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,
Sustain Our Planet analysis and a list of recommendations on how a business might reduce its carbon footprint over time. Sustain Our Planet's Green Schools Program is an online teaching resource for children and educators interested in learning and practicing techniques that help protect the planet. This downloadable teaching resource contains green lesson plans, environmentally themed experiments, and green classroom activities on the carbon cycle, saving energy, recycling, and endangered animals. All content compliments the National Standards set by the US Department of Education for Science, English and Art. Sustain Our Planet Sustain Our Planet is a consulting firm that provides carbon calculation