9. stars and galaxies

STARS AND GALAXIESThe Sun

1. Sun is necessary for us, made up of hot gasses (hydrogen), 150 million km, 100x wider than the Earth. Temperature 5500°C - 6000°C.

2. The structure of the Sun. See above diagrams

Photosphere

•Consider the surface of Sun•Light ball (luminous surface) visible from the Earth•All the light energy received , comes from the photosphere.

Core•Center of The Sun•Temperature 15000000 °C•Hidrogen change into helium and release huge amount of energy

Corona

•Only can be seen during Eclipse•Appears as ring of whitish blue light

Chromosphere•Layer made up of Hydrogen, Helium and Calcium•Only can be seen during Eclipse•Appears as ring of purplish red light

STARS AND GALAXIESThe phenomena on the surface of the Sun

sunspot

prominences

Solar flare

Solar flare on 31st august 2012

The effect of solar flares and prominences on the earth

1. Release solar material (consists of hot electrical charged & magnetised particles) into space travelling at supersonic speed

2. The continuous flow of these particles called solar wind that flows past the earth & affect people. See pg 181

The effect of solar flares and prominences on the earth3. The other effect is aurorae. The solar wind collide with oxygen &

nitrogen, causing them release energy in the form of light. North & south poles

aurorae

How energy generated by the sun1. Through nuclear fusion (nuclear reaction) in the core

producing large amount of energy.2. Under high temperature, hydrogen undergo nuclear

fusion to form helium produces energy in the form of light and heat

3. Hydrogen atoms nuclear fusion helium atoms + energy

Various types of stars (pg 184)

Born and death of a star

The galaxies

elliptical

irregular

spiral