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).
The atmosphere is a thin blanket of gases that surrounds the Earth. The Earth's atmosphere comprises nitrogen, oxygen and various trace gases. There are four layers in the atmosphere, each of a different temperature: troposphere, stratosphere, mesosphere and thermosphere. Definition of atmospheric pressure. Atmospheric pressure is the force exerted over the Earth resulting from gravity pulling down on the molecules in the air. The unit of measurement is inches of mercury, or inHg. Atmospheric pressure determines the weather, which occurs in the troposphere.