Solar Surface May at www.japanese-home-gardens.com

From known values for the radius of the sun and for the earth-sun distance the radiancy at the solar surface may now be computed and, if the sun can be considered a radiating black-body, its surface temperature can be determined by means of the Stefan-Boltzmann law. Thus we find the sun's radiancy equals 62,900 kw/meter, and its surface temperature equals 5,800 kelvins. Because the moon is so close to the earth and has a negligible atmosphere we might expect the intensity of solar radiation at normal incidence on its surface to be very nearly 1,360 watts/ meter2, and therefore, if it can be considered a blackbody, its surface temperature for the sun directly overhead should equal (1,360/5.6697 x 10^ )'4 or 394 kelvins. This computed value agrees very well with the maximum observed temperature of 390 kelvins from the Surveyor series of moon-based measurements.

The rockets turned off when the Surveyor was about 10 ft (3 m) above the surface. The spacecraft was then traveling at less than 10 mph (16 km/hr) and dropped freely to the lunar surface for a gentle landing. On the surface the Surveyor extended and oriented its solar panels to generate electric power and began its various measurements.

Beyond the chromosphere is the corona, a region of tenuous gas stretching millions of kilometers above the solar disk. At any particular moment there may be as many as 100,000 spicules (jets of gas) shooting out of the chromosphere into the corona to heights of 10,000 km (6,214 mi). There are also solar flares, sudden great bursts of energy that occur most often during periods of solar activity.