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Evidence to support the Big Bang theory comes from cosmological microwave background radiation and the relative abundance of hydrogen and helium in the Universe - AQA - A-Level Physics - Question 4 - 2018 - Paper 4
Question 4
Evidence to support the Big Bang theory comes from cosmological microwave background radiation and the relative abundance of hydrogen and helium in the Universe. 04... show full transcript
Worked Solution & Example Answer:Evidence to support the Big Bang theory comes from cosmological microwave background radiation and the relative abundance of hydrogen and helium in the Universe - AQA - A-Level Physics - Question 4 - 2018 - Paper 4
Step 1
Explain what is meant by cosmological microwave background radiation and how its existence supports the Big Bang theory.
Answer
Cosmological microwave background radiation (CMBR) refers to the afterglow of the Big Bang, essentially radiation that fills the universe. It is a form of electromagnetic radiation that originated when the universe was approximately 380,000 years old and has since cooled to a temperature of about 2.7 K.
CMBR supports the Big Bang theory as it provides critical evidence that the universe was once in a hot and dense state. This radiation is uniformly detected from all directions in space, consistent with the idea that it has been redshifted as the universe expanded. The spectrum of CMBR has a peak in the microwave region, which aligns with predictions made by the Big Bang theory.
Step 2
Explain how the relative abundance of hydrogen and helium supports the Big Bang theory.
Answer
The relative abundance of hydrogen and helium serves as additional evidence for the Big Bang theory. According to this theory, the universe started off hot and dense, allowing for nuclear fusion processes that created elements.
Observations reveal a significant abundance of hydrogen (about 75%) and helium (about 25%) in the universe today. This is consistent with predictions based on Big Bang nucleosynthesis, the process that occurred in the early minutes after the Big Bang. The ratio of helium to hydrogen supports the theory as it aligns closely with calculations made for those conditions, providing strong evidence for the Big Bang's validity.