The Planetesimal Theory: Origins of the Solar System

The Planetesimal Theory

The currently accepted scientific model is the Theory of Planetesimals. This framework is consistent with the origin of the universe and the formation of galaxies following the Big Bang.

Core Principles of Planetary Formation

The theory posits that a cloud of gas and dust began to coalesce due to gravity. This process formed a large mass that reached temperatures sufficient to initiate fusion, creating the Sun. The remaining material in the nebula began to cool, with molecular components settling based on their density and mass relative to solar gravitational attraction:

• a. Dense elements and molecules were attracted more strongly to the Sun, forming the terrestrial planets.
• b. Lighter gaseous components were drawn further away, forming the gas giants.
• c. Small solid bodies of varying sizes appeared, attracting one another to create larger, growing masses known as planetesimals.
• d. These planetesimals eventually formed the eight major planets. Asteroids are the remaining planetesimals that were not incorporated into a planet. Beyond Neptune, frozen gaseous remains formed comets. Pluto, along with objects like Sedna and Quaoar, are considered cometary objects captured by the solar system's gravity. Larger satellites formed similarly to planets, while other asteroids and comets were captured by planetary gravity.

The Big Bang and Cosmic Expansion

It is assumed that all existing matter was initially concentrated at a single point known as the "cosmic egg." Approximately 15 billion years ago, extreme pressure, temperature, and gravity triggered a massive explosion. This event propelled matter in all directions at high speeds, a movement that continues today.

As this projected matter cooled, gravitational forces became more effective. Particles began to aggregate, leading to the appearance of gas and dust clouds, which subsequently formed stars. Denser regions formed galaxies, leaving traces of dust and gas (nebulae) between stars. The Big Bang produced an "echo" identified as cosmic microwave background radiation, which can be observed in any direction of our universe using radio telescopes.