The Solar System |
The Constituents of the Solar System
The Solar
System consists of eight planets and the Sun. The other members of the Solar
System are natural satellites, asteroids, comets and meteoroids. The eight
planets in the Solar System beginning with the nearest to the Sun are Mercury, Venus, Earth, Mars, Jupiter,
Saturn, Uranus and Neptune. All the eight planets are moving around the Sun
each following its own oval path called orbit. On August 24, 2006, the International
Astronomical Union (IAU) formally downgraded Pluto from an official planet to a dwarf planet. The time taken for a planet to complete one
revolution around the Sun is different from the time taken for another planet
to do so.
Mercury
Mercury is the closest planet to the
Sun. Since Mercury is closest to the Sun its temperature can be over 300oC
in the daytime. Mercury rotates on its own axis very slowly, making one full
rotation every 59 Earth days.
Venus
Venus is the second planet from the
Sun. The size of Venus is about the same as that of the Earth. The planet is
always covered by a very thick cloud of carbon dioxide and acid vapour. Thus,
the temperature of Venus is extremely hight, even though Venus is twice as far
from the Sun as Mercury and receives only a quarter as much light. As a result,
the surface temperature can be above 450oC. Venus takes about 225
days to revolve around the Sun. It rotates on its own axis once every 243days.
Its gravity is the same as that of the Earth.
Earth
Earth is the third
planet from the Sun. It is the fifth largest planet. It is the only planet with
oxygen and water. Thus, it is the only planet on which living things can
survive and grow. Earth takes about 365 days to revolve around the Sun and rotates
on its own axis once every 24 hours. Earth has a natural satellite (the Moon)
revolving around it.
Mars
Mars is the fourth planet from the Sun. It also known as the Red
Planet because it surface is being covered with red dust. Mars is a cold and
lifeless planet. One revolution of Mars around the Sun takes 687 days.
Jupiter
Jupiter is the largest planet in the Solar System. It is the
fifth planet from the Sun. Most of Jupiter’s volume is made up of gases and ice
with only a small rocky core. The atmosphere is composed of mainly hydrogen in
gaseous and liquid forms together with helium, methane and ammonia. Jupiter has
sixteen natural satellites or moons and takes about 12 years to revolve once
around the Sun.
Saturn
Saturn is the sixth
planet from the Sun. It is surrounded of a system of rings which make it the
most striking and beautiful planet when viewed through a telescope. Saturn is
the second-largest planet in the solar system. However, it is lighter than a
body of water of the same size. Saturn is thought to have a small, rocky
high-temperature core surrounded by ice and ammonia, mixed with grit and gases.The time taken for Saturn to revolve around the Sun is around
29 years.
Uranus
Uranus is the seventh planet from the Sun in the solar system.
This planet is blue because it has cold gases, mainly made up of hydrogen and
helium. Uranus also has a ring around it but the ring cannot be seen clearly
because it is too thin and dim. It has five moons, and it rotates on its own axis
slightly more slowly than Saturn. The time taken for Uranus to revolve around
the Sun is around 84 years.
Neptune
Neptune, the eighth planet from the Sun is
almost the twin of Uranus. It is a little heavier than Uranus and is very
slightly bigger. It is bluish-green.Neptune consists mainly of ice with some
rocks and gases, and has less atmosphere. It has two moons and takes about 165
years to revolve once around the Sun.
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Syabas, penerangan cikgu cukup jelas...
ReplyDeleteTeacher, thanks for the useful notes~
ReplyDeleteUseful information.
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