Unit 3 Earth In relation to the universe.pdf

Unit 3: THE EARTH
IN RELATION TO
THE UNIVERSE

Learning objectives
By the end of this unit, the learner will be able to:
•Identify different components of the universe.
•Describe the Earth and the solar system.
•State the Earth’s movements and their consequences.
•Show the relationship between longitude and time.
•Define latitude and longitude.

Main concepts
A universe: refers to all of space including everything that exists in it.
This includes: the stars, the galaxies, the planets etc.…. Universe also
has empty space with particles and interstellar gas. The universe is also
known as cosmos. It has no specific shape. It is endless space.
Telescope: is a monocular optical instrument that magnifies distant
objects, especially in astronomy.
Astronomy: is the study of physical universe beyond the earth’s
atmosphere, including the process of mapping locations and properties
of the matter and radiation in the universe.
An astronomer: is a scientist person who is expert in astronomy.

Components of the universe
The universe is made of planetary bodies that may be
classified into:
a) Luminous heavenly bodies: these are ones that give out the
light such as the stars, the sun
b) Non-luminous heavenly bodies: these are ones that reflect
and receive the light of or form luminous heavenly bodies
such as the planets, comets, meteors, moons, asteroids,
meteorites, etc…

Sun –Luminous object Moon –Non-Luminous object

Examples of heavenly bodies
❖Stars: are luminous heavenly bodies that produce light.
They often have high temperatures and each star is
associated with planets and moons.
❖The sun: is the only star in the universe that gives out
its own light. It is located in the center of the solar
system.

❖Star clusters: are a group of stars that share a common origin.
They are held together by the force of gravity.
❖Planets: these are heavenly bodies that revolve around the
sun following definite paths (specific orbits)
❖Moon: is a natural satellite that reflects the sun’s light to the
earth’s surface. Universally, there are 179moons
❖Asteroids: are small, airless rocky bodies revolving around
the sun. They are located between Mars and Jupiter, they also
are too small to be called planets because they never fully
developed into planets. They are sometimes referred to as
planetoids or dwarf planets.

❖Meteors: are fragments of rock and metal that fall to Earth from space.
✓They form when asteroids break away, and they are different in
sizes.
✓Some are as a fraction of millimeters while other are as bigger as a
football pitch or bigger.
✓They increase the speed as they come closer to the earth due to the
earth’s gravitation forces.
✓They rapidly slow down as they enter earth’s thick atmosphere due
to friction.
✓They then glow, swashing, across the sky like fireworks, before
crashing to the ground. They are also known as shooting stars
✓When they enter the earth’s atmosphere, they appear as short-lived
long lines of light. This light disappears into vapour or ash.

❖Meteorites: are the meteors that fail to vapourise or burn up
before reaching the earth’s surface.
➢Some hit the earth’s with a great impact forming craters.
➢Some meteorites reach the earth’s surface
before they burn up because of the following
reasons:
• They burn before they reach
the earth’s surface
• The most of them land onto
the moon’s surface because
there are many craters on it

The Pingualuit Crater in Canada was formed by a
meteorite plummeting from space over one and a
half million years ago

Lonar Crater Lake Meteorite in India was created by
Meteorites that hit this area approximately 50,000
years ago

❖Constellation: is a group of stars that forms a pattern in
the sky.
There are 88 constellations in our solar system. The most
commonly known are:
The southern Cross referred to as crux which is the
brightest and the Hydra which is the biggest.
Constellations appear in various shapes in form of
animals regarding to people’s beliefs.
Examples: Pegasus, Hydra, Hercules, Andromeda,
Perseus, the southern cross.

The Big Dipper
Southern Cross
The Orion
Perseus

Andromeda
Hydra
Pegasus
Hercules

❖Comets: are heaven bodies that are made up of frozen gases,
ice, and lumps of rocks.
✓They cross orbits of other planets as they move towards
the sun.
✓When they get closer to the sun, the heat vapourises the
frozen gases producing a glowing head called coma and a
tail.
✓This tail extends for millions of kilometers and points
away from the sun. therefore, this tail disappears as the
comets move away the sun, and the gases condense.
N.B: meteors, asteroids are the minor heavenly bodies in the
solar system.

Galaxies
A galaxy: is a big collection of
gas, dust, and billions of stars
held together by the gravity.
One galaxy can also be large as
200,000 light years.
Note that, One light year equals
to 10trillion kilometers.
N.B: Galaxy is different from
constellation at the point that
galaxy is made up of stars, gases,
dust, and other heavenly bodies
while a constellation is made of
stars only.
Milk way galaxy

Examples of galaxies:
❖The Milk way galaxy: it has
a bright central core with a
high density of stars and a
flattened disk surrounding it.
It’s name Milk is derived
from its appearance as a dim
glowing band arching across
the night sky.
NB: Our solar system is
found in milk way galaxy
including the Earth.

This is the
nearest spiral
galaxy to the milk
way galaxy. It gets
its name from
the area of the
sky in which it
appears, the
constellation
Andromeda.
The Andromeda galaxy:

❖Black eye galaxy:
it has a spectacular
dark band of
absorbing dust in
front of the
galaxy’s bright
nucleus, giving rise
to its nickname of
the black eye or
Evil eye galaxy.

❖Bode's galaxy:
this is named by
John Elert Bode
who discovered
this galaxy in1774.
it appears as the
bruised eye.

Its visual appearance is
similar to that of a
spoked cartwheel.
Cartwheel galaxy

Cigar galaxy: this galaxy appears
similar in shape to a cigar.

Comet galaxy: this galaxy
is named after its unusual
appearance. Looking like
a comet

Tadpole galaxy: its names
comes from the resemblance
of the galaxy to a tadpole.
This shape result from tidal
interaction that drew out a
long tidal tail.

• Whirlpool
galaxy: this is
from the
whirlpool
appearance this
gravitationally
disturbed galaxy
exhibits.

1. (a) Define the term universe.
b) Outline the components of the universe.
2. Explain the meaning of a satellite.
3. (a) What is an orbit?
b) Why should planetary bodies revolve around the sun?
4. Describe the difference between the sun and other stars.
5. (a) With specific examples, define the term planet.
b) Explain the characteristics of the moon that is attendant to planet Earth.
6. Describe the following terms as used in geography.
a.Asteroids
b.Planetoids
c.Meteors
d. Meteorites
e. Comets
f. Shooting stars

The earth and the solar system
The word solar derives from a Latin word sol means the sun.
The solar system is a composition of the sun, the planets, and
other small heavenly bodies that revolve around the sun.
The components of the solar system are:
•the sun,
•the eight planets, and
•other small heavenly bodies such as comets, meteors,
asteroids, satellites, gases and dusts.

The sun
•It was formed about 4 to 6 billion
years ago. It forms the central part
of the solar system and all other
bodies revolve around it.
•It rotates in an anticlockwise, it
takes 25 days to complete its
rotation at equator and about 34
to 35 days at the poles.
The sun is a bright sphere which is made up of hot
and burning gases such as Hydrogen and Helium.

•The sun is also a star that gives out its own light. It
provides the energy that support life of plants, animals
and human beings on the earth.
•When it disappears the life on the earth is no longer
possible.
•The structure of the sun is made of the core, the
radiation zone, the convection zone, the photosphere,
the chromosphere, and the corona.
•The temperature on the sun is higher in the inner parts
more than in the outer parts. The light from the sun to
the earth takes 500sec (8minutes).

Why is sunlight dangerous?
The harmful rays of the Sun are called ultraviolet
light. Although we can see them, they are powerful
enough to burn and blister skin.
Sunscreen lotions project us from the Sun’s
ultraviolet light, so if you are outdoors during the
summertime, make sure you slap on some cream
and put on a hat.

The Sun is low in the
sky at sunset or
sunrise, and sunlight
has to travel farther
via the atmosphere to
reach us. Yellow,
orange and red are
scattered the most,
mixing into a fiery
orange.
Why is the sun sets orange?

What turns the sky gray?
Have you ever mixed
all the colors in a
paint-box together and
ended up with a
muddy gray? That is
what happens when
the sky is cloudy. All
the colors of sunlight
are scattered and mix
together.

Why is the sky blue?
As sunlight travels towards the Earth, it has to
pass through the atmosphere.
The atmosphere scatters some of the rainbow
colors of sunlight much more than the others.
Violet, indigo, blue and green are scattered the
most, and they mix together to turn the sky blue.

The planets
Planet: is a heavenly body which:
❖Is oval in shape
❖Is suspended in space
❖Is made up of rocky solids
❖Rotates on its own axis
❖Revolves around the sun
❖Receives the heat from the sun lights
There are 8 planets which are grouped into two
categories

The planets are grouped into two:
The inner/terrestrial planets. They are made up of silicate
rock mantles. Their cores are composed of iron. They are
the planets that are nearer the sun. They are:
✓Mercury
✓Venus
The outer planets/Jovian planets. They are the planets that
are far away from the sun They are:
✓Jupiter
✓Saturn
Jupiter and Saturn are composed of gas while Uranus and
Neptune are composed of ice.
✓Earth
✓Mars
✓Uranus
✓Neptune

Pluto is known as a dwarf planet. It never developed fully. It
is very important to know that Pluto was removed from the list
of planets in 2006, because of the following reasons:
•Its size is too small to be classified as a planet
•It has no uniform revolution round the sun
•Its revolution is not circular but spherical in nature
•Its movement is too slow when compared with the rest of the
planets of our solar system.

Mercury
❖It is the smallest planet
❖It is the nearest planet to
the sun
❖It completes its revolution
in 88days
❖It does not have any
satellite
❖It is about 70 million
kilometers far away from
the sun and 47 million
kilometers close to the sun

Venus
❖It is slightly smaller than the
earth
❖It is the hottest planet in the
solar system
❖It is one of the brightest planets
in the universe
❖It is almost similar to the earth
❖It is moonless
❖It is 108.9 million km from the
sun
❖It takes 225 days or 0.165 earth
year to complete its revolution
around the sun

Earth
❖It is the 3rd planet from the sun.
❖The only planet known to support life (flora and fauna)
❖It is 148 million km from the sun
❖Has one moon called Lunar
❖It is the 5th largest planet in the solar system
❖70% of its surface is covered by water.
❖It completes its revolution within 365 days
❖It completes its rotation on its axis within 24 hours
❖It takes 23hours 56minutes and 4seconds to complete to rotation

Mars
❖It is slightly cooler than
the earth
❖It is 228 million km
from the sun
❖It has 2 moons
❖It takes 686.971 days to
complete its revolution
around the sun

Jupiter
❖It is the largest planet in the
solar system
❖It is made up of cold gases
❖It has 63 moons
❖It take 12 earth years to
around the sun
❖It is 779 million kilometers
from the sun

Saturn
❖It has a ring around it making it unique
❖It has 62 moons
❖It is 1.4 billion kilometers from the sun
❖It takes 29.4 earth years to complete its revolution around
the sun
❖It is made up of ice

Uranus
❖It is the 7th planet from
the sun
❖It is the 8th 2.5billion
kilometers from the sun
❖It has 27 moons
❖It takes 84.3 years to
around the sun
❖It is made up of ice

Neptune
❖It is the 8th planet from
the sun.
❖ It is 4.5 billion kilometres
from the sun.
❖ It has 13 moons.
❖It takes 164.79 Earth
years to complete a
revolution around the sun.

Notes:
❖Venus is the hottest planet in our solar system because it is covered
by a thick layer of clouds composed of carbon dioxide and other
gases, which prevent the heat from the sun from escaping back into
outer space. This is why the planet continues absorbing the heat from
the sun and becomes increasingly hot.
❖Saturn and other outer planets have rings because they have stronger
gravitational pulls that make gases round them in form of rings.
❖Neptune and other outer planets are the coldest planets because they
are the farthest planets from the sun.

Satellites
A satellite is an object that moves around a larger object. The moon is a
satellite because it moves around Earth.
Types of satellites
1. Natural satellite: These are natural heavenly bodies that float around
planets passing through specific paths called orbits.
2. Artificial satellite: These are smaller objects in the outer space made
by humans. They revolve around the planet or the moon. They are
mostly used for:
✓Scientific Research,
✓Communication,
✓Weather Monitoring and
✓Military
Purposes

The moon (Lunar)
➢The moon is a natural satellite of the earth.
➢It reflects the sun’s light to the earth
➢It does not produce any light of its own
➢Its diameter is about 3,476 kilometers
➢It is egg-shaped with the smaller end pointing towards the earth
➢It completes its rotation on its axis in 29days, 12hours, and 44minutes
➢It completes its revolution round the earth in 27days, 7hours, 43
minutes
➢Therefore, the moon completes its rotation and revolution at about
the same time.

Phases of the moon
It refers to the different shapes of the illuminated part of the moon. These
phases are as seen from Earth.
They include:
1. Primary phases.
• New moon
• First quarter
• Full moon
• Last quarter
• Waxing means increasing in size while
• Waning means decreasing in size.
The distance from the moon to the earth varies between 356,334km to
405,503km, i.e.: it is estimated about 384,392kms
2. Intermediate phases.
• Waxing crescent
• Waxing gibbous
• Waning gibbous
• Waning crescent

The moon is completely dark
on the first day. This happens
when the side of the moon that
receives sunlight faces away
from the earth. The new moon
appears when the moon is
aligned with the sun and the
Earth.
New Moon
1. New moon

2. Waxing crescent moon
• Between the 1st and the 6th day after the new moon, the moon
changes. The part that faces the earth begins showing a silver
bright crescent shape.

3. The first quarter moon: 7 days
after the new moon, the moon
completes a quarter of its journey
around the earth. This is when we
are able to see the half of it that
receives sunlight. This happens
when the moon is at a 90° angle to
the earth and sun.

This is the moon
that appears
between day 8
and 13. This
phase appears
when the part of
the moon that
receives sunlight
grows bigger.
4. Waxing gibbous moon

14 days after the new
moon, the moon
completes half of its
revolution around the
earth. Complete circle of
the moon is exposed to
sunlight.
5. Full moon

6. Waning gibbous moon
This phase appears
between 15 to 21 days
after the first phase of
the new moon. From the
earth, we see the lit disk
of the moon decreasing
or waning.

7. Last quarter: This phase appears three weeks after the new moon.
From the earth, we see half of the moon that is lit and half that is
completely dark.

8. Waning crescent: This occurs
23 to 28 days after the new
moon. In this phase, the dark
part of the moon is bigger than
the lit side. From the earth, a
bright crescent is seen. It keeps
on decreasing until the whole
disk of the moon is dark. This
leads to day 0 (New moon)

Characteristics of the moon
❖The moon has a cold surface: the temperature is low because it does
not give its own light
❖It is a dry globe: it has neither rain nor water bodies
❖Its surface is dominated with craters: these are caused by other
heavenly bodies that fall on it with great force.
❖It has no or low gravitation force: the gravitation force on the moon’s
surface is less than that on the earth’s surface. This causes the rising
and falling of sea and ocean waters (Water tides).
❖Its atmosphere is very limited: this means that there is little air
surrounding it.

Notes:
❖The Moon is the only natural satellite of the Earth, and
the only celestial body where humans have landed. It is
approximately 384,403 kilometers (238,857 miles) away
from the Earth, and has an approximate diameter of
3,476 kilometers (2,160 miles).
❖It turns round the earth not the sun because of the
earth’s gravitational pulls is greater than that of the sun.
i.e. the sun doesn’t exert.
❖The moon’s gravitation slow the rotation of the earth but
in over long period of time.

Eclipse
An eclipse is the blocking off of the light of a heavenly
body by another heavenly body that passes in front of it.
An eclipse occurs when the sun or moon is hidden from
an observer on earth. The sun is larger than the earth and
the moon. This results in the formation of zones of
shadows named:
•Umbra: The inner total shadow.
•Penumbra: The outer partial shadow
Types of eclipse
1. Solar eclipse (Eclipse of the sun)
2. Lunar eclipse (Eclipse of the moon)

Eclipse of the moon (lunar eclipse)
This occurs when the earth comes between the moon and the sun. The
earth blocks the sun’s light from reaching the surface of the moon.
Lunar eclipses take place at night and only during the full moon.

Eclipse of the sun (solar eclipse)
This eclipse occurs when the moon comes between the earth
and the sun. It obscures or hides the Earth from the sunlight.
Only a small section of the Earth experiences a total solar
eclipse. It lasts for about 72
1
minutes. The solar eclipse occurs
at daytime.
Moon
Earth
The sun

The characteristics of the earth
• The earth is the third planet from the sun after Mercury, and
Venus.
• It is in the best distance from the sun at which it supports life.
• It ranks 5th size among the planets of the solar system
• It is made up of land (29%) and water (71%) of the total surface
• It was formed about 4.6 million years ago when hot gaseous
materials broke away from the sun
• It is also surrounded by a layer of gas called atmosphere
• Its structure is made up of internal layers (core, mantle, and
crust), and external layers (Hydrosphere, biosphere, lithosphere
and atmosphere)

The shape, size and position of the earth
The earth is egg-oval shaped, it means that it is spheroid or
geoid (not a perfect sphere). The diameter measured at pole is
shorter than that at the equator.
The circumference at pole is about 40,000kms while at the
equator is about 40,075kms. Therefore, the average
circumference is estimated at 40,000kms.
The diameter at poles is measured about 12,722kms while at
the equator is about 12,762kms.
The surface area is 510,000,000 squared kilometers.
The earth is about 148,000,000 kilometers from the sun. it is
the largest planet of the four terrestrial planets.

Evidence for the earth’s shape ( a spheroid)
❖The polar diameter is shorter than that at the equator
❖the circumference at poles smaller from that at the
equator
❖The gravitational pull at poles is greater than that at
the equator because the equator is far from the center
of the earth.
❖Modern satellites show that southern hemisphere is
larger than northern hemisphere
❖The earth is viewed as a circular outline from any
point (sea, ocean)

Evidence to show that the earth is not flat
• Aerial photographs taken using satellites from high altitudes show the earth
is round.
• The shadow cast onto the moon during the lunar eclipse shows the earth is
round.
• Circumnavigation: Movement on the earth along a straight path in one
direction brings you to your starting point from the opposite direction.
• Places on the Earth’s surface do not receive sunshine at the same time.
• The sun keeps changing its altitude at different times of the day. In the
morning and evening, the sun seems to be at a low altitude. At noon, the
sun’s altitude is at a high altitude.
• The Earth’s horizon is curved. The smoke, funnels and mast of the ship
appear on the horizon before the rest of the ship is seen from the coast.
• The polar star looks bigger at the poles and smaller away from the poles.
• All the planets in the solar system are spherical. The Earth being one of the
planets has a similar shape.

The polar star looks
bigger at the poles
and smaller away
from the poles

Photographs taken using satellites
from high altitudes show the earth is
round.

Places on the earth’s surface do not
receive the sunshine at the same time

The shadow casts onto the moon
during the lunar eclipse shows
the earth is round

Uniqueness of the earth
The earth is a unique planet of the solar system that supports life
because of the following reasons:
❖The presence of water with 71% of the total surface of the earth
❖The distance of the earth from the sun makes it not being hot or cold
❖The presence of rain in its atmosphere
❖The existence of gravitation force that support things pull back
❖Presence of gases such as Oxygen necessary for respiration and
Carbon dioxide necessary for plants in manufacturing their own foods,
and facilitate food chain.

Elements of the earth
The earth is made of the following elements:
❖The core: this is the inner layer of the earth that is made of inner
and outer core. The temperature in this layer increases about 4,000
degree Celsius
❖The mantle: this layer is composed of molten materials. It is made
up of lower mantle (asthenosphere) and upper mantle (lithosphere).
❖The crust: it is the outer layer of the earth from the bottom. It is
made of sedimentary, igneous and metamorphic, rocks.
❖The hydrosphere: it is composed of all the water on the earth’s
surface.
❖The atmosphere: this is the outer layer of the earth. It is a gaseous
layer that is made of gases such as Oxygen, Carbon dioxide,
Nitrogen, Helium, Hydrogen and dust

Motions of the earth and their consequences
Motion of the earth is also known the movement of the earth. It is classified into
two types:
a) Rotation: it is the spinning of the earth around itself on its axis in 23hours,
56minutes and 4 seconds which is approximately 24 hours.
b) Revolution: it is when the earth revolve on its orbit around the sun in 365 days
and 6 hours.
The earth’s axis: is an imaginary line believed to cut cross the center of the earth.
The axis has two ends namely:
• North Pole and
• South Pole.
It cuts from the North Pole to the South Pole, and it is inclined at 23o
perpendicular to its orbital plane.

Rotation of the earth and its consequences
The earth completes its rotation in 24 hours in which it is able to
complete 360o from west to east.
It has the following consequences:
❖Rotation of the earth causes day and night
❖It causes the rising and falling of ocean tides (water tides)
❖It causes difference in time between longitudes
❖It causes the deflection of winds and ocean currents
❖It also causes the variation in atmospheric pressure over the earth’s
surface
❖It finally causes the revolution of the moon round the earth.

Figure showing rotation of the earth

Revolution of the earth and its consequences
The earth revolves round the sun from west to east in 365 and 6
hours days. it has the following consequences:
❖Changes in the position of the overhead sun (altitude of the mid-
day sun)
❖Varying length of day and night in different parts of the earth
❖Variation of temperature in different zones of the earth
❖It causes the occurrence of four seasons (autumn, winter, spring,
summer)
❖It causes solstices at tropics, and equinox at equator region

Description of seasons
Season Description
Autumn or
fall
Occurs when summer is ending, temperature
start fall and decreasing towards very cold
conditions.
Winter Very low temperature, severe cold, land mostly
covered by snow in some areas.
Spring Occurs after winter, temperatures begin to
increase leading to summer conditions
Summer A lot of sunshine, high temperature

Dates of the overhead sun
Position of the overhead
sun
Dates
Tropic of cancer (northern
solstice)
June 21st
Equator 21st March and 23rd
September
Tropic of Capricorn
(southern solstice)
22nd December

Lengths of daylight time (sunshine time)
21st March 21st June 23rd
September
22nd
December
12 hours
in all
places
Darkness 24
hours south
pole
Sunshine 24
hours north
pole
12 hours in
all places
Darkness
24hours
North pole
Sunshine 24
hours South
Pole.

Longitudes
Longitudes: are imaginary lines drawn on map crossing from north to
south. They are also the angular distance of a place east or west. They
are measured in degrees, minutes, and seconds east or west.
Major longitudes
1. Longitude 0o (Greenwich Meridian or Prime Meridian): It passes
through Greenland at town near in the U.K hence the name
Greenwich.
2. International Date Line (Longitude 180o): it is 180 degrees east or
west of the Greenwich Meridian
Longitudes are referred to as Meridians after the Prime Meridian. They
are curved in north and south because they meet at north pole and south
pole.

The standard time and time zone
The standard time: is the time recorded by all countries found in
the same geographical region.
It is a time that is agreed by all countries in a given region. For
example: Tanzania, Uganda, and Kenya have the same time.
Importance of standard time is as follow:
▪It helps in making schedules of transport systems
▪It helps in creating schedules of meeting
▪It gives a country a standard time that it is known for
internationally.

Emmanuel
• Lucky Boris
• Adeline
• Nathan Rebero
• Muhizi Isimbi Hagati
• Jean D Amour
• Irasubiza Aime
• Nyamibwa Yvonne
• Jacques
• Digne middle
• Gatesi Kevine Middle
• Niyomukiza Ruth

Time zone
A time zone: is a region that observes a uniform standard time.
Each time zone is 15 degrees of longitudes. The local time is
one hour earlier than the time zone immediately to the east on
the map.
A time zone is very important for commercial, social and legal
purposes.
Time zones follow the boundaries of countries and their
subdivisions because it is inconvenient for areas close to each
other to keep the same time.

International Date Line
International Date Line: refers to an imaginary line of longitude
on the earth’s surface.
It is located at 180 degrees east or west of the Prime Meridian
(Greenwich).
It marks the change from one calendar day to the next. At any
moment, there are two days on earth with the same. A new day
begins at midnight on the International Date line. For example:
if one travels across the International Date line, the date would
change forward or backward.

Countries lie on the Prime
Meridian
Africa
Europe and
Antarctica
• Algeria
• Ghana
• Mali
• Togo
• Burkina Faso
• United kingdom
• Spain
• France

Latitudes
Latitudes: are imaginary lines drawn on a map from west to east. They
are also angular distance of a place north or south of the earth’s
surface.
They are measured in degrees, minutes and seconds north or south.
The zero latitude is referred to as the Equator while other latitudes are
referred to as parallels.
Latitudes are shorter towards north and south poles. They do not meet
and then they form circles around the earth.
the equator divided the earth into two parts known as hemispheres that
indicate north and south

Countries crossed by the Equator
Africa South America and Asia
• São Tomé and Príncipe.
• Gabon.
• Republic of Congo.
• The Democratic Republic of
the Congo.
• Uganda.
• Kenya.
• Somalia.
• Brazil
• Colombia
• Ecuador
• Indonesia

Latitudes and longitudes
Latitudes show how far a place is north or south.
Longitudes help us to determine the time at a given place and
location of different places
Both latitudes and longitudes are used together on a map as
grid that help us to find the exact location of places and
features easily.
When reading the coordinates on a map:
• Latitude is always given before longitude
• Latitudes are parallels but longitudes are not
• Degrees in south and west are sometimes referred to as
negative degrees
• The latitude of a place affects its climate but its longitude
does not.

Calculating local time using longitudes
Steps involved in calculating time using
longitudes:
1. Determine the difference in degrees
between the two longitudes.
2. Find the time based on the difference in
degrees between the two longitudes.
3. Indicate the time regarding to location of
an area.

Example: Calculate the time at Alexandria located at 30° east when the time at
Greenwich is noon.
Solution
Step 1:
Determine the difference in degrees between the two longitudes.
The Prime Meridian and 30°.
0° + 30°= 30° east.
Step 2:
Find the time based on the difference in degrees between the two longitudes.
In this case, if the earth takes 360° to make a complete rotation in 24 hours,
then:
360°= 24 hours
15° = 1 hour
15°= 60 minutes
1° = 4 times

Therefore, 30° = 30° X 4 minutes
=120 minutes
Convert the 120 minutes into hours.
1 hour = 60 minutes
120 minutes = 120:60 = 2 hours
Step 3:
Alexandria is located east of Greenwich. This
implies that the time there is ahead of that at Greenwich. Therefore;
2 hours + time at Greenwich 2 hours +12:000 GMT
=14:00 hrs. (24 hour clock) or 2:00 p.m (12 hour clock)
The time at Alexandra is 14:00 hrs (24-hour clock) or 2:00 p.m (12-
hour clock) when it is noon at Greenwich.

Calculating longitudes using time
Steps involved in calculating longitudes using
time
➢Determine the difference in hours between
two longitudes.
➢Find the longitude based on the difference
in hours between the two longitudes.
➢Indicate the longitudes regarding to the
location of a place.

Example
Calculate the longitude of place X whose local time is 10:00
p.m when the local time at Greenwich is 1:00 p.m.
Step 1:
Find the difference in time between two longitudes.
Time at Greenwich is 1:00 p.m.
Time at location X is 10:00 p.m
1:00 p. m - 10:00 p. m = 9 hours

Step 2:
For every hour, the earth rotates through 15°.
Therefore, in 9 hours the earth will have rotated through
15 × 9 =135°
Step 3:
The time at Greenwich is behind that of location X. This
means that location X is east of Greenwich by 135°.
Therefore location X is 135° east of Greenwich.

Exercises
1. Mr. Kamari took a flight from London at 12 noon to Honiara Island
that is located at 159°E. What time did he arrive at Honiara?
2. It is noon at Manaus in Brazil which is situated at 60°W. What would
be the time in Dhaka located at 90°E?

Homework
1. Determine the longitude of Taipei in Taiwan whose local time is 8:00 PM
when the local time in London is 12 noon.
2. If the local time at station A is 6:30 PM and longitude is 60 degrees west,
what will be the longitude at station B whose time is 4:30 PM?
3. It is 4:00 am at Greenwich; calculate the time at Mogadishu which is located
at 45° east?
4. If it is 12 noon in Kolkata (90°E), what time will it be in New Orleans
(90°W)
5. If it is 12 noon in Cairo (30°E), what time will it be in Shanghai (120°E)
6. The Oscars are being watched in Hollywood (Los Angeles 120°W) at 8:00
PM the show is broadcast live on TV in London at what time?
7. If it is 6:00 PM in Kobe (135°E) what time will it be in New York (75°W)

Unit 3 Earth In relation to the universe.pdf

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Unit 3 Earth In relation to the universe.pdf