The Sun is the largest member of the Solar system. 99.86% of the matter of the solar system is concentrated in the Sun.
From the point of view of mass, it is 3,30,000 times that of the Earth. If seen from the point of view of volume 1,300,000 earths can be packed into the Sun. Its diameter is 109 times that of the Earth. It is 149 million km away from the Earth and light takes about 8.3 minutes to reach the Earth from the Sun. This is why the Sun looks so small. The weight of the Sun is 2 x 1027 tonnes.
The Sun is a massive and burning star. Its surface temperature is 6,000oC. The temperature of its interior is 455 million degrees of centigrade. Its brightness is 3,360 times that of a standard candle.
The Sun has great energy in it. It radiates 54-horse power from each of the square inch of its surface. This energy is produced as a result of annihilation of the matter of Sun.
In the universe, the Sun is not rated among the large stars. Many stars larger than the Sun have been known to us. The Trumpler is a star presumably 100 times larger than the Sun.
Betelgeuse is a red star and can contain 24 million Suns in it. Epsilon Aurigae is probably 2,700 million times larger than the Sun.
The Sun also rotates about its axis and being gaseous, all its parts do not rotate with the same speed. The equatorial section takes 25 days and the polar 30 days to make one rotation about its axis.
The Sun also revolves around the centre of the Milky Way in the space with a speed of 241.4 km per second. At the time of solar eclipse when the Moon covers the Sun, a bright Zone is seen around the Sun. It is known as the Corona of the Sun and the upper surface of the Sun is called as Chromosphere. It emits white light. The central part of the Sun called Photosphere.
What is possibly the cause of this tremendous emission of energy? It is known that the Sun, consisting mainly of hydrogen, continuously undergoes a change in which hydrogen changes into helium. The energy emitted during this process provides heat and light to its planets.
In ancient times, the Sun was a symbol of purity. Now, the scientists have observed black spots on its surface. It has also been found that these black spots or better sunspots actively appear and disappears with a period of about 10 years. These sunspots, like freckles in spring, come out in ever-increasing numbers from year to year. This build-up continues for about three to four years until a maximum is reached. After this, the sunspots begin to diminish. The mean time interval between two maxima of sunspots is about 11 years. This period is called the cycle of solar activity.
The modern idea is that the sunspots are gaseous masses which come out from the interior. They cause much disturbances in the magnetic field which in turn affects the trans mission of radio waves. The disturbances are known Magnetic Storms.
"The world is a book, and those who do not travel read only a page", St. Augustine said. Here at www.travel-university.org we believe that every page must be read and explored. Travel is an avenue of learning that no text or classroom can teach. The world is a living classroom and you the student. We invite you to the www.travel-university.org library where you can read general interest and detail oriented articles.
