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,
Natural gas pipeline system in the United States Natural gas pipeline system in the United States The US natural gas pipeline system is a complex system of pipelines that carries natural gas nationwide and for import and export for use by millions of people daily for their consumer and commercial needs. Across the country, there are more than 210 pipeline systems that total more than 305,000 miles of interstate and intrastate pipelines. Of the lower 48 US states, those with the most natural gas pipeline running through them are Texas (58,588 miles), Louisiana (18,900), Oklahoma (18,539), Kansas (15,386), Illinois (11,900) and California (11,770). The states with the least