The document summarizes key characteristics of the sun, including its diameter being 109 times larger than Earth, surface temperature of 5100-6000°C, and composition of 70-80% hydrogen gas. It describes the sun's three-layer atmosphere - the corona, chromosphere, and photosphere - and details their temperatures and appearances. Solar phenomena like sunspots, prominences, and solar flares are discussed in relation to their effects on Earth and technologies. The energy generation process within the sun's core through hydrogen fusion to helium is also summarized.

1. Prepared by : PN WAHYU AKMAL BT HUSSEIN

2.  Characteristic of the sun
 Diameter : 109 times larger than earth
 Mass : 33 420 times the mass of earth
 Density :1485kg/m3 (0.27 x earth)
 Surface temperature : 5100-6000o
C
 Composition : Hydrogen gas (70-80%) & Helium
 Structure of the sun
 Sun’s atmosphere divided into 3 layers :
 Corona,
 Chromosphere
 Photosphere

3.  Corona :
 Thin layer of gas, visible during total solar eclipse
 Bluish white layer
 Temperature : 2,000,000o
C
 Chromosphere
 9600km thick
 Temperature 15,000o
C
 Reddish during solar eclipse
 Photosphere
 Can be seen from earth
 400km thick
 Temperature 6000o
C
 Core
 Temperature 15 000 000o
C
 Hydrogen is changed to helium

5.  Sunspots
 Dark patches
 Magnetically active spots
 Cause changes in earth climate; e.g extreme drought
 Prominences
 Many thousand kilometres from the surface
 Gases (hydrogen & helium which consists of energetic
& electrically charged particles) escape to the outer
space, causes solar wind that will affect :
satellite, radio, television, telegraph and telephone
communications
Climatic disturbances on earth
Aurora (the sky in the polar regions apperas
colourful)

9.  Solar flares
 Huge cloud of hydrogen that causes violent
explosions
 Causes
 disturbances to telecommunication signals
 Changes in earth climate
 Magnet to malfunction in large solar flares
 Energy is generated from the sun when the
hydrogen gas is changed into helium gas.
 Energy is carried to the sun’s surface where
it is released as heat and light

10.  Star : made up of dust and gases (hydrogen
and helium)
 Sun is a star because it is made up of
hydrogen and helium
 Stars can be compared by :
 Size (neutron star -> supergiant star)
 Brightness : depends on surface temperature,
size & distance from earth
 Colour & Temperature: blue coloured has highest
temperature, red coloured have the lowest
temperature

11.  Nebulae is made up of dust and gases
(hydrogen & helium)
 Gravitational attraction will pull them
together and become stronger till a star is
formed
 The attractive force causes the star to
expand & the temperature rise
 The star will become stable if there is a
balance between the force pulling the star
together and the heat pushing the star apart.

13.  When the nuclear fusion of hydrogen and helium
has been completed, the core of the star will
getting smaller and smaller
 A lot of heat is generated and heat up the
outermost layer of the star.
 Hydrogen starts to burn, star will expand and
appears red in colour
 If red giant is not massive, white dwarf is formed
 If red giant is big, a supernova will occur n
neutron star formed
 If the original star is superlarge star, a black hole
will be formed.

15.  Galaxies is a gathering of billions of stars and
planets, dusts and gases.
 3 types of galaxies:
 Spiral
 Elliptical
 Irregular
 Our solar system is in the Milky Way, a spiral
shaped galaxy
 The solar system occupies only a small part of
the Milky Way
 The universe consists of all the matter, energy
and space that exist. It contain billion of
galaxies, stars, planets and particles.