Sunny countries are often poor. It is a shame, then, that solar power is still quite expensive. But it is getting cheaper by the day, and is now cheap enough to be competitive with other forms of energy in places that are not attached to electricity grids. Since 1,6bn people are still in that unfortunate position

Towards the end of the Gulf war in 1991, an American armoured scout unit in Iraq’s southern desert stumbled upon a much larger elite force of dug-in Iraqi armour. Rather than retreating, the nine American tanks and 12 Bradley fighting vehicles attacked. When the battle ended about 25 minutes later, the Americans

Imagine yourself with a thousand small crates that must be moved from A to B along roadways. Inside each is part of an intricate construction that cannot be complete until every piece has arrived. You have options. One is an oversized lorry that may pass only along the largest motorways, but can carry all

“Ideas are like rabbits,” said John Steinbeck. “You get a couple and learn how to handle them, and pretty soon you have a dozen.” The same could be said of ideas fora, whose population expanded again in February with the birth of Solve For X, an experimental Google-sponsored conference where entrepreneurs