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,
The Man from Planet X The Man from Planet X The Man from Planet X is a 1951 independently made American black-and-white science fiction horror film, produced by Jack Pollexfen and Aubrey Wisberg, directed by Edgar G. Ulmer, that stars Robert Clarke, Margaret Field, and William Schallert. The film was distributed by United Artists. A scientist is monitoring a mysterious "Planet X" that has entered our solar system and is now near the Earth. A spaceship from the planet lands, and a space-suited humanoid emerges who speaks in musical tones. The alien makes contact with a small pocket of humanity in an isolated, fog-shrouded Scottish