Question

How is the Doppler effect related to understanding the universe?

Answer 1

Hint: In order to answer the above given problem we must understand Doppler effect .
Doppler effect is the change in wave frequency during relative motion between a wave source and its observer.
Using the detailed discussion about the Doppler effect we will relate the Doppler effect with the universe.

Complete answer:
Let's discuss the Doppler effect in order to get the relation in understanding the universe.
The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency , the received frequency is higher during the approach, identical at the instant of passing by and lower during the recession.
The Doppler effect shows us that the universe is expanding by showing us a red shift. It shows us which way objects in the universe are revolving.

In universe when the apparent change in wavelength can be observed for the visible light emitted by stars or galaxies. So, if a star is moving towards earth , it appears to emit light that is shorter in wavelength compared to a source of light that isn't moving. Shorter wavelength corresponds to a shift towards the end of the spectrum , this is called blue shift. In the similar manner if the light from the star tends to move away from us it seems to shift towards a longer wavelength which is towards the red end of the spectrum it is called red shift. Degree of red or blue shift gives Astronomers the information about how fast the object (in the universe) is moving relative to us.

Note: Generally Doppler effect is used in some types of radar to measure the velocity of detected objects. A radar beam is fired at a moving target for example a motor car, as police use radar to detect speeding motorists as it approaches or recedes from radar source. Used in SONAR systems, hydro acoustic current meters are used to measure the water current velocity.