Astronomy: Solar Nebular Disc Model

Solar Nebular Disc Model

• Stars originate from the collapse of a giant molecular cloud composed of gas and dust.
• The collapse results in the coalescence of smaller clumps that lead to the formation of a spinning disc around a central protostar.
• Planets emerge as a byproduct of stellar formation within this disc.

Protoplanet Hypothesis

• As gas and dust accumulate, a disc forms around a new star, containing minute particles.
• This disc leads to the creation of planetesimals—small bodies that can collide and merge.
• The collisions of planetesimals result in the formation of protoplanets, which eventually evolve into the planets we know today.
• The hypothesis is reinforced by contemporary understanding of fluid dynamics, chemistry, and advancements in astronomy.

Evolution of the Universe

• The universe began as an incredibly hot, dense state commonly referred to as a "tiny star."
• A rapid period of exponential inflation occurred, giving rise to fundamental particles such as quarks, hadrons, and leptons.
• Big Bang nucleosynthesis resulted in the formation of the first atomic nuclei, primarily hydrogen, helium, and lithium, during a cooling phase.
• Following the initial cooling, the universe transitioned into a matter-dominated era marked by the aggregation of stars, clouds, and galaxies, fostering the creation of heavier elements.
• Eventually, dark energy became the dominant force, leading to the accelerated expansion of the universe.
• It is within this context of cosmic evolution that the solar system formed.