Solar System 7 light-years away. Compared to many other planetary systems, the Solar System stands out in lacking planets interior to the orbit of Mercury. The known Solar System also lacks super-Earths (Planet Nine could be a super-Earth beyond the known Solar System). Uncommonly, it has only small rocky planets and large gas giants; elsewhere planets of intermediate size are typical—both rocky and gas—so there is no "gap" as seen between the size of Earth and of Neptune (with a radius 3.8 times as large). Also, these super-Earths have closer orbits than Mercury. This led to hypothesis that all planetary systems start
Solar hot water in Australia exported. Four of the original companies are still in business and the manufacturing base has now expanded to 24 companies. Water heating is the largest single source of greenhouse gas emissions from the average Australian home, accounting for around 28 per cent of home energy use (excluding the family car). The Australian government estimates that installing a climate friendly solar powered hot water system can save a family $300 to $700 off electricity bills each year. The solar hot water rebate program for financial year 2009 offered a $1600 rebate for the installation of solar powered hot water systems. The