Life cycle of stars

• What is the first stage in the life cycle of a star?

  nebula
• What is the second stage in the life cycle of a star?

  protostar
• What is an example of a main sequence star?

  The Sun
• What stage follows the main sequence star in the life cycle of a star?

  Red giant/ Red supergiant
• What causes a protostar to form?

  Gravity pulling dust and gas together
• What happens during the main sequence stage of a star?

  Nuclear fusion balances the force of gravity
• What occurs when hydrogen in the core of a star begins to deplete?

  The star becomes denser and hotter
• How does a star become a red giant?

  When hydrogen in its core is depleted, causing it to expand
• What happens to a small-to-medium-sized star after it becomes a red giant?

  It ejects its outer layers and becomes a white dwarf
• What occurs in the life cycle of a big star after it undergoes fusion to create heavier elements?

  It eventually explodes in a supernova
• What is the term used for the clouds of gases and dust from which stars are formed?

  Nebula
• What happens to a star when it runs out of hydrogen gas?

  It expands and gets colder
• What are the stages in the life cycle of a star similar in size to the Sun?

  1. Main sequence star
  2. Red giant
  3. White dwarf
  4. Black dwarf
• What are the stages in the life cycle of a star much larger than the Sun?

  1. Main sequence star
  2. Red supergiant
  3. Supernova
  4. Neutron star or black hole
• What is the name of the model that places the Earth at the center of the Solar System?

  Geocentric model
• Who proposed the heliocentric model of the Solar System?

  Copernicus
• What did Galileo observe that contradicted the geocentric model?

  The phases of Venus
• What did Johannes Kepler discover about the orbits of planets?

  They are elliptical, not circular
• What is the significance of the red-shift observed in light from distant galaxies?

  It indicates that the Universe is expanding
• What is the cosmic microwave background (CMB) radiation?

  Radiation left over from the moment of creation of the Universe
• What does the Big Bang Theory propose about the origin of the Universe?

  It started about 15 billion years ago with a tremendous explosion
• How does the Steady State Theory differ from the Big Bang Theory?

  The Steady State Theory suggests the Universe has no beginning or end, while the Big Bang Theory posits a specific starting point
• What happens to the core of a massive star after a supernova?

  It can become a neutron star or a black hole
• What is a protostar?

  A concentration of gas and dust that becomes hot enough to cause nuclear fusion
• What is the main source of energy in stars during the main sequence phase?

  Hydrogen fusion
• What is the fate of a star that is similar in size to the Sun after it becomes a red giant?

  It will become a white dwarf
• What is the habitable zone around a star?

  The region where temperatures allow liquid water to exist
• How do gravitational forces contribute to the formation of stars?

  They pull together clouds of dust and gas to form a protostar
• What is the process that releases energy inside a star?

  Nuclear fusion
• What happens to a star after it becomes a red supergiant?

  It explodes in a supernova
• What is the heaviest element formed by fusion in a main sequence star?

  Helium
• How are chemical elements distributed through space?

  Through supernova explosions
• What are the key components of the Solar System?

  • The Sun
  • Orbiting planets
  • Moons
  • Comets
  • Asteroids
  • Meteors
• What are the main differences between a red giant and a red supergiant?

  • Red giant: Star similar in size to the Sun, expands and cools.
  • Red supergiant: Much larger star, expands significantly and eventually explodes as a supernova.
• What are the two main theories regarding the origin of the Universe?

  • Steady State Theory: Universe has no beginning or end, appears unchanged over time.
  • Big Bang Theory: Universe started 15 billion years ago with a massive explosion and is expanding.
• What is the role of gravitational forces in the formation of the Solar System?

  • Gravitational forces pull dust and gas together to form a protostar.
  • The Sun's gravity holds the Solar System together, influencing the orbits of planets and other objects.