Formation of the Universe and the Solar System

• Cosmogeny


  The understanding of the origin, evolution, structure, and fate of the universe
• Atom


  Smallest unit of matter
• Matter


  Anything with mass and occupies space
• Galaxy


  • Cluster of billions of stars, planets, asteroids and other bodies in the planetary system
  • Empty spaces in between these clusters
• Milky Way


  • A large spiral galaxy in which the sun and planets are part of
  • A large group of stars, gas, and dust held together by gravity
• Solar System


  • Consists of the sun, planets, satellites, asteroids, and comets
  • These bodies are held together by its attraction towards the sun and revolve around it
  • Located in the Milky Way
  • Estimated to be 4.5 billion years old based on radioactive dating of meteorites
• Age of the Universe

  • The universe is 13.8 billion years old
  • The diameter of the universe is possibly infinite but it should be at least 93 billion light years or more
  • 1 light year = 9.4607 x 10^12 km
  • The age of the universe is estimated by looking at the oldest stars
  • The farther away an object is, the longer it has taken light to travel across space from the object to Earth
• Calculating the age of the universe

  1. Velocity = Distance / Time

  2. Velocity: rate of expansion of the universe

  3. Distance: estimated diameter

  4. Time: age of the universe
• Big Bang Theory


  • The prevailing cosmological model of the universe
  • Around 13.8 billion years ago, the universe expanded from a tiny, dense, and hot mass of energy (singularity) to its present site and much cooler state
  • It created incredible mixtures of energy and sub-atomic particles (the first matter in the universe) which are protons, neutrons, and electrons
• Singularity


  • An instant where all matter and energy in the universe was concentrated into a single point and that the density and energy of what would become the universe would be arbitrarily very large and infinite
  • A mathematics concept that has no equivalent in the physical world
• The Big Bang is not an explosion but rather a simultaneous expansion of space everywhere
• Origins of the Big Bang

  • Georges Henri Joseph Édouard Lemaître (1927) - Belgian catholic priest suggested the big bang theory in the 1920s, hypothesized that the universe began from a single primordial atom, introduced the theory as "Primeval atom hypothesis"
  • Fred Hoyle coined the term "big bang"
• The expansion of the Universe

  Galaxies seem to be moving away from us at speeds proportional to their distance
• Redshift


  • Light from distant galaxies is shifted to red at the end of the electromagnetic spectrum
  • The longer the travel, the more it gets redshifted
  • The further away the galaxy, the greater the redshift of its spectral lines (Hubble's law)
• Doppler Effect


  Volume increases as the object moves towards the observer and decreases as it moves away
• Spectograph/Spectroscope


  Gathers light from the object of interest which is then separated in the colors of the spectrum
• Cosmic Microwave Background (CMB) Radiation is a remnant radiation left over from the Big Bang
• The big bang theory predicts that light elements like hydrogen and helium could have been fused from protons and neutrons combined in the first few minutes after the big bang forming the first atoms
• The Big Crunch


  • Possible scenario for the possible fate of the universe
  • The expansion of space will reverse and the universe will collapse
  • Expansion will reach a certain size and then shrink
  • It will draw inward and collapse as it shrinks
  • The universe will expand and contract and the process will repeat indefinitely
• Arrangement of the Solar System

  • Sun
  • Mercury
  • Venus
  • Earth
  • Mars
  • Jupiter
  • Saturn
  • Uranus
  • Neptune
• Mercury


  • Closest to the sun
  • No natural satellites
  • Revolution: 88 days
  • Distance: 3.6 x 10^7 miles
  • Diameter: 3,112 miles
• Venus


  • Second planet from the sun
  • No natural satellites
  • Revolution: 225 days
  • Distance: 6.72 x10^7 miles
  • Diameter: 7,584 miles
• Earth


  • Third planet from the sun
  • One natural satellite (Luna/Moon)
  • Revolution: 365 days
  • Distance: 930.09 x 10^5
  • Diameter: 7,927 miles
• Mars


  • The fourth planet from the sun
  • Dusty, cold, desert with a thin atmosphere
  • Has 2 natural satellites
  • Revolution: 687 days
  • Rotation: 24 hours and 37 mins
  • Distance: 14.16 x 10^7
  • Diameter: 4, 220 miles
• Jupiter


  • Fifth planet from the sun
  • Biggest planet
  • Has 12 natural satellites
  • Rotation: 9 hours and 50 mins
  • Revolution: 11 ¾ earth years
  • Distance: 4.85 x 10^8
  • Diameter: 86,800 miles
• Saturn


  • Sixth planet from the sun
  • Second largest planet
  • Has thousands of ringlets
  • Has 9 natural satellites
  • Rotation: 10 hours 2 mins
  • Revolution: 29 ½ earth years
  • Distance: 8.9 x 10^8 miles
  • Diameter: 75, 100 miles
• Uranus


  • "Sideways planet" as it rotates on its side by 98 degrees
  • A ringed planet
  • Has 28 natural satellites
  • Rotation: 10 hours 45 mins
  • Revolution: 84 earth years
  • Distance: 1.78 x 10^9 miles
  • Diameter: 30, 900 miles
• Neptune


  • Eighth and farthest planet from the sun
  • Dark, cold, ice giant
  • Has 16 natural satellites
  • Rotation: 15 hours 48 mins
  • Revolution: 165 earth years
  • Distance: 3.67x 10^9 miles
  • Diameter: 33,000 miles
• Kuiper Belt


  • Doughnut-shaped ring
  • Icy objects that surround the sun
  • 30-55 au from Neptune
  • One astronomical unit (or AU) is the distance from the Sun to Earth, or about 93 million miles (150 million kilometers)
• Oort Cloud


  • Spherical layer of icy objects surrounding the sun
  • 2,000 to 100,00 au from the sun
• Dwarf Planet


  A celestial body that orbits the sun, has enough mass to assume a nearly round shape, but has not cleared the neighborhood around its orbit and is not a moon
• Terms


  • Nebula - any large cloud of interstellar gas and dust
  • Accretion - dust particles stick together to form larger particles
  • Condensation - conversion of vapor or gas to a liquid or solid state caused by a reduce in the temperature
  • Planet - celestial body moving in an elliptical orbit around a star
  • Planetesimals - minute planet; a body that could or did come together with many others under gravitation to form a planet
  • Protoplanets - large body of matter in orbit around the sun or star and thought to be developing into a planet
  • Meteoroid - small rocky piece of matter that is smaller than a kilometer
  • Asteroid - larger chunks of rocky matter between orbits of Mars and Jupiter is called the asteroid belt
  • Comet - body that appears as a fuzzy head surrounding a bright nucleus
  • Natural Satellites - bodies orbiting a planet
  • Rotation - spinning on its axis
  • Revolution - going around another object in an orbit or elliptical course
• Large Scale Features of the Solar System

  • Much of its mass is concentrated at the center (sun) while the momentum is held by the outer disks (planets)
  • All planets revolve around the sun
  • Period of revolution increase along with the increasing distance from the sun; the innermost revolves the fastest and the outermost revolves the slowest
  • Orbits are elliptical and in the same plane
• Small Scale Features of the Solar System

  • Rotates prograde (counterclockwise)
  • Inner planets are made up of materials with high melting points such as silicates, iron, nickel
  • Rotate slower and have thin or no atmosphere, higher densities, lower contents of hydrogen, helium, and noble gases
  • Outer planets are called "gas giants" because of the dominance of gas and their large size
  • Rotate faster, have thick atmosphere, lower densities, fluid interiors rich in hydrogen, helium, and ices (water, ammonia, methane)
• Hypotheses on the Origin of the Solar System

  • Nebular Hypothesis - Proposed that planets form in the rotating disks of gas and dust (nebula) around a star
  • Encounter Hypothesis - Proposed that a star much bigger than the sun passed by the sun drawing gaseous filaments from both out which planetesimals are formed
  • Accretion Theory - Proposed that the sun passed through a dense interstellar cloud and emerged with a dusty, gaseous envelope that eventually became the planets
  • Capture Theory - Proposed that the sun drags from a near proto-planet a filament of material which becomes the planets
  • Protoplanet Hypothesis - Proposed that a slowly rotating gas and dust cloud dominated by hydrogen and helium starts contraction due to gravity, with most of the mass moving to the center to become the protosun and the remaining materials forming a disc that will eventually become the planets