Understanding Our Solar System and Earth's Dynamic Geology

The Solar System: Planets and Origins

Planets of Our Solar System

According to the International Astronomical Union (IAU), the planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.

Origin of the Solar System

Observations supporting theories of solar system formation include:

• The Sun and the planets revolve in the same direction.
• The planets travel in nearly circular orbits lying in the same plane.
• The rotation of most planets occurs in the same direction as their convection.
• Planets near the Sun are small and dense, while external planets are large and lightweight.
• All planetary bodies show evidence of large impacts.

The Planetesimal Theory

Designed by astronomers Carl F. Von Weizsäcker and Gerard Kuiper between 1944 and 1950, this theory proposes that the solar system formed approximately 4,500 million years ago from gas and dust within a nebula located in the Milky Way.

Understanding Earth's Interior: Methods and Divisions

Indirect Observation Methods of Earth's Interior

The most common indirect observation methods are based on measuring certain physical properties of the planet.

• Laboratory Testing: Conducted laboratory tests attempt to reproduce the conditions prevailing inside the Earth.
• Study of Seismic Waves and Earthquakes: The study of seismic waves is the indirect method that provides the most comprehensive data on the structure and composition of Earth's interior.

Divisions Within the Earth

The three large layers of the Earth are the core, mantle, and crust. Within these, there are different areas:

• Inner Core: Its center is solid.
• Outer Core: Behaves like a liquid and exhibits convection movements.
• D" Layer (Material Level D): Differentiated material, distinct from the dense core or mantle material.
• Lower Mantle: Constitutes approximately 49.2% of the Earth's volume.
• Mantle Transition Zone: Accounts for about 7.5% of the Earth's volume.
• Upper Mantle: Made up of minerals rich in iron and magnesium.
• Oceanic Crust: Represents approximately 0.099% of the Earth's volume.
• Continental Crust: Represents approximately 0.374% of the Earth's volume.

Plate Tectonics: Earth's Dynamic Surface

What is Plate Tectonics?

The Earth's lithosphere is divided into a series of rigid fragments called lithospheric plates.

• These lithospheric plates are not static; they constantly change in size, shape, and position.
• This dynamic movement produces titanic friction and thrust between the plates, triggering various internal geological processes.

The Edges of the Plates (Plate Boundaries)

The interactions between plates occur at their boundaries:

• Convergent Boundaries: Where two plates collide.
• Divergent Boundaries: Where two plates separate.
• Transform Boundaries (Lateral Motion): Where two plates slide laterally past each other.

Types of Plate Convergence

• Oceanic-Oceanic Convergence: The older, denser oceanic plate subducts beneath the younger one, easily descending into the mantle. This process originates submarine volcanism, whose materials rise to the surface and produce island arcs.
• Oceanic-Continental Convergence: The oceanic lithosphere is introduced (subducts) under the continental lithosphere, which becomes deformed, creating a mountain range.
• Continental-Continental Convergence: When two continental plates collide, neither penetrates deeply into the mantle. Instead, they form an orogenic collision, resulting in large mountain ranges.