Lesson 8 - Solar Nebular Theory

What were the 3 early chemical elements in the universe?

• Hydrogen (H)

• Helium (He)

• Lithium (Li)

What is the Galactic Recycling Process?

The process of stars recycling matter and creating new elements

How did the solar system form initially?

Some trigger, like a supernova, sparked the collapse of nebula, which created the Sun and the rest of the solar system

During the creation of the solar system, why did the initial nebular sphere flatten into a disc?

The collapsing material increased the rotation speed of the nebular sphere, which caused angular momentum to flatten it over time

What is the Ice Line?

A point beyond the Sun where temperature drops below freezing. Beyond this point, gaseous compounds such as ammonia and methane can condense to form ice flakes that form the basis for the jovian planets.

What is the Condensation Sequence?

The sequence in which different materials condense from the solar nebula, depending on their distance from the Sun.

What is Condensation?

The growth of a particle by addition of material from the surrounding gas, atom by atom.

What is Accretion?

The sticking together of solid particles to produce a larger particle.

What is a Planetesimal?

A small body that formed from the solar nebula and eventually grew into a protoplanet.

What is a Protoplanet?

Massive object, destined to become a planet, resulting from the coalescence of planetesimals in the solar nebula.

What is Gravitational Collapse?

The process by which a forming body such as a planet (>15 Earth masses) gravitationally captures gas rapidly from the surrounding nebula.

What is Differentiation?

The separation of planetary material inside a planet according to density. Occurs due to gravity compressing the material inward, causing it to melt.

What is Outgassing?

The release of gases from a planet's interior, which may form an atmosphere if gravity is strong enough.

What are Solar Winds?

A continous emission of electrons, protons, and ions spewing out in all directions from the spherical Sun

What do Solar Winds do?

Sweeps away matter close to the terrestrial planets into the Kuiper Belt, keeping them small

What was the Heavy Bombardment era?

The intense cratering that occurred sometime during the first 0.5 billion years in the history of the solar system. Cleared out large accretions that the solar winds could not push out.

To summarize, why is the solar system disc shaped?

Because it was formed by the one single collapsing nebula, with the angular momentum forming the sphere into a disc

To summarize, why do we have Terrestrial and Jovian planets?

Due to the condensation sequence and solar winds, Terrestrials condensed closer to sun, Jovians condensed farther away

To summarize, how do asteroids, comets, and meteors form?

Asteroids form like early terrestrials planets, comets form like early Jovian planets

To summarize, why are all objects in the solar system a similar age?

The solar system was formed by the same collapsing nebula, so everything has the same age