Doppler Effect

Ambulance siren

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When an ambulance approaches the sound of its siren becomes higher pitched, i.e. its wavelength decreases, and when it moves away it becomes lower pitched, i.e. its wavelength increases. A similar effect occurs with light. When a star moves away the wavelength of its light increases. Check the difference in the sound of the siren when the ambulance is approaching and when it is moving away.

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Doppler effect and redshift

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When a star moves away, the wavelength of its light becomes longer, which causes its emission spectrum to approach red frequencies, producing an effect known as redshift. Check in our simulation what happens when the star is moved closer or farther away.

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