The most spectacular feature of the Sun’s surface is the ‘Sunspots’. Galileo was the first man to observe these spots in 1610 with the help of his telescope. Through the telescope the Sunspots looked like dark holes on the shining surface of the Sun.
These spots often appear in groups. They increase in number, and then diminish in regular cycles. These cycles repeat every seventh, eleventh or fourteenth year. The portion of the Sun having these spots emits light of less intensity. According to modern scientific theories, these spots are formed by reactions between the electrically charged gases of the Sun and solar magnetic fields. When at any place on the Sun, strong magnetic field develops; the temperature of that place is lowered. Consequently, these portions appear as black spots amidst hotter and brighter portions. The temperature of these spots is approximately 4000° C. They are not permanent but go on changing.
Can you imagine the size of these spots? Some spots are big enough to accommodate hundreds of earths. Even a small spot is so big that it can cover two-thousandth part of the Sun’s surface. These spots are spread over an area of 500 million square miles on the Sun. On June 4, 1946 scientists saw a Sunspot measuring 4, 80,000 km in length and 1, 12,000 km in breadth. Most of the solar spots last for a few days only. But some may last for two months or even more.
It is inferred from the change of state of Sunspots that, like the earth, the Sun is also rotating on its own axis. These spots are moving from East to West because the Sun is moving from East to West. Changes occur in the location, sizes and rotation period of these spots.
