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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, proposed by Ptolemy, was supported by several pieces of evidence that seemed logical given the observational technology of the time. Firstly, the apparent motion of the stars and planets across the night sky suggested that they revolved around a stationary Earth. Secondly, the lack of observable stellar parallax—where nearby stars would shift positions relative to distant stars as Earth moved—seemed to confirm that Earth was stationary. Furthermore, the phases of Venus observed by astronomers such as Galileo, though later deemed a misinterpretation, initially seemed to fit the geocentric model's predictions. Thus, the logical interpretations of observable phenomena supported the acceptance of the geocentric view for centuries.
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, which is supported by the observation of red shift in light from distant galaxies. This red shift indicates that galaxies are moving away from us, suggesting that the universe is expanding under both models. However, the discovery of the Cosmic Microwave Background (CMB) radiation provides evidence exclusively supporting the Big Bang theory. The CMB is interpreted as the remnant heat from the early universe, confirming the idea that the universe had a beginning, which aligns with the Big Bang. In contrast, the Steady State theory posits a universe that has always existed without a singular beginning, hence the CMB contradicts this theory.