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 greenhouse gas and carbon emissions. In the case of Victoria, for example, converting from electric to solar hot water could save 20% of the state's total greenhouse gas emissions. Despite an excellent solar resource, the penetration of solar water heaters in the Australian domestic market is only about 4% or 5%, with new dwellings accounting for most sales. During the 1950s, Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) carried out world leading research into flat plate solar water heaters. A solar water heater manufacturing industry was subsequently established in Australia and a large proportion of the manufactured product was