es(wk1&2)part I

• the universe is always expanding in a constant average density and mass.

  Steady State Theory
• Father of the Big Bang

  George Lemaitre
• formulated in 1927 & called it hypothesis of the primeval atom; the universe began from a single primordial atom.


  Big Bang Theory
• supports the Big Bang Theory

  Cosmic Inflation Theory
• (4.6 billion years ago) solar system was formed from a rotating gas cloud/nebula of extremely hot gas – gas cooled – nebula

  shrinks – rotate faster – forming a disc-like shape == the central hot region = the sun; materials surrounding it = the planets.

  Nebular Hypothesis
• developer of nebular hypothesis

  Immanuel Kant & Pierre-Simon Laplace
• (5 billion years ago) cloud of gas (10 billion km in diameter) & dust rotated slowly – cloud shrank

  under its own gravitation – collapsed by the explosion of a passing star.

  Planetesimal Theory
• thin layer of gasses surrounding Earth; insulates the Earth from extreme temperatures; blocks UV rays.

  Atmosphere
• solid, outermost layers of Earth’s structure; the brittle upper portion of mantle & crust.

  Biosphere
• Earth’s liquid water; covers 70% of Earth’s surface; home for many plants and animals.

  Hydrosphere
• any naturally occurring solid substance w/ a definite chemical composition.

  Mineral