Forces shaping Earth's formation.

1. Gravity: Gravity is the force that pulls matter together, causing particles to clump together and form larger bodies like planets and stars. It played a key role in the formation of Earth by pulling together the dust and gas in the early solar system to form the planet.

2. Accretion: Accretion is the process by which small particles collide and stick together to form larger bodies. In the early solar system, accretion played a major role in the formation of Earth as dust and gas particles collided and stuck together to form planetesimals, which eventually grew into planets.

3. Heat and pressure: Heat and pressure from the gravitational collapse of the early solar system caused the materials in the protoplanetary disk to heat up and melt, leading to the differentiation of Earth's layers. This process also played a role in shaping the planet's formation.

4. Solar wind and radiation: The solar wind and radiation from the young Sun influenced the composition of the early solar system and may have played a role in shaping the formation of Earth by affecting the distribution of materials in the protoplanetary disk.

5. Impact events: Impact events, such as collisions with other planetesimals or asteroids, played a significant role in shaping Earth's formation. These impacts not only contributed to the growth of the planet by adding material, but also influenced its composition and structure.

6. Tidal forces: Tidal forces from the gravitational interactions between Earth and other celestial bodies, such as the Moon, have also played a role in shaping the planet's formation. These forces can cause changes in the planet's rotation and orbit, as well as affect its internal structure.

Gravitational Accretion:
- The initial formation of Earth began with the accretion of dust and gas from the solar nebula.
- Particles collided and stuck together, forming larger and larger objects until eventually protoplanets emerged.

Core Differentiation:
- Earth's interior gradually melted due to radioactive decay and gravitational compression.
- Denser materials (iron and nickel) sank to the center, forming the core, while lighter elements (silicates and oxygen) rose to the surface.

Lunar Impact Hypothesis:
- A Mars-sized object (Theia) collided with Earth approximately 4.5 billion years ago.
- The impact ejected a vast amount of material into space, which eventually formed the Moon.

Plate Tectonics:
- Earth's lithosphere is divided into tectonic plates that slide past each other.
- These plates interact at boundaries, creating earthquakes, volcanoes, and mountain building.
- Plate tectonics has played a crucial role in shaping Earth's surface features and crustal evolution.

Hydrosphere Formation:
- Water likely arrived on Earth via cometary impacts and outgassing from the mantle.
- As Earth's atmosphere cooled, water condensed and accumulated on the surface, forming oceans.

Atmosphere Formation:
- Earth's early atmosphere was mostly composed of volcanic gases, including carbon dioxide, nitrogen, and water vapor.
- Over time, photosynthesis by early lifeforms released oxygen into the atmosphere.

Erosion and Weathering:
- Physical and chemical processes, such as wind, rain, and glaciers, have eroded and weathered Earth's surface.
- This has created diverse landscapes, from mountains to valleys, and contributed to the formation of soil and rock formations.

Biological Evolution:
- Life has significantly shaped Earth's environment and geology.
- Organisms have produced oxygen, altered the atmosphere's composition, and influenced the formation of sediments and fossil fuels.