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Cosmology (A-level only)

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Question 2

As of 2024, astronomers have confirmed the existence of over 5,500 exoplanets. A primary objective of modern astrophysics is to detect and characterize Earth-twin planets—planets of similar size and mass to Earth orbiting within the habitable zone (around 1 AU1\text{ AU}1 AU) of Sun-like (G-type) stars.

Discuss the physical principles and the specific observational challenges associated with using the following three methods to detect such a planet:

  • The transit method
  • The radial velocity (Doppler) method
  • Direct imaging (observation)

In your answer, compare these methods and suggest which has been, or is likely to be, the most successful for detecting this specific class of planet, justifying your choice.

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Markscheme

Cosmology (A-level only) Questions

  1. A Level
  2. /Physics
  3. /Cosmology (A-level only)

15 exam-style questions on AQA A Level Physics Cosmology (A-level only), covering Doppler effect (A-level only), Hubble's law (A-level only), Quasars (A-level only), and Detection of exoplanets (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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