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GCSE level questions on the Earth in Space

Q12.

(a) Brown dwarf stars are thought to have been formed in the same way as other stars.

They are too small for nuclear fusion reactions to take place in them.

Brown dwarf stars emit infrared radiation but are not hot enough to emit visible light.

(i) Describe how a star is formed.

Dust and gas/hydrogen (a nebula) in outer space is pulled together by gravitational attraction or gravitational forces or gravity

[2 marks]

(ii) Describe the process of nuclear fusion.

Fusion is the joining of two (atomic) nuclei (to form a larger one)

If you just say atoms join instead of nuclei you get no marks!

[1 mark]

(iii) Scientists predicted that brown dwarf stars existed before the first one was discovered in 1995.

Suggest one reason why scientists are now able to observe and identify brown dwarf stars.

We now have developed more sensitive astronomical instruments/telescopes such as infrared telescopes.

Just saying we have more knowledge now was insufficient to get you a mark. It is our improved technology that enables us to see them.

[1 mark]

(b) In the 18th century some scientists suggested a theory about how the planets formed in the Solar System. The theory was that after the Sun formed, there were cool discs of matter rotating around the Sun. These cool discs of matter formed the planets. The scientists thought this must have happened around other stars too.

(i) Thinking about this theory, what would the scientists have predicted to have been formed in other parts of the Universe?

They led to the prediction of other planets, orbiting other stars.

[1 mark]

(ii) Since the 1980s scientists studying young stars have shown the stars to be surrounded by cool discs of rotating matter.

What was the importance of these observations to the theory the scientists suggested in the 18th century?

They provided evidence/proof to support theory

[1 mark]

(c) The Earth contains elements heavier than iron.

Why is the presence of elements heavier than iron in the Earth evidence that the Solar System was formed from material produced after a massive star exploded?

Elements heavier than iron are only formed only when a massive star explodes as a supernova - stars can only fuse elements up to (and including) iron - it takes a supernova to produce more massive neuclei.

[1 mark]

(Total 7 marks)