SUN
• The Sun is a star.
• Our Sun is just like the other stars, we see in the night sky.
• It is also the only star that we see during the daytime.
• It is the closest star to the Earth, about 1.5 million kilometres away.
• It is a huge ball of hot, burning gases.
• The temperature at the centre of the sun is about 15 billion degree Centigrade (°C), and on the surface, it is about 6000 °C.
• The sun has a thin layer of atmosphere called the corona.
• It is this corona that we sometimes see during a solar eclipse.
.jpeg)
Figure 7: The Sun
• The spherical sun has a diameter of 13,92,000 km.
• The sun is so big that a million Earths could fit into it.
• It measures more than a million kilometres across.
• But it is still considered small because stars are usually much larger.
• In fact, the sun is called a dwarf star.
• The sun is made up of about 75% hydrogen and 25% helium.
• Helium is at the centre of the sun.
• The hydrogen around it is constantly changing into helium and this releases heat and light energy.
• This change takes place slowly over time as the hydrogen changes to helium in its core (centre).
• It is this light and heat that we receive on Earth.
• Solar energy is the most important source of energy for us.
• It is almost inexhaustible.
• While sunlight is very important and useful, there is some part of it, called ultraviolet rays, that is harmful to us.
• The Earth's atmosphere has a layer called the ozone layer that protects us from the harmful effects of these rays.
