Stellar Evolution, Planetary Dynamics, and Earth Systems

The Big Bang event occurred $13.7\text{ billion years ago}$ , when all matter in the universe initially compressed into a single point before rapidly expanding.
Primordial matter consisted almost exclusively of Hydrogen ( $H$ ) and Helium ( $He$ ), which condensed and clumped together under gravity to form interstellar clouds (Nebulas).
Gravitational clumping within a Nebula creates intense heat, generating a Protostar; continuous thermal and gravitational pressure triggers nuclear fusion to form an active star.
Stellar nucleosynthesis inside stars forged every chemical element other than $H$ and $He$ .
All stellar material is recyclable; dying stars distribute heavy elements back into space to form future cosmic structures.

Solar energy emitted by the Sun (light and heat) powers ocean photosynthesis to sustain marine life.
Solar heat drives Earth's hydrologic cycle to maintain a state of perfect balance.
Heat, light, and $H_2O$ drive global weather patterns, atmospheric winds, surface waves, and ocean currents.

Protons ( $p^+$ ) are positively charged subatomic particles inside the nucleus whose total count uniquely defines specific chemical elements.
Neutrons are neutral subatomic particles inside the nucleus; variations in neutron count within an element form isotopes, which can be unstable.
Electrons are negatively charged subatomic particles located outside the atomic nucleus.
Unstable radioactive isotopes emit massive amounts of heat as they undergo nuclear decay.

Planetary accretion occurs as stellar materials and dust clump together around stars.
Terrestrial planets are smaller inner planets composed of gases, rock, and metals (Iron, $Fe$ , and Silicon, $Si$ ); their solid crusts can directly support liquid surface oceans.
Gas giants are massive outer planets composed predominantly of thick gas envelopes; they cannot support surface oceans, though liquid oceans can exist on their moons.
Planetary bodies become density stratified during formation, with denser materials settling in the core and less dense materials remaining on the outside.

The astronomical body Theia collided with early Earth, knocking it onto its axial tilt and ejecting vaporized material into surrounding space.
Vaporized debris from the collision recondensed in orbit to form the Moon.
The lunar surface features craters formed from colliding space debris.
Moon phases and Earth's light and dark sides are dictated by relative orbital location.
The gravitational presence of the Moon produces ocean tides on Earth.

Asteroids are composed of metal and rock, are located in the Asteroid Belt between Mars and Jupiter, and represent a failed planet.
Comets are ice-packed bodies located past Neptune.
Extraterrestrial impacts from asteroids and icy comets represent a minor source of Earth's surface water.
Volcanic outgassing from Earth's interior and core represents the major source of Earth's liquid water.