Space

• What is at the center of the Solar System?

  The Sun
• How many planets orbit the Sun?

  Eight planets
• What are the main components of the Solar System?

  • Planets
  • Dwarf planets
  • Moons
  • Artificial satellites
  • Asteroids
  • Comets
• Name the eight planets in order from the Sun outwards.

  Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
• What defines a dwarf planet?

  Planet-like objects not big enough to be planets
• What is a moon?

  A natural satellite orbiting a planet
• What are artificial satellites?

  Man-made objects orbiting Earth
• What are asteroids primarily made of?

  Rock and metals
• How do comets differ from asteroids?

  Comets are made of ice and dust
• What is the shape of a comet's orbit?

  Highly elliptical
• What force creates orbits in the Solar System?

  Gravity
• What happens to an object in a circular orbit at constant speed?

  It is constantly accelerating
• What is the centripetal force?

  Force acting towards the center of a circle
• What does the gravitational force do to an orbiting object?

  Causes it to change direction
• How does gravitational force depend on mass?

  Larger mass means a stronger gravitational field
• How does gravitational force vary with distance?

  Stronger when closer to a star or planet
• What happens to the speed needed to remain in orbit as you get closer to a star?

  You need to go faster
• What happens to the radius of an orbit if the speed of an object changes?

  The radius must change too
• What did ancient Greeks believe about the Solar System?

  Earth was the center of the Solar System
• What is the geocentric model?

  Earth-centered model of the Solar System
• What is the heliocentric model?

  Sun-centered model of the Solar System
• What evidence did Galileo provide for the heliocentric model?

  Moons around Jupiter
• How did technological advances affect the heliocentric model?

  Increased evidence supporting the model
• What is the current model of the Solar System regarding orbits?

  Orbits are elliptical, not circular
• What does the Steady State theory propose about the Universe?

  The Universe has always existed as it is now
• What happens to matter in the Steady State theory as the Universe expands?

  New matter is constantly being created
• What does the Big Bang theory state about the Universe's beginning?

  The Universe started with an explosion
• How old is the Universe according to the Big Bang theory?

  Around 13.8 billion years
• What does red-shift indicate about galaxies?

  They are moving away from each other
• What is cosmic microwave background radiation (CMB radiation)?

  Low frequency radiation from all directions
• Why does CMB radiation support the Big Bang model?

  It shows the Universe had a beginning
• How does red-shift relate to the expansion of the Universe?

  It indicates galaxies are moving away faster
• What is the relationship between distance and red-shift?

  More distant galaxies have greater red-shifts
• What does the Doppler effect explain in terms of red-shift?

  Frequency decreases as objects move away
• What does the absorption spectrum show?

  Specific patterns of dark lines for elements
• How does the absorption spectrum change for distant galaxies?

  Dark lines are red-shifted
• What does the observed increase in wavelength from distant galaxies indicate?

  The Universe is expanding
• What is the significance of the Big Bang theory in astronomy?

  It explains the origin of the Universe
• What is the relationship between gravitational field strength and distance?

  It decreases with increasing distance
• What happens to the gravitational force as mass increases?

  The gravitational force increases