Theoretical Extent of Redshift - How Far Can It Go?

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In summary, the Redshift phenomenon can theoretically shift frequency to extremely low levels as a result of the doppler-like effect. However, there is no known lower limit for this shift. According to the equation for the relativistic doppler effect, even if an object is moving at a speed of 299,792,457 m/s (slightly less than the speed of light), the resulting frequency shift would still be significant.
  • #1
Wes Tausend
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How far can the Redshift phenomenon theoretically shift frequency? I believe I understand the doppler-like effect, but have never seen this question regarding extreme RF shift asked before.

One might think that if a relative object moved away very near the speed of light that the radio emission frequency might drop so low as to be very near subsonic levels. Or perhaps zero frequency at full lightspeed, if the weakened signals were somehow still detectable.

Thanks,
Wes
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I can't see any reason why there should be a lower limit.
 
  • #3
Well, if you look up the equation for the relativistic doppler effect, you will get something like this. If you plug in 299,792,457 m/s for v (1 m/s less than c), and let v_source be 1, you get a factor 24486.427. Hopefully this is what you meant?
 

1. What is redshift and how does it relate to distance?

Redshift is a phenomenon in which light from distant objects appear to have longer wavelengths, indicating that the object is moving away from us. This is known as the Doppler effect and is caused by the expansion of the universe. The amount of redshift can be used to calculate the distance of the object, with higher redshifts indicating greater distances.

2. How is the theoretical extent of redshift determined?

The theoretical extent of redshift is determined by the speed at which the universe is expanding. This is known as the Hubble constant and is currently estimated to be around 70 km/s per megaparsec. This means that for every megaparsec (3.26 million light years) of distance, an object will appear to be moving away from us at 70 km/s faster than the previous megaparsec.

3. Is there a limit to how far redshift can go?

According to current theories, there is no limit to how far redshift can go. As the universe continues to expand, the redshift of distant objects will continue to increase. However, the rate of expansion may change over time due to various factors, so the theoretical extent of redshift could change in the future.

4. Can redshift be used to determine the age of the universe?

Yes, the amount of redshift can be used to calculate the age of the universe. This is done by comparing the observed redshift of an object to the predicted redshift based on the Hubble constant. The greater the redshift, the further back in time the light was emitted, providing information about the age of the universe.

5. Are there any other factors that can affect redshift and its theoretical extent?

Yes, there are other factors that can affect redshift, such as the gravitational pull of objects between the observer and the distant object. This is known as gravitational redshift and can slightly alter the observed redshift. Other factors such as the expansion rate of the universe and the density of matter can also impact the theoretical extent of redshift.

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