Earth's Tropics of Cancer and Capricorn -
Equator - The Prime Meridian -
the Arctic and Antarctic Circles...
A Hemisphere is half of a sphere, or ball.
People use the word to describe one half of Earth. Geographers, or
people who study Earth, have divided the planet into two sets of two
hemispheres. These are the Northern and Southern hemispheres
and the Eastern and Western hemispheres.
Diagram also shows the Cardinal Points, or Directions, of
North - South and East - West. They can be determined with a Compass
Compass Rose showing the four Cardinal Directions, the four
ordinal directions, plus eight further divisions. - A Magnetic
Compass show the Degrees, away or towards the Magnetic North.
Directions - Video ( 2 mins)
Equator is located at zero degrees latitude. . The equator
divides the planet into the Northern and Southern Hemispheres. On
the equator, the length of day and night are equal every day of the
year - day is always twelve hours long and night is always twelve
hours long. On the Equator, the sun is directly overhead at noon on
the two equinoxes - near March and September 21.
Tropics of Cancer and
Tropic of Cancer and the Tropic of Capricorn each lie at 23.5
degrees latitude. The Tropic of Cancer is located at 23.5° North of
The tropics are the two lines
where the sun is directly overhead at noon on
the two solstices - near June and December 21.
The sun is directly overhead at noon on the
Tropic of Cancer on June 21 (the beginning of
summer in the Northern Hemisphere and the
beginning of winter in the Southern Hemisphere)
and the sun is directly overhead at noon on the
Tropic of Capricorn on December 21 (the
beginning of winter in the Northern Hemisphere
and the beginning of summer in the Southern
The reason for the location
of the Tropic of Cancer and the Tropic of
Capricorn at 23.5° north and south respectively
is due to the axial tilt of the Earth. The Earth
is titled 23.5 degrees from the plane of the
Earth's revolution around the sun each year.
Arctic ( North Pole) and Antarctic ( South Pole) Circles
region of the planet, north of the Arctic Circle, includes
the Arctic Ocean, Greenland, Baffin Island, other smaller northern
islands, and the far northern parts of Europe, Russia (Siberia),
Alaska and Canada.
The Arctic Circle, incidentally, is an imaginary line located at
66º, 30'N latitude, and as a guide defines the southernmost part of
the Arctic. The climate within the Circle is very cold and much of
the area is always covered with ice.
Antarctic Circle has mostly solid Earth under the great
expansion of Ice. The the parallel of latitude that runs 66° 33′ 44″
(or 66.5622°) south of the Equator.
The Polar Days and
In the Arctics
Summer the Sun never sets... - they have a 24 Hour Daylight. They
call it the Mid-night Sun.
Polar Regions experience a period of twenty-four hours' continuous
daylight at least once per year, in mid-summer, - and - a
period of twenty-four hours' continuous night time at least
once per year, in mid-winter.
Longitude and Latitude
( Vertical GMT 0 Deg) - Latitude
( Horizontal - Equator 0 Deg.)
Longitude or Meridians
Another imaginary line
on the globe is the prime meridian. This line runs from the North
Pole to the South Pole. It divides the earth in half from top to
bottom. The prime meridian runs through Greenwich, England. The
Eastern Hemisphere is the area from the prime meridian east to 180°
of longitude. The Western Hemisphere is the area from the prime
meridian west to 180° of longitude.
While the equator divides the Earth into Northern and Southern
Hemispheres, it is the Prime Meridian at zero degrees
longitude and the line of longitude opposite the Prime Meridian
(near the International Date Line) at 180 degrees longitude that
divides the Earth into the Eastern and Western Hemispheres.
The Prime Meridian and all lines of
longitude are completely imaginary lines and have no significance
with regard to the Earth or to its relationship with the sun.
Latitude is the angular
distance of any point on Earth measured north or south of the
equator in degrees, minutes and seconds.
The equator is a line going around Earth and is halfway between the
North and South Poles, it is given a latitude of 0°. Values increase
north of the equator and are considered positive and values south of
the equator decrease and are sometimes considered negative or have
south attached to them. For example, if a latitude of 30°N was
given, this would mean that it was north of the equator. The
latitude -30° or 30°S is a location south of the equator. On a map,
these are the lines running horizontally from east-west.
Latitude lines are also sometimes called
parallels because they are parallel and equidistant from each other.