Questions on the Earth in Space
Q7.
(a) An artificial satellite can sometimes be seen in the night sky - looking like a bright star. We have put them into orbit. They are not natural.
Some satellites appear to stay still - always being at the same position in the sky, but in fact they are moving in an orbit so that as the Earth spins on its axis they are always above the same point.
(i) What is the name given to satellites that appear to be stationary above one point on the Earth?
Geostationary satellites 
(ii) What is the orbital period of such a satellite (The time it takes for the satellite to orbit the Earth once?
24 hours
2 marks
(b) Satellites look like stars - sometimes slowly moving across the sky. We can see stars because they are light sources. They give out their own light. Satellites do not give out their own light. Explain why satellites can be seen in the clear night sky even through they do not give out their own light.
They reflect or scatter light from the Sun.
Accept 'light reflects off the satellite' but not 'light reflects on it'
2 marks
(c) Sometimes a satellite suddenly stops being visible. However, you can usually see it again in another part of the sky later the same night. This can happen when there are no clouds in the sky and the satellite is overhead. Why does the satellite suddenly stop being visible?
The satellite goes into the Earth's shadow so no sunlight is shining on it.
Accept 'it is eclipsed' or 'it is not in thesunlight' or 'it is no longer reflecting the sunlight' accept 'it goes into the shadow of the Moon' or 'it goes in front of the Moon'
Do not accept 'it goes behind the Moon' or 'the Moon gets in the way'
1 mark
(d) Give one use of satellites in orbit around the Earth.
Any one from
- weather forecasting
- navigation or position finding
- communications accept 'satellite TV' or 'TV' or 'telephone' or 'radio'
- astronomy or looking at the stars
- to take pictures of the Earth accept 'spying' or 'surveillance' or 'to see changes in the environment or in land-use' accept 'for defence' or 'as weapons'
1 mark
Maximum 6 marks
About this site
