Interesting facts about the Sun, the star that gives us life

Without the Sun there would be no light, no warmth, no rain and no life on Earth. Plants make food from its light, winds and weather are driven by its heat, and our calendars are built on our trip around it. Yet the Sun is just an ordinary star among billions in the universe. Here are interesting facts about the Sun.

The Sun at a glance

How big is the Sun?

The Sun is so huge that about 1.3 million Earths could fit inside it. About 99.8% of the total mass of the solar system is in the Sun alone — all the planets, moons and asteroids together are tiny by comparison. Yet among stars the Sun is only of medium size; there are many stars that could hold millions of Suns.

Why does the Sun shine?

At the Sun's core the temperature and pressure are so high that hydrogen nuclei join together to form helium. This is called "nuclear fusion". In the process a little mass turns into energy — according to Einstein's famous formula E = mc². Every second the Sun turns about 4 million tonnes of mass into energy. That energy spreads through the solar system as light and heat.

Did you know? Sunlight takes about 8 minutes and 20 seconds to reach Earth. So the Sun we see is the Sun as it was 8 minutes ago. But energy made at the Sun's core takes thousands of years just to reach its surface.

Sunspots and the solar cycle

Dark patches called "sunspots" sometimes appear on the Sun's surface. They are a little cooler than their surroundings, so they look dark. Their number rises and falls in a cycle of about 11 years. When there are many sunspots, there are also more solar flares and solar storms, which can disturb satellites and communications. India has sent Aditya-L1 to keep watch on such storms.

The future of the Sun

The Sun has lived about half its life. According to scientists, in about 5 billion years it will start to run out of hydrogen and swell into a "red giant", which may swallow Mercury and Venus. In the end it will shrink into a "white dwarf" about the size of Earth. But all this lies so far in the future that there is no need to worry.

The Sun in Indian culture

• Surya Namaskar is a well-known practice in yoga.
• The Konark Sun Temple in Odisha is built in the shape of a chariot and is a UNESCO World Heritage Site.
• Makar Sankranti marks the Sun's entry into Capricorn, and in Chhath Puja the setting and rising Sun are worshipped — read Interesting facts about Chhath Puja.

A warning: never look at the Sun directly with the naked eye, through binoculars or through a camera — it can damage your eyes permanently. Use only certified solar glasses to watch an eclipse.

More articles: Science · Science questions.