Why do scientists observe blueshift in certain stars?
a. Light wave frequencies decrease as an object moves toward the observer
b. Stars with lower temperatures emit more light waves at the blue end of the spectrum
c. Light wave frequencies increase as an object moves toward the observer
d. Stars with higher temperatures emit more light waves at the blue end of the spectrum
c. Light wave frequencies increase as an object moves toward the observer
The correct answer is c. Light wave frequencies increase as an object moves toward the observer.
When a star is observed to have a blueshift, it implies that the wavelengths of the light coming from the star are compressed or shifted towards the blue end of the spectrum. This phenomenon occurs because the star is moving towards the observer. Just like the sound of a moving object will have a higher pitch when moving towards an observer, the frequency of light waves will increase as the source moves closer.
The correct answer is c. Light wave frequencies increase as an object moves toward the observer.
Scientists observe blueshift in certain stars because of the Doppler effect. The Doppler effect is the perceived change in frequency of a wave when the source of the wave or the observer is in motion relative to one another. In the case of light waves, this effect causes a shift in the color of light.
When an object, such as a star, moves toward the observer, the light waves emitted by the star get compressed due to their motion. This compression leads to an increase in the frequency of the light waves. Since different frequencies of light correspond to different colors, an increase in frequency shifts the color of the light towards the higher frequencies, which include the blue end of the spectrum. This shift towards the blue end is known as blueshift.
Therefore, when scientists observe blueshift in certain stars, it indicates that those stars are moving towards the observer. By studying the magnitude of the blueshift, scientists can infer the speed and direction of a star's motion.