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The Big Bang theory is one theory for the origin of the Universe - Edexcel - GCSE Physics - Question 4 - 2021 - Paper 1
Question 4
The Big Bang theory is one theory for the origin of the Universe. The Big Bang theory suggests: - the Universe had a beginning - the Universe is still expanding (a)... show full transcript
Worked Solution & Example Answer:The Big Bang theory is one theory for the origin of the Universe - Edexcel - GCSE Physics - Question 4 - 2021 - Paper 1
Step 1
Which of these provides evidence that the Universe had a beginning?
Answer
The correct option is D: the discovery of cosmic microwave background (CMB) radiation. This discovery provides strong evidence that the Universe had a beginning, as CMB radiation is considered a remnant of the hot, dense state of the early Universe.
Step 2
Describe how light from distant galaxies shows that the Universe is still expanding.
Answer
Light from distant galaxies exhibits a redshift phenomenon, where the wavelengths of light are stretched as the galaxy moves away from us. This redshift indicates that these galaxies are receding, supporting the theory that the Universe is continuously expanding. The greater the distance to the galaxy, the higher the redshift, which correlates with the expansion.
Step 3
Give one similarity and one difference when comparing the Big Bang theory with the Steady State theory.
Answer
Similarity: Both theories describe an expanding Universe.
Difference: The Big Bang theory posits that the Universe had a definite beginning, whereas the Steady State theory suggests that the Universe has no beginning and maintains a constant density through continual creation of matter.
Step 4
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Step 6
Explain why the gradient of the line in Figure 4 can only provide an estimate of the age of the Universe.
Answer
The gradient represents the rate at which galaxies are moving away from Earth. However, various factors such as dark energy, changes in the rate of expansion, and local gravitational effects can influence this rate, leading to only an estimate of the age of the Universe rather than an exact measure.