Terrestrial planet from the original solar nebula. The Solar System has four terrestrial planets: Mercury, Venus, Earth, and Mars. Only one terrestrial planet, Earth, is known to have an active hydrosphere. During the formation of the Solar System, there were probably many more terrestrial planetesimals, but most merged with or were ejected by the four terrestrial planets. Dwarf planets, such as Ceres, Pluto and Eris, and small Solar System bodies are similar to terrestrial planets in the fact that they do have a solid surface, but are, on average, composed of more icy materials (Ceres, Pluto and Eris have densities of 2.17,
Solar hot water in Australia from 01/10 2007 to 30/06 2009, offered all house owners in NSW a rebate on systems that were replacing existing electric hot water systems. The more efficient the system (emitting less Greenhouse gas), the more RECs the system was eligible for, generating a higher rebate. Power and Water Corporation, the principal water and electricity supplier in the Northern Territory, offers an REC buyback scheme on installations of solar water heaters. The buyback must be applied for and assigned less than one year after the installation. The Queensland Government's Solar hot water rebate scheme finished on 30 June 2005. No state