Solar System Formation and Earth's Structure

Accretion Theory

The Sun passed through a huge cloud of interstellar dust and gas, which led to the separation and formation of the Sun and planets. After its formation, the Earth had a core, stratified mantle, and crust. It was bombarded by meteorites and asteroids, which generated internal heat that melted the dust. As the crust formed, it was at a high temperature but eventually cooled, allowing water vapor to condense and begin to form rain and oceans through volcanism. Subsequently, gas emission created a primitive secondary atmosphere in which water vapor was abundant, along with carbon dioxide and other gases.

Layers of the Sun

• Nucleus: Thermonuclear reactions provide energy. It consists of approximately 49% Hydrogen, 49% Helium, and 2% other elements that act as thermonuclear catalysts.
• Radiative Zone: Composed of plasma (ionized helium and hydrogen).
• Convective Zone: This area extends beyond the heating zone; the gas is no longer ionized, and photons are absorbed easily. Energy transport occurs via convection.
• Photosphere: The visible surface area from which most solar light is emitted. It is formed by shining granules projecting on a dark background.
• Chromosphere: The more tenuous upper atmosphere above the photosphere.
• Corona: The outermost layer covering the circumference of the Sun.

The Sun

The Sun is a middle-aged star, orange and yellow, that emits plasma in the form of light, gamma rays, X-rays, ultraviolet, infrared, and radio waves. Its gravity is 28 times greater than Earth's. Light takes approximately 8 minutes to reach Earth. Its diameter is 109 times larger than Earth's. When dealing with time measurements, times added are to the right, and times subtracted are to the left.

Map Projections

• Cylindrical Projection: This projection is most commonly used in planispheres.
• Conical Projection: This projection uses a cone tangent to the globe, positioned so that the vertex of the cone coincides with the pole.
• Azimuthal Projection (Elliptical Projection).

Earth's Composition

The Earth is made up of the following layers:

• Geosphere: The solid part of the Earth.
• Hydrosphere: The material system composed of water found below and on the crust.
• Atmosphere: The layer of gas surrounding the Earth, composed primarily of Nitrogen (79%), Oxygen (21%), and 1% Noble Gases.
• Biosphere: The material system consisting of all living beings on the planet, along with the surrounding physical environment.

Internal Layers:

• Core: The deepest layer, with a temperature of 5000°C, composed of solid iron and nickel (inner core) and liquid (outer core).
• Mantle: The layer below the core, made up of magma and rock.
• Mohorovičić Discontinuity: The zone separating the mantle and the crust.
• Crust: The outermost layer of the Earth.

Earth's History and Crust

About 4.5 billion years ago, the Earth formed. The crust consists of a basaltic layer, a water layer, mountains, granitic rocks, and a sedimentary layer forming the continents.

Minerals

A mineral is a partnership of two or more mineral elements, such as calcium, iron, silicon, oxygen, potassium, hydrogen, etc.