Earth

Age of the Earth is equal to 1\3 of the age of the universe- reference in the quran also

Air 78% Nitrogen, 21% Oxygen, 0.9% Argon, 0.04%Carbon dioxide, other gases and water vapour

Earth's structure it used to be hot and a single solid structure. Planetary differentiation divided it into different layers.

Earth's surface 29% is land and 71% water: 97.5% salt water & 2.5% fresh water ~ 69% from glaciers & 30% from groundwater

Mantle The Earth's crust floats over the mantle and its about 2900Km thick. Consists of fixed, solid and rocky material. 85% of earth's total mass

Core Has a radius of 1200km. Its a solid ball made of Iron and Nickel. Its the hottest part of the earth and the temperature is equal to sun's surface temp. 5700 C

Crust Its the outer most layer and accounts to 1% of Earth's volume. The continental crust (25 miles\ 50 km thick) is 3 times thicker than the oceanic crust (3-5 miles\ 8 km thick)

it consists of giant tectonic plates the move around. Those create mountains upon collision and trenches upon being stretched

Upper mantle

Lower mantle\ Outer core 2266 KM thick liquid layer of Iron&Nickel (temp 4000-5700 C)

Lithosphere

Asthenoshphere

Its growing 1mm every year

Atmosphere Atmosphere has different layers surrounding the Earth.

Mesosphere Meteoroids reaching earth get burnt here. Its the coldest place on Earth (avg.temp. -85C). 85Km top height

Thermosphere The lower part of this layer contains ionosphere Most of the atoms are ionized here and contains the electrical charge. Helps in transferring radio waves signals. 400 miles top height

Stratosphere This is where the Ozone layer is and the planes fly here to avoid the weather disturbance. 50km top height

Exosphere 10,000 Km Space starts after this layer.

Troposphere This layer is closest to the earth where weather exists and humans depend on it. 10km above the surface of Earth.