Blueshift

Definition

Blueshift is the phenomenon where light or other electromagnetic radiation from an object moves towards shorter wavelengths. This typically indicates that the object emitting the light is moving closer to the observer.

5 Must Know Facts For Your Next Test

1. Blueshift occurs when an astronomical object moves towards us, causing its light wavelengths to compress.
2. It is a direct consequence of the Doppler Effect, specifically for objects approaching the observer.
3. The amount of blueshift can be used to determine the speed at which an object is approaching.
4. In spectra, blueshifted lines appear shifted towards the blue end of the spectrum compared to their rest positions.
5. Blueshift is less commonly observed in astronomy than redshift because most objects in the universe are moving away from us due to cosmic expansion.

Review Questions

• What does blueshift indicate about an object's movement relative to an observer?
• How does blueshift relate to the Doppler Effect?
• Why are blueshifts less commonly observed in astronomy compared to redshifts?

Related terms

redshift:

Redshift is the phenomenon where light or other electromagnetic radiation from an object moves towards longer wavelengths, indicating that it is moving away from the observer.

Doppler Effect:

The change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.

spectral line:

A dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light at a specific wavelength by a substance.