Solar Terrestrial Planets
Earth's 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 they have all merged with, or been ejected by, the four remaining worlds in the solar nebula.
Dwarf planets, like Ceres and Pluto, and other large asteroids 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 and Pluto have a density of 2.1 g cm−3, and Haumea's density is similar to Pallas's 2.8 g cm−3).
Read more about this topic: Terrestrial Planet
Famous quotes containing the words solar and/or planets:
“Senta: These boats, sir, what are they for?
Hamar: They are solar boats for Pharaoh to use after his death. They’re the means by which Pharaoh will journey across the skies with the sun, with the god Horus. Each day they will sail from east to west, and each night Pharaoh will return to the east by the river which runs underneath the earth.”
—William Faulkner (1897–1962)
“I would sell my life to avoid
the pain that begins in the crib
with its bars or perhaps
with your first breath
when the planets drill
your future into you....”
—Anne Sexton (1928–1974)