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
Gas–liquid contactor is higher for equipment with higher values of gas–liquid interface surface area, so gas–liquid contactors with high surface area (e.g. packed column, spray tower) are often preferred when it is important to lower the cost of the equipment. Liquid hold-up is also an important factor for the economy of the process, because for low values of liquid hold-up a bigger equipment is needed to have the same heat and mass transfer velocity. For this reason, gas–liquid contactors with low liquid-hold-up (e.g. falling-film column) in general are not used at industrial scale. Gas–liquid contactor A gas–liquid contactor is a particular chemical