GEO 11

• Geology - geos (earth)+ logos (discourse/study)
• Geology - the science that pursues an understanding of the Earth, its origin and history, the processes that shaped it, and the resources that could be obtained from it
• Geology - scientific study of the earth's materials, processes, and its history
• Orogeny - mountain-building process
• Catastrophism - proposed by Baron Georges Cuvier
• Catastrophism - sudden, worldwide catastrophes are the agents of change that alter the physical features of the Earth over time and the latter remains unchanged in between these periods of upheavals
• Catastrophism - widely accepted by theologians in the early 1800s due to similarity with Biblical events such as the Great Flood
• James Hutton - father of geology
• Uniformitarianism - early idea was proposed by James Hutton and refined by John Playfair
• Uniformitarianism - "The present is the key to the past."
• Uniformitarianism - the Earth is continuously modified by geologic processes that have always operated throughout time (albeit different time rates).
• Uniformitarianism - accepting this theory would mean that the world has been around for a very long time as opposed to the estimated made at that time
• Big Bang theory - formation of the universe
• Nebular theory - formation of the solar system
• Big Bang theory - proposed by Georges Lemaitre in the 1920s
• Big Bang theory - contends that the Universe originated from an incomprehensively large cosmic “explosion” (origin unknown) that hurled matter in all directions at incredible speed 13.7 billion years ago
• During this time (big bang), the universe was also thought to be opaque.
• Supernovae explosion - the very energetic explosion of massive stars created elements heavier than iron
• Three main evidence supporting the Big Bang: abundance of primordial elements: primarily hydrogen and helium (and other light elements), Hubble's Law, and cosmic microwave background radiation (CMB)
• Hubble's Law - galaxies seem to be moving away from us at speeds proportional to their distance
• Red shift - refers to the shift of light towards longer wavelengths, often observed in the spectra of distant celestial objects, and is a key indicator of their motion away from an observer; it is a crucial piece of evidence supporting the expansion of the universe. It is a consequence of the Doppler Effect
• Red shift - how we see waves when the object that is creating the waves is moving toward us or away from us
• Cosmic microwave background radiation (CMB) - remnant heat of the universe, a 2.725 Kelvin signature
• Arno Penzias and Robert Wilson - accidentally discovered CMB in 1965
• Cosmic microwave background radiation - translates to the very small density differences of matter in the early universe and is considered as the snapshot of the oldest (microwave) light in the universe
• CMB - remnant radiation
• CMB - snapshot of the oldest microwave light
• Main basis in determining the age of the universe - oldest objects in the universe and measuring speed of its expansion
• Population III stars and globular clusters - oldest objects in the universe that gives an age limit of 11-18 billion years
• Limitations of the Big Bang theory

  • What was present before the universe?
  • Will the universe end?
  • How will it cease to exist?
• Steady-state theory - new matter is continuously created as the Universe expands
• Cosmological principle - the observable universe is basically the same in any time as well as any place
• Alternative theories - Steady-state theory and Divine Intervention or Theological theory
• Stages in star lifetime - (1) yellow star, (2) red giant, (3) red supergiant, (4) massive red supergiant, (5) supernova
• Immanuel Kant and Pierre Simon de Laplace - proposed the nebular hypothesis in the 18th century
• Nebular hypothesis - suggests that the solar system originated from a single rotating cloud if gas and dust which contracted due to gravity starting 4.6 bya
• Solar nebula - single rotating cloud of gas and dust
• Nebula - collection of clouds of dust (very tiny grains of minerals, ice crystals, and organic particles) and gas (mostly hydrogen and helium)
• The rotating gas-dust cloud began to contract due to gravity.
• Accretion disk - flattened astronomical objects made of rapidly rotating gas which slowly spirals onto a central gravitating body