The Doppler effect is the change in a wavelength when the source of the wave is moving. You may notice this every day, if you are on the street and a car passes you. When the car is coming toward you, the sound waves are 'pushed faster toward you', causing the engine sound to be higher. Then, when the car passes, the sound waves are 'pulled slower away from you', and the car sounds become lower.
With visible light, faster wavelengths are more 'blue', where slower wavelengths are more 'red'. When examining the light of stars, astronomers look at particular patterns in the light that are caused by specific chemical reactions in the star. But sometimes those patterns suggest the star looks 'more red' than it should be. The Doppler effect suggests that this is because the star is moving away from us, so the wavelengths are slower than 'normal'. Similarly, if the light patterns are more 'blue', than the star may be moving toward us.
Hope this helps!
With visible light, faster wavelengths are more 'blue', where slower wavelengths are more 'red'. When examining the light of stars, astronomers look at particular patterns in the light that are caused by specific chemical reactions in the star. But sometimes those patterns suggest the star looks 'more red' than it should be. The Doppler effect suggests that this is because the star is moving away from us, so the wavelengths are slower than 'normal'. Similarly, if the light patterns are more 'blue', than the star may be moving toward us.
Hope this helps!
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When the Doppler effect is applied to light it is known as "blue shift" or "red shift" depending on whether the light source is moving toward you or away from you.
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