Our Sun


Our Sun is our closest star to our Earth. It is at least 4.5 billion years old. Without the Sun, the Earth would not be able to support life.

Our Sun Picture

How does the Sun work?

The Sun stays lit by converting hydrogen into helium like a big atomic furnace. As a result, tremendous amount of energy is released. The energy is so great that the Sun gives off 40,000 watts of light from every square inch of its surface!

Why is it important?

The Sun is important because it provides the Earth heat, it creates our daylight by emiting electromagnetic radiation, it allows plants to grow via photosynthesis which in turn absorb carbon dioxide and create oxygen. It is one of the prime ingredidents for most Earth life-forms.

There are exeptions such as an lifeforms which have been found near ultra-hot underwater volcanic vents.

Facts about Our Sun

* The Sun’s temperature: 10,000 degrees Fahrenheit at the surface and 27,000,000 degrees Fahrenheit at the center.

*  Distance from Earth: 149 million Kms

*  The Sun’s composition (by weight): 70% hydrogen, 28% helium, 1.5% carbon, nitrogen, and oxygen and 0.5% all other elements.

*  Size: 870,000 miles in diameter, 109 times larger than the Earth’s.

*  Average Distance from the Earth: 93,000,000 miles. It takes light 8 and 1/2 minutes to travel from the Sun to the Earth.


The Sun is about 4.5 billion year old star. It is in the middle phase of its existance.

Sun’s Composition:

The Sun is consists of six parts:

1. The Core is the centre. This is where hydrogen is converted into helium.

2. The Radiation Zone is above the core.

3. The Convection Zone is the outer part of the Sun’s interior.

4. The photosphere is above the convection zone and is the part of the Sun that we see.

What part of the Sun do we see from Earth?
The part of the Sun that we see from Earth is called the photosphere. It is the Sun’s lower atmosphere. Although it is only a few hundred miles thick, it gives off most of its energy as visible light and heat.

5. The chromosphere is above the photosphere. During solar eclipses it can be seen when the much brighter photosphere is blocked out by the Moon.

6. The Corona is the outermost layer of the Sun. It is the hottest part of the surface of the Sun. It extends millions of kilometers into space and is a million times fainter than the photosphere. It has temperatures reaching millions of degrees. The corona can be seen only during solar eclipses because it is millions of times fainter than the photosphere. Specially designed scientific instruments called coronagraphs can also observe it.

Life on Earth

We rely on our Sun for our very existence. Without the sun, nothing can grow on our planet. Because our sun is our only natural resource for heat and light, our planet will go into a deep freeze, when our Sun dies. The surface of the sun is an inferno of helium and hydrogen gas reacting in a violent thermonuclear manner, flooding the solar system with light.


Our Sun’s size is massive, about 3 million miles around its equator. The Sun travels about 700, 000 miles per hour, hurtling through space carrying all planets including us on Earth with it.

Solar Flares

Solar flares are huge explosions of energy that form in the Sun’s core, then sent into space. On Planet Earth they can sometimes be viewed, they are called aurorae.


Sunspots are dark markings in the granulation of the solar photosphere. Sunspots are the centers of intense localized magnetic fields and represent the most obvious manifestations of solar activity.


Scientists can’t study the Sun through X-ray telescopes on Earth since the Earth’s atmosphere absorbs X-rays, solar X-rays can only be studied from spacecraft above our atmosphere.

Many spacecraft have studied our Sun. These include SOHO ( ESA’s Solar and Heliospheric Observatory) and Ulysses.

What Will Happen to Our Sun?

In a couple billion years from today, our Sun will run out of hydrogen and the star will begin to contract. This contraction will cause energy in the core to blaze even hotter then now. This new energy will force the outer layers away from the core and our Sun will become a Red Giant. Its size will grow about one hundred times it’s present size and it will burn 500 times brighter. Planet Earth will become a sea of hot, molten lava everywhere. The Sun will then begin to shrink into a white dwarf star.

Questions – Test your knowledge

How Does the Sun Stay lit?

How long does it take light to travel from the Sun to Earth?
Light from the Sun takes eight minutes to reach Earth.

Is our sun a star?

What is the name of the Sun?
Our sun’s star name is Sol.

Sunrise - Our Sun

Did you know?

  • The Sun is big enough to hold over 1 million Earths.
  • Many rituals and monuments are devoted to worshipping the Sun and/or marking important times in the Earth’s orbit around the Sun.
  • A star is called a ‘sun’ if it is the center of a planetary system.

Warning! Do not look at the Sun directly or you may damage your eyes. This includes telescopes, certain cameras and binoculars.

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