Search results
Results from the WOW.Com Content Network
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 .
In solar physics and observation, supergranulation is a pattern of convection cells in the Sun's photosphere. The individual convection cells are typically referred to as supergranules . The pattern was discovered in the 1950s by A.B. Hart [ 1 ] using Doppler velocity measurements showing horizontal flows on the photosphere (flow speed about ...
The core of the Sun is considered to extend from the center to about 0.2 of the solar radius (139,000 km; 86,000 mi). [1] It is the hottest part of the Sun and of the Solar System. It has a density of 150,000 kg/m 3 (150 g/cm 3) at the center, and a temperature of 15 million kelvins (15 million degrees Celsius; 27 million degrees Fahrenheit). [2]
On July 11, NASA's Solar Dynamics Observatory captured a big hole on the surface of the sun. Tom Yulsman who writes for Discover's ImaGeo blog notes that there is no reason for people to be concerned.
The Sun's atmosphere is composed of five layers: the photosphere, the chromosphere, the transition region, the corona, and the heliosphere. The coolest layer of the Sun is a temperature minimum region extending to about 500 km above the photosphere, and has a temperature of about 4,100 K. [77]
In thick solar cells there is very little electric field in the active region outside the space charge zone, so the dominant mode of charge carrier separation is diffusion. In these cells the diffusion length of minority carriers (the length that photo-generated carriers can travel before they recombine) must be large compared to the cell ...
Below, gravity tends to dominate the shape of most features, so that the Sun may often be described in terms of layers and horizontal features (like sunspots); above, dynamic forces dominate the shape of most features, so that the transition region itself is not a well-defined layer at a particular altitude.
A coronal hole at the Sun's north pole observed in soft X-ray. Coronal hole size and population correspond with the solar cycle. As the Sun heads toward solar maximum, the coronal holes move closer and closer to the Sun's poles. [4] During solar maxima, the number of coronal holes decreases until the magnetic fields on the Sun reverse.