Study Material on the Earth

The orbit in which the Earth travelled around the Sun is elliptical.  The distance between the Sun and the Earth is minimum on 3rd January and this is called perihelion. The distance between the Sun and the Earth is 9.15 Crore Km on 3rd January. The distance between the Earth and the Sun is maximum on 04th of July and this is called Aphelion. The distance between the Earth and the Sun is 9.45 crore Km on 04the of July. The imaginary line between perihelion and aphelion  is called apside line.

Latitude:- It is the imaginary line on the globe towards West to East, which is represented in degree. Equator is known as zero degree latitude. The north part of equator is called North latitude and south side of equator is called South latitude. Hence, we can say that the North side of equator up to North pole is known as North latitude and the South side of equator up to South pole is known as South latitude. Thus, Pole is called 90° North or South latitude. All the latitudinal lines are parallel. The area between two latitude is called Zone. The distance between two consecutive latitude is 111 Km. The 23½° latitude in north direction of equator is called cancer line while 23½° latitude in south direction of the equator is called  tropic of capricorn.

Longitude:- It is the imaginary line on the globe towards North to South. The longitudinal lines are not parallel. The longitudinal lines are merged together on the North and South pole. The distance between two longitudinal lines are to be increase from pole to equator. The distance of two longitudinal line on equator is approx 111 Km.  The longitudinal line which is passed through Greenwich is known as 0° longitude.  The left side of Greenwich is called Western longitude and the right side of Greenwich is called  Eastern longitude.  The time of a certain place is found on the basis of its longitude. The distance of two longitude is called Gore. Zero degree latitude and zero degree latitude intersects each other in Atlantic Ocean.  The Sun is perpendicular to  the cancer line (23½° N) on 21th of June and this is called  Cancer Solstice. Thus,  21th June is the longest day in North hemisphere. The Sun is perpendicular to capricorn line and this event is called Capricorn Solstice. Thus, 22nd of December is the greatest day of South hemisphere. The Sun light is always perpendicular on equator, so the duration of day and night are on equator. The duration of the day and night in whole world are equal on 21th March and 22nd September. 22 September is also called autumnal equinox and 21 March is called Vernal Equinox.

Lunar Eclipse:-  When the position of the Earth is between the Sun and the Moon then this event is called Lunar Eclipse. We can expressed lunar eclipse in short as "MES" i.e Moon, Earth, Sun i.e Earth is between the Moon and the Sun. The Lunar Eclipse happens in full Moon always. The event of lunar eclipse is not happens in every full Moon because 5° difference between the orbital path of the Earth and the Moon. Lunar Eclipse is happes  maximum 03 (Three) times in a year.

Solar Eclipse:-  When the position of the Moon is between the Sun and the Earth then this event is called Solar Eclipse. We can also expressed this thing is short as "SME" i.e Sun, Moon, Earth i.e The Moon is between the Sun and the Earth. The solar eclipse is always happens on New Moon.  The event of Solar Eclipse is happened 05 (five) time in a year maximum.

International Date Line:-  180° is called International date line. It is declared in International Meridian Conference of Washington in 1884 AD. The International Date line passing through the Arctic sea, Bering straight, Chukchi Sea and Pacific Ocean. The difference of 04 minute in time is with the difference of one longitude. The World is divided in 24 time zone and these time zone are divided in the difference of one hour with time of Greenwich. Thus, we can say that the every longitudinal zone is equal to 15°.  The mean time of every country is decided  as the factor of 30 Minute of Greenwich time. 82½° Eastern longitude is passing Naini (Allahabad) in India and time of this place is called the mean time of India. The mean time of India is 5½ hours ahead to the mean time of Greenwich.

Zone:-  Every hemisphere is divided in many parts on the basis of its temperature and this is called Zone. The zone have four types:-
01. Tropical Zone:- The area of 30° North and 30° South from the equator is called tropical Zone.  The season of this area is always hot.
02. Sub Tropical Zone:-  The area between 30 to 45° North and South from equator is known as Sub Tropical Zone.
03.  Temperature Zone:-  The area between 45° to 66° North and South latitude from the equator is known as Temperature Zone.
04. Polar Zone:-  The area between 66° to 90° North and South latitude from the equator is known as Polar Zone.

Internal Structure of the Earth:-

The internal area of the Earth is divided in to three parts.
01. Crust
02. Mantle
03. Core

Crust:-  The outer part of the Earth is called Crust. The area of the Crust is about 35 Km inward. Crust are made from Basalt rock. Crust have two parts- SIAL and SIMA.
The Silicon and Aluminum are found  in large amount  in SIAL and  Silicon and Magnesium are found abandoned in SIMA. Oxygen (46.5% ),, Silicon (27.8%), Aluminum (8%) are the main element which is found in the Crust.

Mantel:-  The depth of mantel is approx 2900 Km. The chamber of Magma is found in the core of mantel. Its average density is 3.5 to 5.5  gm cubic cm. Mantel is covered almost 83%  volution of the Earth.

Core:- The nucleus of the Earth is called Core.  This area is made from Nickel and Ferrous  (NiFe). Its average density is 13 gm per cubic Cm. The core part of the Earth is in Liquid form. It cover the 16% of the total volume of the Earth.