Week One Topic : The Origin and Systems of the Earth


The Big Bang Theory

  • According to the big bang theory, the universe was once very small and very hot, and then it expanded over time until it reached its peak around 13.7 billion years ago.
  • The big bang model also asserts that seconds after the explosion, the surroundings were at a high temperature of about 10 billion degrees Fahrenheit (5.5 billion Celsius) with aggregates of fundamental particles such as neutrons, electrons, and protons.
  • As the universe cooled in later phases, these particles either combined with each other or decayed. The universe was also said to continue to expand.
  • Evidence for the Big Bang includes:
    • all the galaxies are moving away from us
    • the further away a galaxy is, the faster it is moving away.
  • Suggested readings on the formation period of Big Bang and its other components:


Composition of a matter:

  • Atom > Nucleus > (Proton/Neutron/ Electrons) > Quark / Leptons

Basic Building Blocks of Matter

  • Quarks – is an elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei.
  • Leptons – is an elementary, half integer spin (spin 1/2) particle that does not undergo strong interactions.

There are six types of quarks and six types of leptons, both known as flavours.


  • up
  • down
  • charm
  • top
  • strange
  • bottom


  • electron
  • muon
  • tau
  • electron neutrino
  • muon neutrino
  • tau neutrino


An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element. Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and typically a similar number of neutrons. Protons and neutrons are called nucleuons. The protons have a positive electric charge to which it is composed of 2 Up (+2/3) Quarks  and 1 Down (-1/3) Quarks. Neutrons are composed of 2 Down (-1/3) Quarks and 1 Up (+2/3) Quarks. Meanwhile, electrons do not contain quarks as it is a lepton.

Steady State Theory

The theory states that the universe is always expanding. And further claims that the universe has no beginning or end in time, and that the apperance remains the same over time. But then later on was disproved when certain galactic bodies were found at a certain far distances, which then implied that the universe is evolving.

Cosmic Inflation Theory

Inflation refers to the hypothesis that for a very short time, the universe expanded at a sharply increasing rate, rather than at the decreasing rate such like that of a vacuum energy.

It become an accepted hypothesis because it help answer many observations that came from big bang theory.

One observation, is the homogeneity of objects in space. Objects used to be in contact got farther away from each other.

Second observation, the appearance of flatness or smoothness of the universe. The continuous expansion dilutes or gradually loss the curvature of objects. Therefore, some kind of dispersal occurred.

Third observation, something to do with the formation of stars and star systems in later years. Gravity attract gas into masses, arising to the birth of stars and eventually galaxies.



Nebular Hypothesis

It was the model used to explain the formation and evolution of the solar system.

A star system was formed from a rotating gas cloud or nebula of extremely hot gas. When the gas cooled, the nebula began to shrink, and as it became smaller, it rotated faster, forming a disklike shape (accretion). The nebula’s rotation and gravitational force from the mass of the nebula formed the rings of gas outside. As the nebula, continued to shrink, these rings condensed into various densities of planets and their satellites.


The Planetesimal and Tidal Theories

The formation of planets was explained. The gravitational pull of the passing star raised tides found on the surface of the sun. Some of this erupted matter was detached and plunged into elliptical orbits around the sun. Some of the smaller masses quickly cooled to become solid space, eventually forming larger clumps and gathering more and more matter.

At the present, the four inner planets are called terrestrial or telluric planets because they have solid surfaces and are mostly of silicate rocks and metals. These were Mercury, Venus, Earth and Mars.

The four outer planets are called gas planets because they are made up of only primary materials (helium and hydrogen) that make up the sun. The lower temperature, known to be observed beyond the frost line, allowed the condensation of gas, forming a less dense huge planet. These were Jupiter, Saturn, Uranus, and Neptune.



Other sources you can visit:

(Click on any following topic below to direct you to the main website.)

Origins of the Universe

7 Mind Blowing Facts About the Universe

Big Bang and Inflation Theory

Cosmic Inflation and Big Bang: Infographics


The 10 Weirdest Objects in the Universe



  • Wikipedia
  • Earth and Life Science (Diwa Senior High School Series) by Glen Mangali and Mylene Oliva
  • Conceptual Physical Science 3rd Edition by Paul Hewitt, John Suchoki, and Leslie Hewitt

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