Solar System
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Solar System
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Post Icon Solar System

The solar system is the arrangement of the planets in space in relation to the position of the sun. During the day, we see the sun floating in space. During the night, we see the moon and other heavenly bodies floating in space.
The solar system is made up of several components. The main ones are the Sun, Planets, Moon, Asteroids, Meteors, Comets, Satellites, Meteorites, Dust, and Gases.
The sun is at the center and all planets and other bodies revolve around it in elliptical orbits.
Each planet in the solar system is illuminated by light and heat from the sun.
The sun is one of many stars in the great space.
The sun looks bigger because it is closer to the earth than other stars. The diameter of the sun is 1.4million kilometers the sun is not solid like the earth, but it is a mass of hot gases. The average temperature of the sun at its surface is about 6000°c.
                                             USES OF SUN
Plant use energy from the sun to manufacture their food through the process of photosynthesis.
The soil is formed as a result of the complicated interaction of process that involves temperature and other factors.
Coal used in industries and domestic use is solar energy stored in the bodies of the plant which were buried under the earth for a very long period.
Energy from the sun plays a major role in the rain cycle.
                         THE PLANETS
The word planet is derived from the Greek word ‘'planetes'' which means wonders.
A planet is any bodies that revolve in an orbit around the sun.
There is eight known planet which is:-Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
Note;- Pluto long believed to be the outer most planet in the solar system lost its status as a planet in 2006. This followed the discovery of a new bright planet in 2005 that seems large than Pluto. Pluto lost the status because it does not meet the new definition of a planet.
According to new definition of planet must fulfill the following
It must be in orbit around the sun.
It must be large enough that it takes on a nearly round shape
It must have cleared its orbit of other objects.

The moon is a satellite.
It is the natural satellite of the earth, it is spherical in shape and like planets, the moon is a solid state which reflects light from the sun. The diameter of the Moon is 3,456 kilometer and it is about 375000 kilometers away from the earth. As a satellite, the moon takes 29½days to make a complete revolution around the Earth. The moon also rotates on its axis and takes 27 days to make a complete rotation.
Comets are heavenly bodies revolving around the sun in their own orbits. Each comet has a head and along the tail. Their heads are made up of many particles of dust, rocks and frozen gases. Comets go around the sun and can be seen from the earth only when they come close to the Earth.
Asteroids are irregularly shaped objects that revolve around the sun between the orbits of Mars and Jupiter. They are made of rocky debris and are also known as planetoids.
Satellites are bodies which revolve around the planets. The masses that are part of a solar system including the earth are satellites. Each mass its own satellites. Note that we have natural and artificial satellites. Apart from the earth, other planets with natural satellites are Mars, Jupiter, Saturn, Uranus, and Neptune.
Meteors are small heavenly matter falling from outer space at a very high speed. As they pass through the atmosphere they become hot and disintegrate due to the friction.
Meteorites are meteors that pass through the atmosphere falling as large rocks. These meteorites are made up of nickel, iron or silica fragments of disintegrated meteors.
Meteorites are composed of rocks rich in the mineral such as iron, nickel, and silica.
The craters or depression produced when meteorites land on the surface of the earth have become centers of tourists attraction, example Arizona, USA
Light and heat from the sun are vital for life on the earth.
The moon leads to the rising and falling of ocean water.
Planet earth support life.
Solar energy is the technology of obtaining usable energy from the sun's light.                                            This energy is harnessed through special devices called solar panels. The energy is got through radiation and diffusion.
Radiation is the process by which energy is emitted as particles or waves.
  • Solar energy is used in Heating, Cooking, and Lighting.
  • It also used in Electricity generation.
  • Used by a plant in the photosynthesis process.
  • It is the Source of vitamin D
Solar energy and environmental conservation.
Solar energy is sometimes referred to as a clean fuel. This means that the energy is not harmful to the environment.
In Tanzania, Botswana, Uganda, Rwanda, and Malawi solar energy is tapped and used in a variety of way.
Advantages of solar energy
  • It frees women and children from the job of gathering wood for fuel which takes up to four hours a day.
  • It saves the cost of purchasing charcoal or wood.
  • It keeps the women and children out of the smoke –filled huts that cause respiratory disease and eyes problems.
  • Avoid the danger of children falling into open fires and suffering several burns.
  • Use result in great financial, health, and nutrition benefits.
  • It is cheap compared to alternatives source like oil and is a renewable resource.
The disadvantage of solar energy.
  • In highland areas that are generally cloudy, solar panels do not store enough energy to operate batteries at night.
  • Limited power density
  • It is not available at night when it is most needed.
  • Dense cloud cover reduces the amount of direct solar energy that reaches the earth.
  • Unlike oil, it must be converted to other forms such as batteries so as to be used in vehicle and other means of transport.
Some parts of the earth are covered with water (ocean, sea, lakes, and rivers) and some land. Some parts of the land surface are flat and some are mountainous. There are places with trees and grass while others are completely bare. Our Earth is composed of the atmosphere (air), the hydrosphere (water bodies), the biosphere 9living things), the crust, the mantle, and core.
Water covers more than 71% of the earth surface.
Size of the earth and shape
The planet earth is spherical, it is shape is known as ‘'Oblate spheroid'' that is it flattened at the poles and has a bulge at the equator.
This is shown by measurement, through the pole and the equator. The diameter through the pole is about 12,713km while at the equator it is about 12757km.
The circumference of the earth is believed to be about 40,000km.
Sunrise and sunset
The sun rises and sets at different times on different places of the earth .people in the east see the sun earlier than the people in the west due to earth's rotation from west to east.
Circumnavigation of the earth
If traveling from a certain point of the earth, and you go straight around the earth you will come to the point of origin. The first traveler around the world named Ferdinand Magellan in 1519 to 1522 proved this. Magellan did not encounter an abrupt edge over which he would fall in his voyage.
Aerial Photograph of the earth.
A photograph taken by satellites or an airplane from the air shows that the earth is curved or roundish.
Ship's visibility
If you are in the coast viewing a ship which is far, you will see the suit, then the pipe and eventually the whole ship as it comes closer to the coast. When the ship moves away from it gradually disappears starting with the ship, then the pipe and lastly the suit. If the earth were flat, the ship would have been seen all at once.
Lunar Eclipse
Spherical objects give circular shadows. The shadow of the earth thrown on the moon during a lunar eclipse is always roundish. Therefore, the earth is spherical because it gives a circular or round shadow.
The earth is in the motion all the time. It moves by rotation and revolution, one does not feel the motion because one moves with it. Like all other planets, the earth has two motions. One is known as rotation and other as a revolution. The earth's axis is inclined at an angle of 66½° from the perpendicular.
As a result, the earth and all its horizontal circles like the Equator (0°) and the Tropical of Cancer (23½°N) and Capricorn (23½°S).
This is the spinning of a body on its axis. An axis is an imaginary line joining the North and South poles through the center of a body. The earth is rotating on its axis, which joins the earth's North and South poles through the center.
The rotation of the earth is from west to east. To make a complete rotation the earth takes 24hours.
The following observations illustrate the earth rotate from West to East.
When traveling in a fast moving vehicle, we note that trees and another object on both sides of the road moving in the opposite direction.
In the moving, the sun appears to rise over the eastern horizon.
Throughout the night most of the stars appear to move across the sky from east to west.
It causes day and night
It causes daily rising and falling of tides in oceans.
Deflection of winds and ocean currents.
It leads to a difference of 1 hour between two meridians that are 15° apart.
Coriolis force; - Is the force which causes the winds and ocean currents to bend towards the region of the high regime.
This is the movement of one body around another body. The earth revolves around the sun; it takes the earth 365¼ days (one year) to make one complete revolution around the sun.
This is 366 days every leap year and 365 days for other years.
A leap year is every fourth year.
Process of revolution
Due to the elliptical shape of the earth, the sun is closer to the earth at one period of the year than another.
Aphelion, this is the furthest position of the earth from the Sun. The Aphelion occurs each year on 4th July when it is 152 million kilometers away from the sun.
Perihelion, this is the nearest position of the earth to the sun. It occurs each year on 3rd January at this time the earth is at a distance of 147.3million kilometers away from the sun.
  • Change in position of the mid-day sun at different times of the year.
              a) Equinox; - is the equal day and night, it occurs on 21st March and 23rd September.
              b) Summer solstice; - is the period when the sun is overhead at the tropic of cancer (23½N) in the northern hemisphere.
              c) Winter solstice; - is the period when the sun is overhead on the Tropic of Capricorn in the southern hemisphere. It occurs on 22 December each year.
  • Variation in length of the day and night.
  • Seasons of the year.
             A season is a period of the year separated from another by different temperature condition. There is four seasons of the year namely: - A) autumn, B) summer, C) winter and D) spring.
Between March and September the North Pole experience summer period and southern pole experience winter period.
This is the total or partial cutting off of light received by one space body from another. This occurs when a third space body intercepts the light by passing between the other two. There are two types of eclipse: the Lunar and the Solar.
The Lunar Eclipse
Lunar eclipse (eclipse of the moon) it occurs when the earth passes between the moon and the sun, thus casting a shadow on the moon. A lunar eclipse takes place at night and only during the full moon.
The Solar Eclipse
Solar eclipse (eclipse of the sun) it occurs when the moon passes between the earth and the sun, thus casting its shadow over the earth. Solar eclipses occur during the day. The most recent solar eclipse was in 2005. An eclipse lasts for short time less than seven minutes.
These are angular distance north and south of a fixed line known as the Equator.
The equator is latitude 0° and divided the Earth into two equal halves known as a hemisphere.
-Tropical of cancer (latitude 23½°N)
-Tropical of Capricorn (latitude 23½°S)
-Arctic Circle (latitude 66½°)
-Antarctic Circle (latitude 66°S)
-the North Pole (latitude90-The South Pole (latitude 90°S) 
These are angular distances measured in degree from the center of the earth to the East or West of Prime Meridian.
The prime meridian is longitude 0° and joins the North and South Poles. The prime meridian is also known as Greenwich meridian as it passes through a place called Greenwich in London England. Longitude is numbered from 0° to East and West until they meet at 180th meridian.
-The 180°E and 180°W are the same lines of longitude, the total number of longitude is 360° Circle. Important meridian is 0° longitude which is prime meridian and 180° longitudes where the International Date Line is placed.
  • They describe the location of a place on the Earth east or west of the prime meridian.
  • They are important for cartographers who make maps.
  • They are used by airlines and water transport compares to find out safe air and ocean routes.
  • They are used to find the exact local time of a place.
  • They are used to determine climate.
  • They are used to determine the distance between places.
Longitude and time
Longitude can be used to calculate time.
Since the earth rotates 360° to make one complete rotation in 24hours, it rotates 15° in an hour or it rotates one degree in 4 minutes.
Note: 24hours=360°
-Then if it rotates 15° in one-hour= (60minutes)
-It rotates one degree in 1°×60÷15°=4minutes.
International Date Line is an imaginary line at which a day is gained or lost when it is crossed.
This line follows the meridian of 180° and extends between the North Pole and the South Pole. It is zig-zags at the certain place to enable different parts of the same country to maintain the same time. If one travels eastwards and a crosses the dateline one will gain a day. If one travels westwards across the line, one will lose a day.


(This post was last modified: 11-03-2017 01:40 PM by MyElimu.)
09-11-2017 09:13 AM
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