Look at the earth — isn't it beautiful?
Blue oceans, white polar ice-caps, and verdant green land.
Some brown as well, where there aren't as many plants.
But why are those parts of our earth barren, and others green?
I mean, deserts cover much of Africa and Australia, but not Europe!
Europeans, it turns out, discovered the answer, but in the most unlikely of places – the oceans!
When sailing from Europe, trade winds pushed ships enthusiastically southwest to the equator, where suddenly, the winds would die.
These were the doldrums.
And for sailors, they were a pain.
They were also annoying to scientists like Galileo, Kepler, and Halley, who all had theories about why the wind blew to the southwest: Did the wind somehow follow the sun from morning till night?