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An introduction to exoplanets
An introduction to exoplanets

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7  Summary of Week 3

This week you’ve learned about the first exoplanet discovered orbiting a Sun-like star. This planet is 51 Pegasi b, a ‘hot Jupiter’. You have seen how planets can be detected by measuring the movements of wobbling stars – the radial velocity method. This has introduced you to spectroscopy: the science of spreading out the light from an object to separate the colours from one another. There is a lot of information that can be extracted using spectroscopy – what you have learned here is only the beginning. You have also had the chance to explore the website and make your own spectrometer. Finally, in the interactive application activities you have explored the consequences of one of the most important laws in astronomy: Kepler’s Third Law.

You should now be able to:

  • interpret the name of an exoplanet
  • describe the characteristics of 51 Pegasi b
  • explain the radial velocity method for detecting planets using the analogy of a see-saw
  • understand that both light and sound are waves
  • understand how the Doppler shift affects wave properties
  • use the website [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] to find a list of planets discovered by the radial velocity method.

Next week you will be looking at another very successful way of detecting exoplanets – the transit method.

You can now go to Week 4.