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Mantle convection occurs at rates of centimeters per year, and it takes on the order of hundreds of millions of years to complete a cycle of convection. Neutrino flux measurements from the Earth's core (see kamLAND) show the source of about two-thirds of the heat in the inner core is the radioactive decay of 40 K, uranium and thorium.
Size comparison of the Sun, all the ... gravitational or magnetohydrodynamic waves are produced by turbulence in the convection ... Within 10 light-years of the Sun ...
Atmospheric convection is the result of a parcel-environment instability (temperature difference layer) in the atmosphere. [ jargon ] Different lapse rates within dry and moist air masses lead to instability.
The Earth's atmospheric circulation varies from year to year, but the large-scale structure of its circulation remains fairly constant. The smaller-scale weather systems – mid-latitude depressions , or tropical convective cells – occur chaotically, and long-range weather predictions of those cannot be made beyond ten days in practice, or a ...
On a global scale, surface expression of this convection is the tectonic plate motions and therefore has speeds of a few cm per year. [ 15 ] [ 16 ] [ 17 ] Speeds can be faster for small-scale convection occurring in low viscosity regions beneath the lithosphere, and slower in the lowermost mantle where viscosities are larger.
Another form of convection is forced convection. In this case, the fluid is forced to flow by using a pump, fan, or other mechanical means. Convective heat transfer , or simply, convection, is the transfer of heat from one place to another by the movement of fluids , a process that is essentially the transfer of heat via mass transfer .
In solar physics and observation, granules are convection cells in the Sun's photosphere. They are caused by currents of plasma in the Sun's convective zone, directly below the photosphere. The grainy appearance of the photosphere is produced by the tops of these convective cells; this pattern is referred to as granulation.
Solar cycles last typically about eleven years, varying from just under 10 to just over 12 years. Over the solar cycle, sunspot populations increase quickly and then decrease more slowly. The point of highest sunspot activity during a cycle is known as solar maximum, and the point of lowest activity as solar minimum.