STRUCTURE OF THE SUN

The Sun has an atmosphere which can be divided into three layers :-

• the corona
• the chromosphere 
• the photosphere

The corona is the outermost layer of the Sun's atmosphere. It is actually a layer of gas boiled off from the Sun. The corona extends for thousands kilometres into outer space. It is the hottest layer of gas in the Sun's at atmosphere, with a temperature of about 1 500 000 degree Celsius. The corona is a faint whitish blue region and can only be seen during an eclipse of the Sun. The corona gives out X-rays.

The chromosphere is a layer of gas below the corona. 'Chromosphere' means a sphere of colour, so called because  of its reddish-pink colour. This layer of gas is about 5 000 km thick. Its temperature can rise as high as 50 000 degree Celsius. It can only be seen during an eclipse of the Sun because it is not bright.

The photosphere is a layer of heavy gas which can be seen from Earth as a bright lighted surface. 'Photosphere' means a sphere of light. The photosphere has a temperature of about 6 000 degree Celsius. Its surface appears very rough because the gases from core bubble throught it. Solar flares, prominences and sunspot erupt from its surface.

If the size of the Sun is represent by a coconut shell, the the size of the Earth may be represent by a green pea.