L1 | ORIGIN OF THE UNIVERSE

• BIG BANG THEORY

  • Began (universe) from a hot and infinitely dense point, which is similar to supercharged black hole (singularity theory)
  • Happened 13.7 billion years ago, the singularity violently exploded 
  • All matter, energy, time, and space were created
• SINGULARITY THEORY

  • Extremely high energy and temperature that led to the explosion
  • Explosion leads to expansion
  • Universe is believed to be form a single point of energy and exploded because of too much energy
• STAGES AFTER BIG BANG

  1. radiation era
  2. matter era
• 4 FORCES OF NATURE:

  1. gravity
  2. strong nuclear
  3. weak
  4. electromagnetic
• • LARGE STAR - shorter life span, need larger source of energy
  • SMALL STAR - longer life span, uses own energy
• 2 EARLY HYPOTHESES:

  1. catastrophic hypothesis
  2. evolutionary hypothesis
• CATASTROPHIC HYPOTHESIS

  • E.g. passing star hypothesis
  • Star passing the sun closely tore material out of the sun, from which planets could form (no longer considered)
  • Predict: Only few stars should have planets!
• EVOLUTIONARY HYPOTHESIS

  • E.g. Laplace’s nebular hypothesis
  • Rings of material separate from the spinning cloud, carrying away angular momentum of the cloud →  cloud could contract further (forming the sun) 
  • Predict: Most stars should have planets!
• SOLAR NEBULA HYPOTHESIS

  • Basis of modern theory of planet formation. 
  • Planets form at the same time from the same cloud as the star. 
  • Planet formation sites observed today as dust disks of T Tauri stars. 
  • The Sun and our Solar system formed 4.6 billion years ago.
• PLANETARY ORBIT

  • All planets in almost circular (elliptical) orbits around the Sun in approximately the same plane (ecliptic).
  • Orbit generally inclined by no more than 3.4 degrees except mercury (7 degrees), and pluto (17.2 degrees)
• 2 KINDS OF PLANET

  1. terrestrial (earth-like) planets
  2. jovian (jupiter-like) planets
• TERRESTRIAL (EARTH-LIKE) PLANETS:

  • Mercury, Venus, Earth, Mars 
  • small, rocky, and have a solid or rocky crust
  • High density 
  • Craters 
  • Common throughout the solar system
  • From the debris of outer space.
• JOVIAN (JUPITER-LIKE) PLANETS:

  • Jupiter, Saturn, Uranus, Neptune
  • large, gaseous, and have fluid crusts
  • all have rings (but saturn’s only visible)
  • Low density
  • Craters not seen here because they don't have a solid surface
• SPACE DEBRIS

  • Planets orbit the sun so does small bodies: asteroids, comets, meteoroids
• TERRESTRIAL PLANETS

  1. mercury
  2. venus
  3. mars
  4. earth
• JOVIAN PLANETS

  1. jupiter
  2. saturn
  3. uranus
  4. neptune
• COMETS

  • with tail
  • Icy nucleus, which evaporates and gets blown into space by solar wind pressure.
• METEOROIDS

  • Small dust grains throughout the solar system 
  • If they collide with Earth, they evaporate in the atmosphere. 
  • Visible as streaks of light : meteors.
• WHAT MAKES THE EARTH HABITABLE?

  • Earth's Location
  • Our sun is a stable & long-lasting
  • Just the right distance from the sun
  • Big moon to stabilize our axial wobble
  • Right stuff to host a dynamic core
  • Ozone Layer to block harmful rays
• EARTH SYSTEM

  • a set of all matter both living and nonliving, energy, and processes within Earth's boundary.
• SUBSYSTEM

  • a self-contained system within a larger system
• EARTH'S SUBSYSTEMS:

  1. biosphere
  2. atmosphere
  3. hydrosphere
  4. geosphere
• BIOSPHERE

  • layer of the Earth where life exists
  • "Bios," = life
  • contains all living things on earth
  • plants, animals, microbes, humans, insects, and many other life forms
  • The biosphere maintains ecosystems.
• ATMOSPHERE

  • gaseous envelope surrounding the Earth
  • "atmos," = air
  • contains water vapor and other gasses which help to moderate our daily temperatures
  • protection from meteors by burning it up before hitting the Earth’s surface.
• HYDROSPHERE

  • composed of water surrounding the earth's surface
  • "hydro," - water
  • provides living organisms with water that:
  • breaks down food molecules, 
  • generate energy during respiration process and 
  • regulates metabolism
• GEOSPHERE

  • solid portion of the earth
  • "geo," -  ground
  • covers Earth’s interior composed of rocks, minerals, and landforms
  • Allows occurrence of geologic events
  • Develops a layer of soil with nutrients