The formation of planets like Earth and gas giants like Jupiter involves a complex process known as stellar and planetary accretion, which occurred long after the Big Bang. While the Big Bang primarily produced hydrogen and helium, subsequent processes in the early universe led to the formation of heavier elements and the emergence of diverse astronomical objects.
Here's a summary of the formation of planets:
Stellar Nucleosynthesis: Stars are the primary factories for the creation of heavier elements. Inside stars, nuclear fusion reactions occur, where hydrogen nuclei (protons) combine to form helium, releasing tremendous amounts of energy. In the core of more massive stars, these fusion reactions continue, creating progressively heavier elements like carbon, oxygen, and iron through various fusion processes. When stars exhaust their nuclear fuel, they undergo stellar evolution, often ending in a supernova explosion. These explosions scatter the newly synthesized elements into space.
Nebula Formation: Supernova explosions disperse enriched stellar material, including heavier elements, into the surrounding space. These ejected materials mix with the remnants of the original hydrogen and helium from the Big Bang, forming a cloud of gas and dust called a nebula. Nebulas are vast and can span many light-years in size.
Nebular Collapse: Gravitational forces acting on the nebula cause it to collapse under its own weight. This collapse leads to the formation of a dense core, known as a protostar, surrounded by an accretion disk made up of gas and dust. The protostar eventually becomes a fully formed star, while the disk continues to evolve.
Planetesimal Formation: Within the accretion disk, solid particles, known as planetesimals, form through the collision and aggregation of dust grains and small rocky or icy bodies. These planetesimals range in size from meters to kilometers and provide the building blocks for planets.
Planet Formation: Over time, planetesimals collide and merge, gradually growing in size. Through a process called accretion, these bodies accumulate more and more material, eventually forming protoplanets. Protoplanets continue to accrete additional material until they reach a sufficient mass to become fully formed planets.
The formation of gas giants like Jupiter involves a similar process, but with different conditions. In the outer regions of the protoplanetary disk, where temperatures are colder, ices composed of substances like water, ammonia, and methane can condense and contribute to the growth of massive gas-rich planets.
In summary, the formation of planets like Earth and gas giants like Jupiter arose from the evolution of the universe after the Big Bang, involving the synthesis of heavier elements in stars, the dispersal of these elements into space through supernova explosions, and subsequent gravitational collapse and accretion processes within nebulae and protoplanetary disks.