Formation and evolution of the Solar System depletion period that brought the asteroid belt down close to its present mass is thought to have followed when Jupiter and Saturn entered a temporary 2:1 orbital resonance (see below). The inner Solar System's period of giant impacts probably played a role in the Earth acquiring its current water content (~6 kg) from the early asteroid belt. Water is too volatile to have been present at Earth's formation and must have been subsequently delivered from outer, colder parts of the Solar System. The water was probably delivered by planetary embryos and small planetesimals thrown out of the asteroid belt by
Solar hot water in Australia rebates are offered at the present, however the Queensland government in 2007 announced the phasing-out of electric hot water systems commencing in 2010. From 2010, Queenslanders who need to replace their household hot water system due to breakdown will no longer be able to install electric systems, and will instead have to choose from gas, solar or heat pump options. Prior to this, the Queensland government had already banned the installation of electric hot water systems in newly constructed houses; a law which came into effect on 1 March 2006. The ban on electric hot water systems was repealed on