topic 8- space

• What is at the center of our solar system?

  The Sun
• What does heliocentric mean?

  The Sun is at the center
• Name two dwarf planets that orbit the Sun.

  Pluto and Ceres
• What other celestial bodies are found in our solar system?

  Asteroids and comets
• How does our solar system relate to the Milky Way galaxy?

  It is a small part of the Milky Way
• What mnemonic helps remember the order of the planets?

  • My Very Early Morning Jam Sandwich Usually Nauseates
• What are smaller planets primarily made of?

  Rock
• What are larger planets primarily made of?

  Gas
• How do all planets orbit the Sun?

  On the same plane
• Do all planets rotate at the same speed?

  No, they rotate at different speeds
• What can cause a planet to rotate in the opposite direction?

  Past collisions affecting its axis
• Why do larger planets have rings?

  Strong gravitational field attracts debris
• What was the initial model of the solar system?

  The geocentric model
• What did the geocentric model propose?

  Everything orbited the Earth
• What was a key feature of the geocentric model?

  Orbits were perfect circles
• What evidence supported the heliocentric model?

  Mars' retrograde motion
• What happens during Mars' retrograde motion?

  It appears to reverse direction in the sky
• What did Galileo observe that challenged the geocentric model?

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

  They orbit in ellipses
• What causes a planet to change direction as it orbits the Sun?

  The gravitational force from the Sun
• What does the changing velocity of a planet indicate?

  It is constantly accelerating
• What happens if a planet moves closer to the Sun?

  Gravitational attraction increases
• What is the result of increased gravitational attraction?

  Orbital speed of the planet increases
• What is the initial state of a star's life cycle?

  A dust and gas cloud
• What causes the dust and gas cloud to become concentrated?

  Gravitational attraction between particles
• What happens as particles in the cloud get closer together?

  Temperature and pressure increase
• What occurs when pressure in the cloud becomes great enough?

  Fusion of gas/dust particles occurs
• What is produced when hydrogen nuclei fuse together?

  Helium nuclei
• What does fusion create in a star?

  A large amount of energy
• What balances the gravitational collapse of a star?

  The energy released from fusion
• What happens when a star runs out of gas to fuse?

  It collapses
• What occurs if a massive star collapses?

  It produces a supernova
• What remains after a massive star's supernova?

  A neutron star or black hole
• What happens to a normal-sized star after it collapses?

  It produces a planetary nebula
• What remains after a normal-sized star's collapse?

  A white dwarf
• What does red shift indicate about galaxies?

  They are moving away from Earth
• What does the change in distance of galaxies' speed indicate?

  The universe is expanding
• How can the expansion of the universe be visualized?

  As an expanding balloon with galaxies on it
• What happens to the wavelength of light from a galaxy moving away?

  It becomes red-shifted
• What happens to the frequency of light as a galaxy moves away?

  It appears to decrease