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Scientists no longer accept the geocentric model of the universe but it was the accepted theory for hundreds of years - Edexcel - GCSE Physics - Question 2 - 2016 - Paper 1
Question 2
Scientists no longer accept the geocentric model of the universe but it was the accepted theory for hundreds of years. Explain why the evidence available at the tim... show full transcript
Worked Solution & Example Answer:Scientists no longer accept the geocentric model of the universe but it was the accepted theory for hundreds of years - Edexcel - GCSE Physics - Question 2 - 2016 - Paper 1
Step 1
Explain why the evidence available at the time supported the geocentric model.
Answer
The geocentric model was supported by several pieces of evidence available at the time. Firstly, the apparent motion of the Sun and stars across the sky suggested that they were moving around the Earth, which seemed intuitive to observers.
Additionally, the lack of observable stellar parallax—the apparent shift of nearby stars against the background of more distant stars—reinforced the belief that the Earth was stationary. This distance was not measurable with the tools available in earlier centuries, leading people to conclude that Earth was at the center of the universe.
Step 2
Explain why red shift supports both theories but CMB supports only one of them.
Answer
Both the Big Bang theory and the Steady State theory predict an expanding universe. The red shift of light from distant galaxies indicates that these galaxies are moving away from us, which supports the fact that the universe is expanding.
However, the discovery of the Cosmic Microwave Background (CMB) radiation provides evidence for the Big Bang theory, as it suggests that the universe had a hot, dense beginning. Meanwhile, the CMB does not support the Steady State theory, which posits a constant density and does not imply a beginning.