The reason is that darknessâor, to put it the other way, the absence of lightâstimulates the production of a hormone, melatonin, from its immediate precursor, the neurotransmitter serotonin. Like serotonin, melatonin plays important roles in our physical and mental well-being.
The five major ocean gyres. A gyre in oceanography is any large system of circulating ocean currents, particularly those involved with large wind movements. Gyres are caused by the Coriolis effect; planetary vorticity along with horizontal and vertical friction, determine the circulation patterns from the wind curl (torque).
Definition of TROPOSPHERE. : the lowest densest part of the earth's atmosphere in which most weather changes occur and temperature generally decreases rapidly with altitude and which extends from the earth's surface to the bottom of the stratosphere.â troÂ·poÂ·spherÂ·ic \ËtrÅ-pÉ-Ësfir-ik, Ëtrae-, -ËtrÃ¤-\ Ësfer. adjective the lowest densest part of the earth's atmosphere in which most weather changes occur and temperature generally decreases rapidly with altitude and which extends from the earth's surface to the bottom of the stratosphere. â troÂ·poÂ·spherÂ·ic \ËtrÅ-pÉ-Ësfir-ik, Ëtrae-, -ËtrÃ¤-\ Ësfer. adjective