Nebular Hypothesis and Solar System

Era of Nuclei

• Characterized by the formation of atomic nuclei, primarily hydrogen and helium, in the early universe.
• Occurred shortly after the Big Bang when temperatures and densities decreased enough for protons and neutrons to combine.

Jovian/Gas Giant Planets

• Mainly composed of hydrogen and helium, with traces of heavier elements.
• Large atmospheres surround small rocky cores, leading to significant differentiation in structure and composition.

Nebular Hypothesis

• Proposes that the solar system formed from a rotating disk of gas and dust known as the solar nebula.
• The process involves the gravitational collapse of this nebula, leading to the formation of the Sun and planets.

George Lemaitre's Proposal

• Proposed the idea of an expanding universe, leading to the formulation of what is now known as the Big Bang theory.
• Suggested that the universe originated from a "primeval atom," which underwent rapid expansion.

Protoplanet

• A large body formed through the accumulation of dust and gas in a protoplanetary disk.
• Represents a stage in the development of a planet, before it becomes fully formed.

Primary Composition of Jovian/Gas Giant Planets

• Dominantly hydrogen and helium, which contributes to their low density compared to terrestrial planets.
• Envelopes of gases extend to large diameters, characterized by a lack of solid surface.

Smallest Particle of Light

• Referred to as a "photon."
• Represents a fundamental particle in quantum mechanics, crucial in the study of light and electromagnetic radiation.