Nebular Hypothesis

Nebular Hypothesis

It is a scientific explanation for the formation of the Solar System.

It proposes that our Solar System, including the Sun, planets, moons, and other celestial bodies, formed from a large cloud of gas and dust known as a solar nebula.

Solar nebulae

these are also known as stellar nurseries.

Pierre-Simon Laplace

He proposed the Nebular Hypothesis

Formation of the Solar Nebula

This stage involves the formation of a large, cold and dense cloud of gas and dust in space.

One disturbance can be an exploding star which is also known as a supernova.

It asserts that gravity played a significant role in the formation of the universe and our Solar System.

Collapse and Flattening

Gravity collapses the nebula inward and flattens it into a disk-shaped cloud.

It asserts that the stronger the gravity, the higher the acceleration for collapsing.

It involves angular momentum; when the radius decreases, the rotational spin increases.

Angualar momentum

when the radius decreases and the rotational spin increases

Protoplanetary Disk Formation

In this stage, an accretion disk is formed.

Accretion disk

this is a flat, rotating disk of gas and dust around the central protostar.

Condensation and Planetesimal Formation

In the colder outer regions, where volatile compounds can exist as solids, tiny dust particles begin to stick together through processes like electrostatic forces and collisions.

These growing clumps of material are called planetesimals.

Planetesimals

these are solid small objects formed due to accumulations and collisions of dust. They serve as precursors to small planets.

Protoplanet Formation

As planetesimals continue to collide and merge, they form larger bodies known as protoplanets.

Orbital resonance is present.

Orbital resonance

this is when the gravity of two celestial bodies affect each other.

Planetary migration.

Over time, these protoplanets migrated to other regions in a process called?

Clearing of the Nebula

Over time, the protostar's radiation and stellar wind begins to clear away the remaining gas and dust in the accretion disk.

At this stage, the central protostar becomes a main sequence star.

This process defines the end of the formation phase.

Terrestrial and Jovian Planet Formation

The composition of the material available at different distances from the Sun influences the types of planets that form.

terrestrial and Jovian planets

There are two types of planets in the Solar System. What are they?

Mercury, Venus, Earth, Mars

The terrestrial planets are:

Jupiter, Saturn

The gas giants are:

Uranus, Neptune

The ice giants are:

Late Stages and Final Arrangements

The final arrangement of the planets is influenced by gravitational interactions and dynamical processes, leading to the configuration we observe in our Solar System today.

Carl Sagan

According to him, “we are made of Star stuff”