Origin of the Universe and Solar System

• Is the study of the origin and evolution of the universe.

  Cosmology 
• The Big Bang Theory (BBT)

  The most accepted theory explaining the universe's origin
• According to the BBT

  1. Before the universe (or anything and everything) existed, all matter and energy were condensed into high-temperature and high-density states

  2. Sudden rapid expansion occurred, resulting in an explosion (the Big Bang), which generated all matter and energy, including space and time

  3. After the explosion, the Universe was in a hot and dense state

  4. As expansion continued, the temperatures cooled down and allowed for the formation of light elements such as hydrogen and helium

  5. Nuclear fusion generated other slightly heavier elements

  6. Clumps of matter began to form and grow through accretion, eventually producing the first stars 400 million years after the Big Bang

  7. Supernovas occur at the end of a star's life cycle, generating spectacularly powerful explosions and producing heavier elements

  8. Large masses form into planets, asteroids, and other space bodies

  9. Gravity affects these space bodies, causing them to come together to form galaxies
• The most accepted age of the Universe is 13.8 billion years old, determined by measuring the leftover radiation from the Big Bang called cosmic microwave background (CMB)
• The universe is billions of years old already

  Expansion has not stopped and persists.
• Edwin Hubble's observations

  Galaxies seemed to be moving away from each other with incredible velocity. Galaxies farther away from the Earth move away at a more incredible velocity. Galaxies moving away from us produce a redshift, meaning the wavelength becomes longer, while galaxies moving towards us produce a blueshift or shorter wavelength.
• Doppler Effect


  Thought experiment used to understand how the pitch of a sound changes as the source moves towards or away from the observer.
• Doppler Effect

  1. Siren's pitch lowers as the ambulance approaches

  2. Siren's pitch becomes higher as the ambulance passes
• Wavelength


  Gets longer as the source approaches<|>Gets shorter as the source moves away.
• Nebular Theory

  Theory of the origin of the Solar System
• Development of the Nebular Theory

  1. Proposed and developed by Emanual Swedenborg, Immanuel Kant, Pierre-Simon Laplace, and Victor Safronov

  2. Became the accepted model of the origin of the solar system in the 20th century
• Solar system formation

  Formed from an enormous rotating cloud of dust and gas called the solar nebula nearly 4.6 billion years ago.
• Solar nebula formation

  1. Began to contract and flatten due to gravity

  2. Gravitational energy converted into thermal energy, generating high temperatures

  3. High temperatures and inward pull of gravity led to formation of a proto-Sun

  4. As contraction declined, temperatures began to cool, condensing rock-forming elements

  5. Particles collided and accreted into masses called planetesimals (proto-planets) which eventually formed planets
• Inner planets (terrestrial planets)


  Formed from heavier rock-forming elements condensed due to higher temperatures within the center of the solar system.
• Outer planets (jovian or gaseous planets)


  Formed with small, rocky cores but are primarily composed of ice and gas such as CO2,H2O, NH3, and CH4.