Nebular Theory and Planet Formation

Study Notes

The solar system formed from a nebula, a giant cloud of gas and dust in space.
The nebula consisted of hydrogen, helium, and other ionized gases.
The process began with a shockwave from a supernova or a passing star causing the cloud to collapse.
Gravity pulled the cloud's center inward, increasing its spin speed as it contracted.
As the cloud spun faster, it flattened into a disk called a protoplanetary disk.
The center of the disk eventually became the Sun, and the remaining material formed the planets.
Terrestrial planets, like Mercury, Venus, Earth, and Mars, are closer to the Sun and have higher metallic and silicate compounds.
Jovian planets, like Jupiter, Saturn, Uranus, and Neptune, are farther from the Sun, allowing gas to condense due to lower temperatures.

Planets formed from material ejected from the Sun during a close encounter with another celestial object, such as a star.

A form of the Encounter Theory.
A passing star (intruding star) nearly collided with the Sun, causing it to eject filaments of material.
These filaments condensed into planetesimals, small bodies that eventually collided and fused to form planets.

A near collision between the Sun and a passing star caused hot gas to be ejected from the Sun.
This gas condensed into planets instead of planetesimals.