Will Red Shift Eventually Make Distant Light Unobservable?

In summary, the edge of the observable universe is determined by the time it takes for light to reach us, not by the redshift of the light. However, over time, the redshift will continue to increase and the objects at the edge of the observable universe will become more redshifted, making them harder to detect. The Cosmic Microwave Background (CMB) will eventually move too far into the red part of the spectrum to be detectable, but it will never leave the electromagnetic spectrum.
  • #1
stargazer843
10
0
Since light emitted farther away from our point in the universe is more and more red shifted, would this mean that at a certain time we wouldn't be able to observe light further than a fixed distance since it's been red shifted beyond the electromagnetic spectrum?
 
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  • #2
Yes. That's the edge of the observable universe. Every year, it gets several light-years farther out from us (not just 1 light-year, since space is expanding while the light is in transit).
 
  • #3
Redshifted galaxies will become increasingly redshifted over time. They will never suddenly 'blink' out of view. Redshift is a continuous, not discrete, function.
 
  • #4
@Chronos Eventually it will be redshifted out of the electromagnetic spectrum though right?
 
  • #5
bcrowell said:
Yes. That's the edge of the observable universe. Every year, it gets several light-years farther out from us (not just 1 light-year, since space is expanding while the light is in transit).

Ben, I guess I have another misunderstanding that I need you to clear up. I thought the edge of the observable universe was the place at which objects exist from which emitted light has had time to reach us based on their position and their speed of recession from us and that we couldn't see beyond that point because the photons from those objects is now traveling away from us due to recession faster than they are traveling towards us due to their local speed. Clearly my concept IS tied up with red-shift so I'm having difficulty formulating my question well (another sign that I'm obviously confused). I guess at heart my belief is that the edge of the OU is based on time, not redshift and my question is an amorphous "HELP --- please get me unconfused"

Thanks.
 
  • #6
The CMB will eventually move so far into the 'red' it will be cease to be detectable, but, never leave the EM spectrum.
 

FAQ: Will Red Shift Eventually Make Distant Light Unobservable?

What is red shift?

Red shift is a phenomenon in which the wavelength of light from an object appears to be stretched towards the red end of the spectrum. This is due to the object's relative motion away from the observer, causing a shift in the light's frequency.

How is red shift related to the expansion of the universe?

The red shift observed in the light from distant galaxies is evidence of the expansion of the universe. As the universe expands, the space between objects also expands, causing the light from those objects to appear to shift towards the red end of the spectrum.

What causes red shift?

Red shift is caused by the Doppler effect, which is the change in frequency of waves (including light waves) due to the relative motion between the source and the observer. In the case of red shift, the source of light is moving away from the observer, causing the wavelength to appear stretched and the frequency to appear lower.

How is red shift used to measure the distance of objects in space?

The amount of red shift observed in the light from an object can be used to determine its distance from Earth. This is because the amount of red shift is directly proportional to the object's recessional velocity, which can then be used to calculate its distance using the Hubble's law.

What is the difference between red shift and blueshift?

Red shift refers to the shift towards the red end of the spectrum, while blueshift refers to the shift towards the blue end of the spectrum. Red shift is observed when an object is moving away from the observer, while blueshift is observed when an object is moving towards the observer. Both are caused by the Doppler effect, but in opposite directions.

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