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,
A Beautiful Planet twisted, inverted; you can completely lose your spatial awareness about where you are and what your attitude is, and you can easily get tangled up in that safety tether if you're not cautious. Every single movement you make, you're making an effort to think [things] through." After spending almost the entire film scrutinizing the Earth and the ISS (with its astronauts) in low Earth orbit, one of the final scenes of "A Beautiful Planet" briefly examines an important extrasolar planet (a planet outside of our solar system) which was discovered in 2014. The planet, Kepler-186f, was the first approximately-Earth-sized planet