Police radar guns use radar (ie radio waves = light) they measure the difference in frequency between the outgoing signal and the doppler shifted return. It's very easy in electronics to accurately measure small frequency differences between two signals - much easier than measuring pulse time of flight for instance.Crazy Tosser said:Excuse me, I always thought police trap was sound waves, not light waves.
There is a trick to measure slight differences in two frequencies.Crazy Tosser said:Ok, so a 30 mph difference in speed produces a measurable difference in frequency of light?
Speed of light is 300,000km/s so 3000km/s is only a 1% shift. Stars are a continuum source so as 1% of the visible light is moved into the IR another 1% of the UV is moved into the visible. You do see the effect in very distant galaxies - they are red shifted out of the visible into the infrared.You would think that stars that travel at thousands km/sec away from us would not even be seen?
Crazy Tosser said:And how was the experiment performed, Vanadium?
The Doppler shift in light is a phenomenon where the wavelength of light appears to change due to the relative motion between the light source and the observer. This shift can either be towards the blue end of the spectrum (blue shift) or towards the red end (red shift).
The Doppler shift in light can be measured using a spectrometer, which separates light into its individual wavelengths. By analyzing the position of the spectral lines, scientists can determine if the light source is moving towards or away from the observer.
Yes, there is strong experimental evidence of the Doppler shift in light. This phenomenon has been observed in various astronomical objects, such as stars, galaxies, and even the cosmic microwave background radiation. It has also been demonstrated in laboratory experiments using moving light sources.
The Doppler shift in light plays a crucial role in our understanding of the universe. By studying the red and blue shifts of light from distant objects, scientists can determine the velocity and direction of their motion. This has helped us map the structure and expansion of the universe and discover the existence of dark matter and dark energy.
No, the Doppler shift in light cannot be used to directly measure the speed of light. This is because the Doppler shift is dependent on the relative motion between the light source and the observer, and the speed of light is constant regardless of the observer's motion. However, the Doppler shift can be used to indirectly measure the speed of objects in the universe, which can then be used to study the effects of gravity and the expansion of the universe.