Theories of the Universe - CM 1

Theories of the Universe

• Anaxagoras proposed a primordial universe concept.
• Leucippus and Democritus introduced atomic theory, positing that everything is composed of tiny, indivisible atoms.
• Sir Isaac Newton proposed the steady state Infinite universe concept.
• Albert Einstein developed static and Big Bang theories.
• Fred Hoyle coined the term "Big Bang" to describe the universe's origin.
• Hoyle, Thomas Gold, and Hermann Bondi formulated the Steady State Theory, asserting that the universe is eternal and unchanging despite expansion.
• Paul Steinhardt and Neil Turok advanced string theory, addressing gaps in the Big Bang theory.
• Alan Guth introduced the theory of inflation, explaining rapid expansion post-Big Bang.
• Andrei Linde proposed the multiverse theory, suggesting infinite universes continually creating each other.

Models of the Solar System

• Immanuel Kant supported a geocentric model, placing Earth at the universe's center.
• Nicolaus Copernicus proposed the heliocentric model, with the sun at the center of the solar system.

Theories of the Solar System Origin

• Kant and Pierre Simon Laplace presented the nebular hypothesis, suggesting the solar system formed from a gaseous nebula.
• Thomas Chrowder Chamberlin and Forest Ray Moulton introduced the planetesimal hypothesis, where a close star interaction led to ejection of materials.
• James Hopwood and Harold Jeffrey developed the tidal theory, hypothesizing that tidal forces from a star collision created the solar system.
• Gerard Kuiper and Carl von Weizsäcker introduced the protoplanet theory, enhancing the nebular hypothesis with modern insights.

Universe Definition

• The universe encompasses all existence, including stars, galaxies, and all matter.

Galaxy Definition

• A galaxy is a massive system of stars, gas, and dust held together by gravity.

Types of Planets

• Terrestrial planets include Mercury, Venus, Earth, and Mars (MVEM).
• Jovian planets include Jupiter, Saturn, Uranus, and Neptune (JSUN).

Cosmological Concepts

• Genesis describes creation, including light, sky, and living beings over six days.
• Rigveda depicts an oscillating universe birthed from a "cosmic egg."
• Primordial relates to universally existing ingredients in fragments.
• Atomic theory emphasizes inseparable and indestructible atomic components.

Additional Theories and Models

• Stoic view likens the universe to a living body, suggesting the interconnectedness of all parts.
• Steady-State Infinite posits uniform matter distribution and gravitational stability.
• Einstein's static universe was abandoned as it neither expanded nor contracted.
• Big Bang Theory posits a singularity explosion leading to cosmic formation, supported by redshift, cosmic microwave background radiation, and light element abundance.
• String theory seeks to bridge gaps in Big Bang explanations.
• The theory of inflation describes rapid post-Big Bang development.
• Multiverse theory proposes creation of multiple, continuously inflating universes.

Earth's Subsystems

• Four subsystems include the geosphere, hydrosphere, atmosphere, and biosphere.

Geosphere Composition

• Composed of three layers:
  • Crust: Less dense surface layer.
  • Mantle: Rocky layer with three sub-layers:
    • Lithosphere: Upper rigid region.
    • Asthenosphere: Semi-viscous layer below lithosphere.
    • Mesosphere: Lower mantle, hotter with high viscosity.
  • Core: Dense metallic innermost layer.

Hydrosphere Characteristics

• Represents Earth's water, covering 71% of the planet, with 97.5% of that being oceanic.
• Includes cryosphere (permanently frozen components).
• Atmosphere comprises 78% nitrogen, 21% oxygen, and 0.10% other trace gases.