What is a solar system?
A star with planets and other objects that orbit it.
What is the name of our solar system’s star?
The Sun.
What objects orbit the Sun in the solar system?
Planets, dwarf planets, asteroids and comets.
What is a planet?
A large object that orbits a star.
What are the four inner planets of the solar system?
Mercury, Venus, Earth and Mars.
What are the four outer planets of the solar system?
Jupiter, Saturn, Uranus and Neptune.
What are the outer planets mainly made of?
Gas and ice.
What lies between Mars and Jupiter?
The asteroid belt.
What are asteroids?
Small rocky objects that orbit the Sun.
What are comets made of?
Ice, dust and rock.
What happens to a comet when it approaches the Sun?
Ice vaporises forming a tail.
What force keeps planets in orbit around the Sun?
Gravitational force.
What is a natural satellite?
An object that orbits a planet.
What is the natural satellite of Earth?
The Moon.
What is a galaxy?
A collection of billions of stars held together by gravity.
What galaxy is the Solar System in?
The Milky Way.
What is the universe?
Everything that exists including all galaxies.
What is the Big Bang theory?
The idea that the universe began from a very hot dense state and has been expanding.
What evidence supports the Big Bang theory?
Red-shift of galaxies and cosmic microwave background radiation.
What is red-shift?
The increase in wavelength of light from an object moving away from the observer.
What causes red-shift in light from distant galaxies?
The galaxies are moving away as the universe expands.
What does a larger red-shift indicate?
The galaxy is moving away faster.
What does red-shift suggest about the universe?
The universe is expanding.
What is the Doppler effect?
The change in frequency or wavelength of a wave due to motion between source and observer.
