1. The Sun

2. Sun Fact Sheet The Sun is a normal G2 star, one of more than 100 billion stars in our galaxy. Diameter: 1,390,000 km (Earth 12,742 km or nearly 100 times smaller) Mass: 1.1989 x 10 30 kg (333,000 times Earth’s mass) Temperature: 5800 K (surface) 15,600,000 K (core) The Sun contains more than 99.8% of the total mass of the Solar System (Jupiter contains most of the rest). Chemical composition: Hydrogen 92.1% Helium 7.8% Rest of the other 90 naturally occurring elements: 0.1%

3. The Sun and its Planets to Scale

4. Energy is created in the core when hydrogen is fused to helium. This energy flows out from the core by radiation.

5. Fusion 5 Nuclear Fusion Powers the Universe Two nuclei combine into one nucleus plus a nucleon is called nuclear fusion, a nuclear reaction. The picture here illustrates the fusion that releases a lot of energy. Neutron proton

6. Fusion 6 Nuclear Fusion in Stars Stars are giant fusion reactors. Nuclear fusion reactions provide energy in the Sun and other stars. Solar energy drives the weather and makes plants grow. Energy stored in plants sustains animal lives, ours included. The solar system Solar systemSolar system NASA These links may move

7. Fusion 7 In the Sun two Hydrogens fuse together to form a Helium and at the same time release energy in the form of light radiation

8. The seasons occur because the tilt of the Earth's axis keeps a constant orientation as the Earth revolves around the Sun. A. Summer in northern hemisphere. B. Winter in southern hemisphereseasons

9. Sunspots Sunspots appear as dark spots on the surface of the Sun. Temperatures in the dark centers of sunspots drop to about 3700 K (compared to 5700 K for the surrounding photosphere). They typically last for several days, although very large ones may live for several weeks.

10. Fusion 10 The Sun The sun flare  The corona during an eclipse  The aurora corona during an eclipse

11. Fusion 11 The solar surface

12. Fusion 12 Energy we get from the sun comes in waves called Electromagnetic Radiation In this radiation you have all sorts of waves including the colors and visible light.