Exploring Pluto and the Kuiper Belt

What significant advancement in the 1600s allowed astronomers to study more distant celestial objects?

• The discovery of electricity

• The invention of the microscope

• The development of the steam engine

• The invention of the telescope

Who discovered Pluto and in what year?

• Galileo Galilei in 1610

• Isaac Newton in 1687

• Clyde Tombaugh in 1930

• Albert Einstein in 1905

How many moons does Pluto have?

• Seven

• Five

• Three

• One

What is the main reason Pluto was reclassified as a dwarf planet?

• It does not orbit the Sun

• It is not massive enough to be round

• It is too far from the Sun

• It shares its orbit with other objects

Which of the following is NOT a criterion for an object to be classified as a planet?

• It must clear its orbit of other debris

• It must orbit the Sun

• It must be massive enough to be nearly round

• It must have a large number of moons