THE SUN’S ATMOSPHERE
The suns
atmosphere consists of three layers. The lowest is the photosphere, a thin
layer only 500 km thick that emits most of the suns light and that has a
density of 10 23/m 3 .Above it lies the rare and more
transperant chromospheres with a density of 10 17/m 3 ,and the corona with a density typically of 10
15/m 3 near the
sun extending out of the earth orbit and beyond. The temperature falls to a
minimum value of 4200K in the photosphere. The effective temperature of the sun
is 5785K.
Progressing outward into the suns
atmosphere, the temperature rises slowly to the chromosphere, and then at an
altitude if 2 or 3 Mm, it suddenly increases to 2*10 6 k or so in the corona. This was
discovered only in 1940.But that high temperature is somewhat deceptive, if
ones hand were immersed in a bottle of coronal gas, its temperature would rise
by only a fraction of a degree, because the low density of corona means that it
contains only a minute amount of heat!!!
There is a general magnetic field
on the sun with a strength of about 1 or 2 gauss. The sun is the source of
energy in the solar system and maintains life on this planet. Sun produces this
energy by thermonuclear reactions taking place in the suns interior.
No comments:
Post a Comment