Folio Star & Galaxy

MAKTAB RENDAH SAINS MARA KOTA PUTRA JALAN BUKIT KELUANG, 22200 BESUT TERENGGANU SCIENCE FORM 2

NAME: MUHD FARID TAQIUDDIN ZULKIFLY FORM: 2 B COLLAGE NO: 08147

Chapter 9: Star and Galaxies

i)

The Sun

ii) The Stars and the Galaxies in the universe iii) Existence of the Universe as a Gift from God

- the centre of our solar system - The Sun is actually a star of moderate size - The Sun takes 25 and half days to rotate on its axis from west to east

Photograph 9.1: The Sun Characteristics of

Measurement

The Sun Size ( diameter) Mass

1.4 million km 1.989 x 10 kg 30

Density

1.41 g cm ( compared with density of

Surface temperature Temperature of Sun’s

water ) 6000 degree Celsius 15 million degree Celsius

Core Table 9.1: Characteristics of the Sun Notes: - The Sun’s diameter is 109 times the diameter of the Earth - The Sun’s mass is 330 thousand times the mass of the Earth - The density of the material that forms the sun is one over four times that of the Earth

Structure of the Sun…..

Figure 9.1: The structure of the Sun

The Sun’s atmosphere consists of three parts. The parts are, i)

corona

ii)

chromosphere

iii)

photosphere

Characteristic of…

Corona… - outer most layer of gas in the Sun’s atmosphere - corona forms a circle of white light around the Sun - only visible during eclipse of the Sun - temperature is about 1.5 million degree Celsius

Chromosphere… - bright red layer of gas below the corona - only visible during eclipse of the Sun just like the corona - temperature varies between 10 000 and 500 000 degree Celsius

Photosphere…. - compact layer of gas seen to be shining with yellow light from Earth - Photosphere’s surface appears turbulent because gas from the Sun’s core is release to its surface

- This layer is responsible for radiating heat and light from the Sun

Sun’s Core… - consist of hydrogen and helium gases - nuclear reaction occurs in the core all the time to generate and release heat and light energy - The core’s temperature is extremely high. It’s about 15 million degree Celsius

Photograph 9.2: corona and chromosphere can only during an eclipse of the Sun

be seen

Phenomena of that occur at the Sun’s atmosphere… Few of phenomena that occur at the Sun’s atmosphere are

i)

prominences

ii)

Solar flares

iii)

Sunspots

Figure 9.2: Figure above shown prominence, solar flare and sunspot

Phenomena

Descriptions -

an explosion of hot gas that shoots out from the Sun’s chromosphere with shiny bright light

Prominence -

can been seen near the edge of the Sun during an eclipse of the Sun

-

prominence

emits

charged

particles

and

ultraviolet rays into outer space -

a strong explosion of gases that happen suddenly into outer space

Solar layer

-

also emit rays like gamma rays and X-rays

-

this

phenomena

occurs

for

only

a

few

minutes or a few hours but it release a great

Sunspot

-

deal of energy dark spots on the surface of the Sun’s Photosphere

-

has

a lower

temperature ( 4000

degree

Celsius ) than its surroundings ( 6000 degree Celsius )

Table 9.2: Description of phenomena of that occur at the Sun’s atmosphere

The effect of the phenomena on the surface of the Sun on Earth… -

charged particles as a result of solar flares reach the North Pole or the South Pole of the Earth and collide with gas molecules in the atmosphere

-

as a result, colorful light that consist of green, yellow and red lights are produced. These light that can be seen at night are called aurora

-

the charged particles and radiation from the Sun like cosmic rays, X-rays and gamma rays will collide with particles in the Earth’s atmosphere

-

this causes disturbance to the communications system like television and radio broadcast, telegraph transmissions and telephone calls.

Photograph 9.3: Aurora that happen on Earth

Generation of energy by the Sun… - consist of hydrogen and helium gases - nuclear reaction that takes place in the Sun’s core generates energy - during a nuclear reaction, 2 hydrogen atoms fuse to form one helium atom. Heat and light energy are released

Figure 9.3: Nuclear reaction that occur in the Sun’s core

Star is… - a natural object in outer space that can release heat and light energy - generates energy through nuclear reactions

Sun is… - a star that is nearest to Earth

Distance of a star from the Earth is measured in units of light year, distance traveled by light in a year. There are bright stars in the sky can been seen by naked eye at night such as the Sirius and Rigel.

Science Corridor: - Alpha Proxima is the second nearest star to earth. This star is situated about 4.2 light years from Earth - Sirius and Rigel are situated 8.6 and 900 light years respectively from Earth

Classification of stars

Stars need to be classified to facilitate research and classified according to characteristics such as i)

temperature

ii)

size

iii)

brightness

A star with very lo temperature is red in colour. A star that very hot is blue in colour. Dwarf star

- very small star, smaller than Earth

Giant star

- tens of times bigger than the Sun

Supergiant star - very big star, 100 times bigger than the Sun Apparent magnitude - measurement of the brightness of object in the sky that can be seen from Earth. The lower the magnitude value, the brighter the object

Figure 9.4: Apparent magnitude reading

Birth and death of star… Star

- born from nebula

Nebula - a large cloud that consist of dust and gases - gases and particles in the nebula are pulled by strong gravitational force to form a lump and causes the lump of gases to shirk and is compressed until it becomes very compact to form a core - when temperature and pressure in the core become very high, nuclear reaction occurs and hydrogen gas is turned into helium. A lot of heat and light energy are released the, the core shines and a star is born.

The star will die when all hydrogen gas in its core is used up in nuclear reaction. The star will undergo death in by following stages with…

A star of moderate size like Sun: 1. the hydrogen atoms in the star are used up and nuclear reaction stops 2. the star expands because its gravitational force has decreased and forms a red giant 3. the outer parts of the star drift out into space leaving the extremely hot white core called the white dwarf 4. the with dwarf is a star that is dense, compact and becoming increasingly cold 5. the, its continues to become colder and eventually leaves a black body or black dwarf (looks dark in outer space)

A star that is bigger than the Sun:

1. the outer layer of the star expands as a result of decreasing gravitational force to form a red giant 2.

it

continues

to

expand

and

finally

explodes

as

supernova. A great deal of heat and light energy are produced 3. very strong gravitational force in the core of the star converts it into either a neutron star or black hole.

Black hole - an object that is very dense and has strong gravitational

force

that

pulls

all

surrounding

materials,

including light, that is close by, to it. Black hole also can’t be seen in outer space.

Neutron star - a very small and dense star as it consist mainly of neutron particles.

Constellation… Constellation - a group of stars that forms a certain pattern in the sky - in ancient times, knowledge of the constellation were used as a calendar and compass

Figure 9.5: Example of constellations

Types of galaxy… Classified according to: - elliptical galaxies - spiral galaxies - irregular galaxies

Shape of galaxy Elliptical Spiral Irregular

Example of galaxy Galaxy M87 in Virgo Milky Way and Andromeda Magellan Cloud

Table 9.3: Shows the shape and example of galaxy

- our solar is in a galaxy called the Milky Way. - The Sun is one of the millions of stars in the Milky Way.

Many scientist believe in the theory that the Universe begins with a huge explosion, the Big Bang. During the explosion, the Universe expanded from nothing to become a huge space measuring 2 billion billion kilometers in width, in a single second. At present, scientists still can’t explain why the Big Bang occur. We should appreciate the uniqueness, orderliness, beauty and harmony in the Universe as a sing Of the glory of God.