Last week Mars, now the Moon. This is going to turn theories of the solar system upside down. But when you think about it, if Earth got all its water from comets then it stands to reason that the comets which collided with all the other solar system bodies would have also contained water. And now that we have been made aware that many famous comets such as Halley and Hale Bopp are interlopers from other stellar systems, it is pretty certain that most planetary systems must contain copious amounts of water too. This bodes well for the existence of life elsewhere in the nearby galaxy because the Sun was formed within a cluster of hundreds of stars. Many of these stars are well known objects in the night sky and include Sirius and most of the stars in the Plough.