Universe and the Solar System

Big Bang theory

* The universe was once very small and very hot
* Surroundings were very hot with aggregates of particles
* Cooling stage allowed other planets to form

Steady State Theory

* The universe is always expanding but maintaining a **constant average density**
* Matter is continuously formed
* Universe has **no beginning and no end**

Cosmic Microwave Background

* **remnant** of the Big Bang Theory
* it is the cooled remnant of the first light that could ever travel freely throughout the Universe

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Cosmic Inflation Theory

* **Rapid expansion** of space-time
* Bubble of pure vacuum energy expanded and exploded - formulation of matter and radiation

Oscillating Theory

* Agrees with the Big Bang theory
* There is a period of expansion and contraction
* “big crunch”

Solar System

gravitational bound system to the sun and the objects that orbit it, composed of the following: sun, planets, asteroids, comets, meteors

Planetesimal and Tidal Theory

* A star passed by the sun
* The star’s **gravitational pull raised tide** and caused detachment of matter
* Pieces of matter soon became planets

Nebular Hypothesis

* Starts from a **gas cloud**
* Gas cloud contracts, cools, and condenses
* Forms a disk and rotated, forming a central mass
* Rings are formed with small masses on each ring

Protoplanet

* Massive cloud of gas and dust rotated slowly in space, the cloud shrank under the **pull of its own gravitation**
* Most materials gathered around its own **center**

Redshift

the **wavelength of the light** is stretched, so the light is seen as ‘**shifted**’ towards the **red part** of the spectrum \[shows that the universe is expanding