The Sun

1. The Sun Science 9

2. An Important Star • Provides energy for life • Keeps Earth in a steady orbit • It is the closest star to Earth and the brightest object in the sky • It gets its energy from nuclear fusion • Particles come together to form new substances • This produces heat, light and other forms of energy

3. How Old is the Sun? • The Sun is approximately 5 billion years old • it should continue to produce energy for another 5 billion years old • Does this mean that the sun has hit middle age?

4. A Close Look at the Sun • Based on data collected from studies of the Sun, the following terms have been used to describe what is happening on the Sun • Solar flare • Photosphere • Solar prominences • Moving gases • Core • Chromosphere • Corona

5. Characteristics of Other Stars • There are billions of other stars in the universe • Increasing evidence that there are many stars that have planets orbiting them • The colours of stars helps to estimate its temperature – cool glows red, hot glows blue • Spectroscopes are used to help see all the colours a star emits • They help us determine what elements are present on a star and in what quantity

6. Star Light, Star Bright • Stars can be classified according to their brightness • Apparent magnitude is the term used to represent brightness of a star from our position on Earth • Absolute magnitude refers to the actual amount of light given off by a star at a standard distance. • All stars are considered to be the same distance from Earth when this is calculated

7. How Does the Sun Measure Up? • The Sun has the greatest apparent magnitude because it is the closest star to us • However, its absolute magnitude is only considered to be average