesn't live here any more.