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Compare the formation and life cycles of stars with a similar mass to the Sun to stars with a much greater mass than the Sun - AQA - GCSE Physics - Question 6 - 2022 - Paper 1
Question 6
Compare the formation and life cycles of stars with a similar mass to the Sun to stars with a much greater mass than the Sun. Each arrow represents the velocity of ... show full transcript
Worked Solution & Example Answer:Compare the formation and life cycles of stars with a similar mass to the Sun to stars with a much greater mass than the Sun - AQA - GCSE Physics - Question 6 - 2022 - Paper 1
Step 1
Compare the formation and life cycles of stars with a similar mass to the Sun to stars with a much greater mass than the Sun.
Answer
Stars similar to the Sun form from a cloud of gas and dust (nebula) predominantly composed of hydrogen. Through gravitational forces, they condense to form a protostar, at which point nuclear fusion begins, converting hydrogen into helium. As they progress through their life cycle, they enter the main sequence stage where they remain stable due to the balance of gravitational and fusion forces.
In contrast, stars with a significantly greater mass undergo a similar initial condensation phase but evolve faster due to their greater gravitational pull and pressure. They rapidly move through their life cycles, burning through hydrogen quickly and expanding to become red supergiants. Eventually, their explosive end comes in the form of supernovae, leaving behind a neutron star or black hole depending on their initial mass.
Step 2
Describe what is meant by red-shift.
Answer
Red-shift refers to the observed increase in the wavelength of light emitted by galaxies as they move away from the observer. The phenomenon indicates that the light waves are being stretched, resulting in a shift towards the red end of the spectrum.
Step 3
Explain how Figure 11 provides evidence for the Big Bang theory.
Answer
Figure 11 shows that the furthest galaxies are moving away from the Milky Way at the highest velocities. This pattern suggests that all galaxies originated from a single point in the past, supporting the concept of an expanding universe, which is a key tenet of the Big Bang theory.
Step 4
Give the reason why scientists sometimes have to change theories about the universe.
Answer
Scientists are required to modify theories based on new observations or evidence that contradicts existing models, such as findings related to dark matter or dark energy, which challenge previous understandings of the universe.