Jupiter Moons - Callisto discovered by Galileo Galilei in 1610 using a telescope. It is thought to have oceans of liquid water beneath its crust. about the size of Mercury, is the 3rd largest moon in the solar system. It is more heavily cratered than any other moon in the solar system. Callisto remains as it was when it formed, during the period of intense meteoroid bombardment that the entire solar system experienced
The world's first Active House stands at the crest of an estate. Its south-facing roof is covered in solar panels and solar cells, which between them harness more than enough power to keep the occupants warm and the appliances running. In around 30 years' time, if designers have got their sums right, the excess electricity flowing from the house into Denmark's grid will have cancelled out the energy costs of building it, leaving a non-existent footprint on the earth's resources.