This morning, American space experts will attempt to make a crucial discovery about the moon by chucking several tons of metal at it. It does not sound very scientific, but NASA is hoping the cloud of dust that will be thrown up by the impact will reveal what is deeper below the surface than they have ever been able to find before, and which may confirm the presence of water.If there’s water on the moon, it will change the game for space exploration. “This experiment, LCROSS, is designed to excavate four to ten metres deep into that soil with enough energy, a copule of tons of TNT equivalent, from that whack of the empty upper centaur stage to probe deeper into the moon and to produce a signature, a signal that we can measure,” says the project’s lead scientist. Water could provide oxygen to breathe, and hydrogen to use as fuel, among other things: “One of the great things about eventual human exploration of the moon or anywhere is the idea that we might be able to live off the land. Use what it offers, rather than bringing it all with us.” The impact will produce a crater within a crater about half the size of an Olympic swimming pool. You can follow LCROSS’s expoits live, as it has its own Twitter feed.