The solar system (age 11+)

Science · Space Systems & Earth's History · ages 11-12

Name ______________________ Date ____________

Which planet is famous for the bright rings you can see through a telescope?
- Mars
- Saturn
- Mercury
Which of these is NOT usually round in shape?
- Asteroid
- Dwarf planet
- Planet
A planet that orbits far from the Sun takes longer to complete one orbit than a planet that orbits close to the Sun.
Circle one: True False
Which planet would you expect to have day and night patterns very different from Earth's, because it spins almost on its side?
- Uranus
- Neptune
- Jupiter
What is the biggest difference between a comet and an asteroid?
- A comet never orbits the Sun, but an asteroid does
- A comet is always bigger than a planet
- A comet is made of ice and dust and grows a tail near the Sun; an asteroid is rocky and has no tail
Look at the chart. About how many Earth years does Jupiter take to complete one orbit of the Sun?
Answer: ______________
A newly discovered object takes about 250 Earth years to complete one orbit of the Sun. Based on the pattern between distance and orbital period, where would you expect to find it?
- Close to the Sun, near Mercury
- Exactly between Earth and Mars
- Far beyond Neptune
Leo says, 'Pluto is a planet because it's round and orbits the Sun.' What is wrong with his reasoning?
- Pluto is not round
- Pluto has not cleared other objects out of its orbital path, so it counts as a dwarf planet
- Pluto does not orbit the Sun at all

Answer key

For grown-ups. Fold this page away before handing over the rest.

Saturn · Saturn's rings are made of ice and rock, and they make it one of the easiest planets to recognize.
Asteroid · Planets and dwarf planets are round because their own gravity pulls them into a sphere. Most asteroids are too small and lumpy for that to happen.
True · A farther planet has a much bigger circle to travel, so its year lasts longer.
Uranus · Uranus is tipped almost 90 degrees, so its poles get very long stretches of light and dark instead of a normal day-night cycle.
A comet is made of ice and dust and grows a tail near the Sun; an asteroid is rocky and has no tail · Comets are icy, so heat from the Sun turns some of their ice to gas and forms a tail. Asteroids are rocky and stay tail-less.
12 · Jupiter sits much farther from the Sun than Earth, so its orbit takes about 12 Earth years, far longer than Earth's single year.
Far beyond Neptune · Longer orbital periods belong to objects farther from the Sun. Since Neptune's orbit takes about 165 years, an object taking 250 years must sit even farther out.
Pluto has not cleared other objects out of its orbital path, so it counts as a dwarf planet · Being round and orbiting the Sun is not enough. A planet must also have cleared its neighborhood of other objects, and Pluto has not.