The visible part of the electromagnetic spectrum from a star includes a dark line. This line is at a specific wavelength. The diagram shows the position of the dark line in the spectrum from the Sun and in the spectrum from a distant galaxy.

(a) Explain how the spectrum ‘shift’ of the dark line supports the theory that the Universe began from a very small point.

(3 marks)

(b) From data collected, a graph can be drawn that links the speed of a galaxy with the distance of the galaxy from the Earth.

(i) How does the visible light spectrum from galaxy A look different from the visible light spectrum from galaxy B?

What is the maximum time that she could sunbathe without burning if she used
‘factor 30’ sunscreen on her skin?

(1 mark)

(ii) A third galaxy, C, seems to be travelling away from the Earth at about 60 000 km/s.

Estimate how far galaxy C might be from the Earth, showing how you use the graph to do this.

Distance between galaxy C and the Earth = .............................. million light years

(1 mark)

(c) Astronomers use telescopes to observe distant galaxies. Since 1990 the Hubble optical telescope has been in orbit around the Earth.

Explain why an optical telescope in space allows astronomers to see further and more clearly than an optical telescope on Earth.

(2 marks)

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From Q3 P1 AQA January 2007