Lesson 1: Origin of the Universe

Origin of the Universe

What is the Universe?

• Pythagoras = "The all" or "all things"

• Cosmos = "The world"

Observable Universe

The observable universe is the portion we can currently observe.

Structure of the Universe

• Superclusters: Large group of smaller galaxy clusters.

• Clusters: Clumps of dark matter and galaxies held by gravity.

• Galaxy Groups: The smallest groupings of galaxies

• Galaxies: Basic building blocks, moving apart due to expansion

Components of the Universe

The universe is composed almost completely of:

• Dark energy - 71.4% (causes expansion)

• Dark matter - 24% (Invisible/doesn't emit light, has gravity)

• Baryonic matter - 4.6% (Ordinary matter (stars, planets, humans)

Big Bang Theory

• Singularity: (a fireball or a nebula). This singularity expanded rapidly.

• The galaxies divided to form stars, planets, the sun, the moon, and other celestial bodies.

• 1927: Georges Lemaître

  • Belgian cosmologist and Catholic priest (Father of the Big Bang Theory)

  • Proposed the Big Bang Theory

• 1915: Albert Einstein

  • Developed theory of general relativity (10 field equations, predicted that the universe is expanding)

• 1930s: Alexander Friedman - used Einstein's equations to develop/model 2 universe types:

  • Closed Universe: Expands, then collapses

  • Open Universe: Expands foreve

• 1924: Edwin Hubble - Discovered that galaxies' moving apart

  • He was the first to describe the redshift

  • Redshift: Light from objects moving away gets stretched and looks redder. The faster they move, the redder the light.

Evidence for the Big Bang Theory

1. Redshift

2. Abundance of Hydrogen, Helium, and Lithium

3. Ongoing/Continuous Expansion

• Age of Universe: 13.82 billion years (measured by Max Karl Ernst Ludwig Planck, a German theoretical physicist)

Non-Scientific Origin of the Universe

Ancient Beliefs

• Ancient Egyptians: Believed world arose from an infinite sea at the first rising of the sun.

• Kuba (Central Africa) – Creator god Mbombo vomited stars, sun, and moon

• India: gods sacrificed Purusha, the primal man, and his body parts became parts of the universe:

  • Head → Sky

  • Feet → Earth

  • Eyes → Sun

  • Mind → Moon

• Monotheistic religions: Judaism, Christianity, and Islam believe a Supreme Being created the universe

Creationist Theory

• God created the universe.

Steady State Theory

• Proposed in 1948 by Bondi, Gold, and Hoyle

• Universe has always existed in the same state

• No beginning, no end — constant creation of matter