What do you know about the sun?

Can you imagine the world without any sunlight? Plants and humans would not survive without the Sun’s energy. The Sun is the largest object in the solar system and contains nearly 99 per cent of the solar system’s mass. The sun provides our planet with its energy , in the form of heat and light.

Superstar Sun

The word Sun means ‘yellow dwarf’. The Sun is so named because it is small star, too small to be called a giant or a super giant star. The sun looks bigger than other stars because it is closest to our planet.

The distance between the Sun and the Earth is nearly 150 million kilometres. The Sun contains gases such as hydrogen and helium, which helps in the production of its energy.

The Energy Factory

The Sun is a storehouse of energy. It works like a factory to produce vast amounts of heat and light, with each part of the Sun playing an important role. The core or the centre of the sun is first where the energy is created. Slightly further out from the core is the convective layer. Here, hot gases carrying energy, rise up towards the surface. The energy then moves to the sun’ surface, or the photosphere. Heat and light shout out into space from the Sun’s surface. It takes light about eight minutes to travel from the Sun to the Earth.

Flares and Spots

The Sun is very hot. The temperature at the Sun’s surface is 6,000 degree Celsius (10,800 degree Fahrenheit), while the Sun’s core, it is 15 million degree Clesius (27 million degree Fahrenheit)! The surface of the Sun is grainy because of the hot gas that bubbles up and down. There are also explosions on the Sun’s surface. Big spurts of the glowing gas is called solar flares, burst out and shoot into space. The Sun’s surface also features dark spots of cooler gases. These are known as sunspots.

The Sun is the star at the center of the Solar System. It is almost perfectly spherical in shape and consists of hot plasma interwoven with magnetic fields. Did you know the Sun is the largest object in the solar system? It makes up more than 99.8% of the total mass of the Solar System and its mass is 745 times the mass of all the planets in the solar system put together!

Distance and Dimension

The Sun is at the distance of 150 million kilometres away from us. It is medium sized star with a diameter of 1,400,000 kilometres which makes it 109 times the size of the Earth! T this average distance, light travels from the Sun to the Earth in about 8 minutes and 19 seconds.

Brightness

Have you ever wondered why the Sun appears to be the largest and brightest star in the universe? The reason for this is that the sun is the closest star from the earth. The other stars that dot the night sky are many more millions of miles away from us, which makes them appear to be scattered specks in the sky ! In fact , the sun is so bright that during the day time, the others stars seem to disappear because of the brilliant light of the sun!

Did you know that solar radiations reach the upper atmosphere of the Earth at the rate of 1,366 watts per square metre? This is the energy supplied by around 10-12 bright light bulbs! Sunlight travels towards the earth at a speed of 3,00,000 kilometers per second. However, only a small part of the sun’s energy reaches the earth . Isn’t it interesting to see that despite that there is so much heat that we receive from the sun ? This heat is put to many uses in our lives, about which we will read in a later section.

The Sun’s Rotation

You know that the Earth has a rotation period of 24 hours. What is it the case of the sun? The Sun’s rotation period ranges from 25 to 25 days. Since the sun is a ball of hot gases, every part of the sun does not rotate in the same amount of time. The poles take longer than does the equator, which has a rotation period of 25.4 days.

The Sun came into being 4.6 million years ago. It was formed from a contracting cloud of hot gases and dust. The particles of gas within this contracting cloud were pulled together because of the source of gravity. This gas cloud increased in density and heat over millions of years and underwent chemical processes to gain its present form.

Structure and Composition

The Sun is composed of hydrogen, which makes up 74% of the sun and helium which is about 25%. There is also a tiny fraction of other elements that make the remaining 1% . Hydrogen undergoes the process of nuclear fusion by which it is converted into helium. During the fusion reaction , particles called positron and neutrinos and radiations called gamma ray photos are released. This reaction produces many millions of tons of hot gases and fire. The sun is made up of several layers that surround the core. The core of the sun, which is its centre is where the maximum heat is generated , making the core the hottest part. It is also the densest part of the sun. Are you aware that more than 600 millions tons of hydrogen is converted into helium every second in the sun’s core? The temperature at the core is a whopping 15 million degrees celsius ! The visible part of the sun that appears to be its surface is known as the photosphere. Literally photosphere means, ‘sphere of light’ . The temperature in this part is 6000 degree celsius.