Earth internal structure

Earth is the 3rd planet from the Sun at a distance of about 150 million kilometers (93.2 million miles). It takes 365.256 days for the Earth to travel around the Sun. The diameter of the earth is  12,756 kilometers (7,973 miles).Earth is the only planet in the solar system known to hold life. Our planet’s rapid spin and molten nickel-iron core give rise to an extended magnetic field, which, along with the atmosphere, shields us from nearly all of the harmful radiation coming from the Sun and other stars. Earth’s atmosphere protects us from meteors, most of which burn up before they can strike the surface.

Earth is a old English word for land.it belong to galaxy local group. cluster Virgo and super cluster.it is the only planet that hold life. 

WATCH COMPLETE LECTURE ON EARTH STRUCTURE.

Facts about earth:

• sun is not move but other planets are moving.
• It is the third planet and fifth largest planet.
• Its distance from the sun is 149600000 km. Its mass is 5.972 * 10²⁴ kg.
• The Earth was formed approximately 4.54 billion years ago
•  It is the only known planet to support life.

Earth History:

People thing that earth is flat but Aristotle give theory that earth is spherical and the diameter of earth at pole 12715 km(minor axis) at equator its diameter is 12763 km(major axis).

Structure of earth:

Earth divided into four layers:

1) crust  of the earth

2) mantle  of the earth

3) inner core  of the earth

4) outer core of the earth

Crust of the earth

It is outer part of earth.There are two different types of crust: thin oceanic crust that underlies the ocean basins and thicker continental crust that underlies the continents. These two different types of crust are made up of different types of rock. The thin oceanic crust is composed of primarily of basalt and the thicker continental crust is composed primarily of granite. The low density of the thick continental crust allows it to “float” in high relief on the much higher density mantle below also called SIMA layer and SIAL layer.

Mantle of the earth

Earth’s mantle is thought to be composed mainly of olivine-rich rock. The temperature is lowest immediately beneath the crust and increases with depth. The highest temperatures occur where the mantle material is in contact with the heat-producing core. This steady increase of temperature with depth is known as the geothermal gradient. The geothermal gradient is responsible for different rock behaviors and the different rock behaviors are used to divide the mantle into two different zones. Rocks in the upper mantle are cool and brittle, while rocks in the lower mantle are hot and soft  but not molten.Rocks in the upper mantle are brittle enough to break under stress and produce earthquakes. 

Outer core of the earth

Earth’s Core is thought to be composed mainly of an iron and nickel alloy. This composition is assumed based upon calculations of its density and upon the fact that many meteorites are iron-nickel alloys.The outer core is a liquid because the temperatures there are adequate to melt the iron-nickel alloy also called NIFI layer.It is laso contain lighter element such as Si,S,C or O.its ranges is 2900 km to 5150 km and 2300 km thick.

OTHERS USEFULL VUDEOS…

References:

http://solarviews.com/eng/earth.htm

https://readingshouts.wordpress.com/2008/01/21/the-earth/

https://www.arcetri.astro.it/irlab/Astro/solar/earth.htm

https://geology.com/nsta/earth-internal-structure.shtml

https://www.quora.com/What-are-the-characteristics-of-the-mantle