Cosmology: The Origin of the Universe

Cosmology Overview

• Cosmology is a branch of astronomy studying the origin and evolution of the universe.
• The universe encompasses all space, time, matter, and energy.

Composition of the Universe

• Baryonic matter: 4.6%, includes protons, neutrons, and electrons forming atoms, planets, stars, and galaxies.
• Dark matter: 24%, has gravitational effects but does not emit light.
• Dark energy: 71.4%, an anti-gravity force causing the universe's expansion.

Elements in the Universe

• Hydrogen and helium: Most abundant elements.
• Stars: Luminous gas balls primarily composed of hydrogen and helium.
• Galaxies: Clusters of billions of stars; superclusters consist of multiple galaxies.
• Planets: Orbiting bodies in the universe.
• Comets: Small bodies that vaporize in sunlight, forming distinct atmospheres and tails.
• Asteroids: Inactive rocky bodies orbiting the Sun.
• Meteoroids: Small particles from comets or asteroids.
• Meteor: Light phenomenon from a meteoroid entering Earth's atmosphere, often referred to as a shooting star.
• Meteorite: A meteoroid that survives atmospheric entry and lands on Earth.

Age of the Universe

• Estimated to be 13.8 billion years old based on observations of ancient stars and cosmic expansion dynamics.

Methuselah Star

• Located 200 light years away in the constellation Libra.
• Estimated age of approximately 14.46 billion years.

Expansion of the Universe

• Hubble's Law describes the relationship between distances and velocities of remote galaxies, indicating the universe's expansion.

Origin Theories

• Non-Scientific Perspectives: Various cultures, such as the Ancient Egyptians and the Kuba people, posited mythological stories about creation.
• Scientific Theories:
  • Steady State Theory: Suggests continuous creation of matter while the universe expands, maintaining constant density.
  • Big Bang Theory: Accepted theory positing that the universe originated from a hot, dense state 13.8 billion years ago, experiencing rapid expansion and cooling.

Stages of Big Bang Evolution

• Radiation Era: Dominance of radiation during initial universe phases.

  • Plank Epoch: Immediately after the Big Bang; only energy existed.
  • Grand Unification Epoch: Strong nuclear force separates from gravity.
  • Inflationary Epoch: Rapid universe expansion allowing formation of particles.
  • Electroweak Epoch: Separation of electroweak forces.
  • Quark and Hadron Epochs: Formation of protons and neutrons occurs as temperatures decrease.

• Matter Era: Begins when conditions allow for atomic formation.

  • Atomic Epoch: Formation of the first stable atoms, primarily hydrogen, and helium.
  • Galactic Epoch: Formation of galaxies from atomic clouds.
  • Stellar Epoch: Formation of stars and further cosmic evolution.

Evidence for Big Bang

• Redshift: Indicates how far away distant objects are; light stretching occurs for objects moving away, discovered by Edwin Hubble.
• Cosmic Microwave Background Radiation: Released about 380,000 years post-Big Bang; remnants discovered by Arno Penzias and Robert Wilson.

Alternative Universe Theories

• Big Crunch Theory: Proposes that at maximum expansion, matter collapses back to singularity (proposed by Alexander Friedmann).
• Oscillating Theory: Suggests continual expansion and contraction of the universe, cycling between these states.

Explore the fascinating field of cosmology and learn about the origin and evolution of the universe. This quiz delves into the composition of the universe, including baryonic matter, dark matter, and dark energy. Test your knowledge on the fundamental concepts that define our cosmos.