Relativistic Doppler Effect

🔖 Topics

• Review of speed, wavelength, and frequency
• The relativistic Doppler effect
• Red shifting and blue shifting
• Examples of the relativistic Doppler effect in astronomy

🎯 Objectives

• Calculate the frequency shift of electromagnetic waves due to the relativistic Doppler effeect
• Describe how the emissions from an approaching or receding star change relative to an observer
• Describe how the Doppler effect shifts the emission spectra of elements in the periodic table

📋 Sequence

• Review of speed, wavelength, and frequency of EM waves
• Review of the non-relativistic Doppler effect for sound
• The Doppler effect for EM waves: \( f_o = f_s \sqrt{\frac{1 + \beta}{1 - \beta}} \)
• Redshifting and blueshifting

🖥️ Animations, Simulations, Activities

• Doppler Effect Animation - https://www.youtube.com/watch?v=ZRGg7e9b5wY
• Redshifting on the Universe - https://www.youtube.com/shorts/7R6rlYWwYec

📝 Practice Problems

1. Light of wavelength 659.6 nm is emitted by a distant star. The wavelength of the light as measured on Earth is 661.1 nm. How fast is the star moving with respect to Earth?

✅ Partial Solutions

1. 681000 m/s

📘 Connected Resources

• AlphaQrious. Redshifting on the Universe. #Redshift#Wavelength#Infrared. October 2021.
• Giambattista, Alan, et al. College Physics With an Integrated Approach to Forces and Kinematics. 5th ed., McGraw-Hill Education, 2020.
• meyavuz. Doppler Effect Animation. August 2011.