Doppler Effect in Accelerating Frames vs Normal Doppler Effect

In summary: These effects are due to the fact that mass affects the way gravity twists space and time. ie. objects closer to the observer have a shorter distance between them and the observer, so the light from the closer object will take longer to reach the observer and will be shifted towards the blue end of the spectrum.This can be both the "classical" version or the relativistic version of the Doppler effect, depending on how close this velocity is to c.The effect of velocity on the frequency of light is due to a phenomenon called the gravitational equivalence principle. This states that the mass of an object affects the way space and time curve around it, and this in turn affects the way light is seen.
  • #1
Hydr0matic
197
1
What is the difference in magnitude between the effects of normal doppler effect and doppler effect in accelerated frames, e.g. when the (light)source is accelerating wrt the observer? What is the formula for doppler effect in accelerating frames?
 
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  • #2
Hydr0matic said:
What is the difference in magnitude between the effects of normal doppler effect and doppler effect in accelerated frames, e.g. when the (light)source is accelerating wrt the observer? What is the formula for doppler effect in accelerating frames?

What do you mean by normal Doppler effect ?

When velocity of source/observer is not constant, the shift in frequence will be time dependent. It is expressed by the v-formula that depends on time, initial velocity and acceleration.



marlon
 
  • #3
By normal I mean with constant relative speed.
Since we are dealing with light and spacetime I just assumed that, like in relativity, accelerated frames behave differently.
http://www.du.edu/~jcalvert/phys/doppler.htm
Relativity must be taken into account for the optical Doppler effect, since light, with its velocity of c, is an essentially relativistic object.
Surely, doppler shift from a lightsource with relativistic and extremely accelerating speed isn't governed by the classical doppler formula?
 
  • #4
Hydr0matic said:
By normal I mean with constant relative speed.

This can be both the "classical" version or the relativistic version of the Doppler effect, depending on how close this velocity is to c.

Surely, doppler shift from a lightsource with relativistic and extremely accelerating speed isn't governed by the classical doppler formula?

Well, in the case of high velocities, the principles of special relativity need to be applied.

marlon
 
  • #5
To see what effect acceleration has on the frequency/wavelength of light you can invoke Einstein's (gravitational) equivalence principle. Light from a massive object would be seen as red shifted by a distant observer and to an observer closer to the massive object light from a more distance source would be seen as blue shifted.
 

1. What is the Doppler Effect in accelerating frames compared to the normal Doppler Effect?

The Doppler Effect in accelerating frames refers to the change in frequency and wavelength of a wave when the source or observer is accelerating. This is different from the normal Doppler Effect, which only takes into account the relative motion between the source and observer.

2. How is the Doppler Effect in accelerating frames calculated?

The Doppler Effect in accelerating frames is calculated using the general formula for the Doppler Effect, which takes into account the acceleration of the source or observer. This formula is:
Δf/f = [(v/c) + (a/c)t]-1
Where Δf is the change in frequency, f is the original frequency, v is the relative velocity between the source and observer, c is the speed of the wave, a is the acceleration of the source or observer, and t is the time interval.

3. What are some real-life examples of the Doppler Effect in accelerating frames?

One example is the change in frequency of a siren on an accelerating ambulance. As the ambulance moves towards or away from an observer, the frequency of the siren will change due to the acceleration of the ambulance. Another example is the redshift and blueshift observed in the light from distant galaxies, which can be explained by the Doppler Effect in accelerating frames caused by the expansion of the universe.

4. How does the Doppler Effect in accelerating frames affect sound and light waves differently?

The Doppler Effect in accelerating frames affects sound and light waves differently because they have different speeds. Sound waves travel at a much slower speed than light waves, so the acceleration of the source or observer has a greater impact on the frequency and wavelength of sound waves compared to light waves. Additionally, the Doppler Effect for light waves is also affected by the relative motion of the source and observer due to the constant speed of light.

5. Can the Doppler Effect in accelerating frames be observed in everyday life?

Yes, the Doppler Effect in accelerating frames can be observed in everyday life. As mentioned before, the change in frequency of a siren on an accelerating ambulance is one example. Other examples include the change in frequency of a car horn as it accelerates towards or away from an observer, or the change in frequency of a train whistle as it rounds a corner. Additionally, the Doppler Effect in accelerating frames is also used in various technologies, such as radar and sonar systems.

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