Terrestrial planet Terrestrial planet A terrestrial planet, telluric planet, or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun, i.e. Mercury, Venus, Earth, and Mars. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth ("Terra" and "Tellus"), as these planets are, in terms of structure, "Earth-like". Terrestrial planets have a solid planetary surface, making them substantially different from the larger giant planets, which are composed mostly of some combination of hydrogen, helium, and water existing in various
Hidden states of matter exists in equilibrium, but is not immediately apparent or easily observed. Using ultrashort laser pulses impinging on solid state matter, the system may be knocked out of equilibrium so that not only are the individual subsystems out of equilibrium with each other but also internally. Under such conditions, new states of matter may be created which are not otherwise reachable under equilibrium, ergodic system evolution. Such states are usually unstable and decay very rapidly, typically in nanoseconds or less. The difficulty is in distinguishing a genuine hidden state from one which is simply out of thermal equilibrium. Probably the first