Topic 7-Astronomy

• What is the formula for weight in physics?

  $W =$$mg$
• What does the variable 'W' represent in the formula $W =$$mg$?


  Weight in Newtons (N)
• How does the value of 'g' affect the weight of an object?

  A greater 'g' increases the object's weight
• What causes a higher value of 'g' on a planet?

  A greater mass of the planet
• Why do larger planets have a stronger gravitational pull?

  They have more mass
• What are the main components of our Solar System?

  • The Sun
  • Eight planets
  • Natural satellites
  • Dwarf planets
  • Asteroids and comets
• List the eight planets in our Solar System.

  Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
• What is the mnemonic to remember the order of the planets?

  My Very Early Morning Jam Sandwich Usually Nauseates
• How do smaller planets differ from larger planets in composition?

  Smaller planets are primarily rocky
• What is the orbital plane of the planets in our Solar System?

  All planets orbit the Sun on the same plane
• What happens to the rotation of planets?

  All planets rotate at different speeds
• Why do some planets rotate in the opposite direction?

  Due to past collisions affecting their axis
• Why do larger planets have rings?

  Their strong gravitational field attracts debris
• What were the two main models of the Solar System?

  1. Geocentric model: Earth at the center
  2. Heliocentric model: Sun at the center
• What evidence supported the heliocentric model?

  Mars' retrograde motion observation
• What did Galileo observe that challenged the geocentric model?

  Moons orbiting Jupiter
• What did Kepler discover about planetary orbits?

  Planets orbit in ellipses, not circles
• What causes a planet to change direction while orbiting the sun?

  The gravitational force from the sun
• What remains constant as a planet orbits the sun?

  The speed of the planet
• What happens to the velocity of a planet as it orbits the sun?

  The velocity is always changing
• What happens to a planet's orbital speed if it moves closer to the sun?

  The orbital speed increases
• What does red shift indicate about galaxies?

  They are moving away from Earth
• What does the emission spectrum show?

  Different wavelengths emitted from a star
• What does a red shift in the emission spectrum indicate?

  Galaxies are moving away from us
• How does the red shift relate to the expanding universe?

  It increases with distance from Earth
• What is the analogy used to explain the expanding universe?

  • An un-stretched balloon
  • Galaxies on the surface expand as the balloon inflates
• What happens to the wavelength of light from a galaxy as it moves away?

  It appears red-shifted
• What happens to the frequency of light as the wavelength increases?

  Frequency decreases
• What evidence supports the Big Bang theory?

  • Red Shift: Indicates universe is expanding
  • CMB: Cosmic Microwave Background radiation
• What is Cosmic Microwave Background radiation (CMB)?

  Radiation from the early hot universe
• What does the presence of CMB indicate about the universe?

  The universe has cooled and expanded
• What does the Steady State Theory propose about the universe?

  Constant density of matter as it expands
• What evidence contradicts the Steady State Theory?

  Different stars present at different eras
• Why does the Steady State Theory not account for CMB?

  It does not explain the universe's cooling
• What is the life cycle of a star?

  1. Dust and gas cloud forms nebulae
  2. Gravitational attraction causes fusion
  3. Star forms and remains stable
  4. Star runs out of gas and collapses
  5. Massive stars produce supernova; normal stars become white dwarfs

  
• What is the role of gravitational attraction in star formation?

  It draws gas and dust particles together
• What happens to the temperature and pressure in a star-forming cloud?

  They increase as particles get closer
• What occurs when pressure in a star-forming cloud becomes very high?

  Fusion of gas/dust particles occurs
• What is the result of fusion in a star?

  It creates a large amount of energy
• What happens when a star runs out of gas to fuse?

  It collapses due to lack of equilibrium