Earth, otherwise called the world is the third planet from the Sun, the densest planet in the Solar System, the biggest of the Solar System’s four physical planets, and the main heavenly body known to suit life. It is home to around 8.74 million species.there are in excess of 7.1 billions of people who rely on its biosphere and minerals. The Earth’s human populace is isolated among around two hundred free expresses that connect through diplomacy, conflict, travel, trade, and media.
General Knowledge In various sections like History, Geography, Economics And computers etc. are Most widely Considered in IAS OR PCS Exams, So Here are given some General knowledge Sections On Geography:
Internal Structure Of Earth-
The Earth’s Crust-
* The Outmost solid cover or shell of the earth is known as the earth’s crust.
* The Thickness of the crust is about 30 KM
* It is Thicker in the region of the continents and thinner in the region of the ocean floors.
* The Upper Part of the crust consists of silica and aluminium in greater proportion of silica and magnesium is higher in this part.
* This Layer lies below the crust.
* Its Thickness is about 2900 km and the density of substances in the mantle ranges from 3.0 to 4.7.
* The Earth’s core lies below the mantle. Its thickness may be about 3471 km.
* Its Radius is 6371 km, according to IUGG.
It is divided into two parts:
(a). The Outer Core.
(b). The Inner Core.
* The Outer core is probably in liquid state and the inner core in a solid state.
* The Core mainly consists of iron with some amount of nickel and sulphur (NIFE).
* After the mantle, the earth’s density goes on increasing rapidely towards its center and finaly is more than 13.
* The temperature of the central part of the earth may be about 5000°C.
* The study of the earth’s interior helps us to understand the original rocks in the earth’s crust and their later transformation.
* The solid Parts of the earth’s Crust are called rocks. most of the rocks are made up of two or more monerals.
* In the same type of rocks, the proportions of minerals may be different in different areas.
* Rocks may not always necessarily be hard.
* Minerals are obtained from rocks.
Rocks are classified into tree main types depending on the process of the formation:
* Hot lava pours out at the time of volcanic eruptions and cools down later on, forming rocks.
* The molten materials known as magma, sometimes cool down beneath the earth’s crust, again forming rocks.
* These rocks contain silica from 40 to 80 %, others are feldspar, magnesium and iron etc.
* Other example of these type rocks are granite, Pumic stone, Basalt and Gabbro.
* They are formed by the deposition, sedimenentation and lethification of sediments over a long period of time.
* As layers over layers get deposited, over a period of time, unified Sedimentary Rocks are formed on account of the tremendous pressure exerted by the layers above.
* Sometimes the remains of planets, dead animal etc. are found in the deposited materials. such fossil containing Sedimentary Rocks are useful for studying life on earth.
* Sandstone, limestone, shale are some examples of Sedimentary Rocks.
* The nature of igneous and sedimentary rocks changes due to the effects of tremendous heat or pressure, and new, transformed rocks, called Metamaorphic Rocks.
* Minerals in the rocks get restructured on account of heat and pressure. This brings about a change in the original information of the rocks.
* Some Examples of Metamaorphic Rocks formed from igneous and sedimentary rocks are Gneiss, Homblend, Marble, Graphite coal, Quartzite, Salte, Mica schist.