Stability of the Solar System essentially the distance from sun to earth). These are now known as the Kirkwood gaps. Some asteroids were later discovered to orbit in these gaps, but their orbits are unstable and they will eventually break out of the resonance due to close encounters with a major planet. Another common form of resonance in the Solar System is spin–orbit resonance, where the period of spin (the time it takes the planet or moon to rotate once about its axis) has a simple numerical relationship with its orbital period. An example is our own Moon, which is in a 1:1 spin–orbit resonance
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 The ban on electric hot water systems was repealed on