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Questions on the Earth in Space

Q8. 'Orbital period' is the scientific term for the time taken for one orbit.

The sketch graph below gives information about some of the planets in the Solar System.

(a) Planet A is shown on the graph above. The orbit of planet A is between Saturn and Neptune. What is the name of planet A?

Uranus

1 mark

(b) Part of the graph is shown in more detail below.

(i) Use a dot to mark the position of the Earth on the graph above as precisely as you can. Label the dot 'Earth'. Explain why you put the dot at this position.

Dot must be placed so that the orbital period is one year

Reason for placing it there: The orbital period of the Earth is one year.

2 marks

(ii) On the same graph, mark with a cross the approximate position of Venus and label it 'Venus'.

The Venus cross can be accepted anywhere between Mercury and Earth

Note that the examiner asks you to label your dot and cross - without the labels the dot and cross may not get a mark! Always do what the examiner says!

1 mark

(c) Asteroids orbit the Sun just like the planets. Information about five asteroids is given in the table below. Which asteroid is the closest to the Sun? Give the reason for your answer.

Name of Asteroid Eugenia Hestia Iris Melpomene Psyche
Orbital period/Earth Years 4.49 4.01 5.51 3.48 5.00

As an orbiting object gets further away from the object it orbits the orbital period increases.

Melpomene has the shortest orbital period so it must be the closest to the Sun.

1 mark

Maximum 5 marks