Exploring Blue & Red Shifts: Effects & Explanations

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In summary, blue shift and red shift are terms used by astronomers to describe frequency shifts in light. Blue shift refers to light with a higher frequency, while red shift refers to light with a lower frequency. These shifts can be caused by motion towards or away from an observer, or by the expansion of space. By measuring the redshift, astronomers can determine the speed at which an object is moving or the amount of expansion of space. The conventional symbol for redshift is z, and a ten percent decrease in frequency corresponds to z = 0.1, which can be interpreted as either motion away from an observer or an expansion of space during the light's passage.
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Can anyone explain what is blue shift and red shift?? And what effects they have?
 
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Originally posted by Koveras00
Can anyone explain what is blue shift and red shift?? And what effects they have?

blue shift and red shift are the astronomers' words for
frequency shifts up or down
blue shifted light is light with the frequency shifted up
(by motion towards, doppler-fashion)

redshifted light is light with the frequency shifted down
(either by motion away, doppler, or by the expansion of
the space in between, or by a gravity effect)

the light from each kind of atom has a distinctive recognizable pattern of spectral lines, so if you see some hot hydrogen gas you can recognize that it is hydrogen and you can tell (from measurements in the laboratory with the same gas) what
frequencies it OUGHT to be emitting.

So if you measure the light that is actually getting to you and find that it is redshifted by ten percent (frequency ten percent lower, or wavelength ten percent longer) then you say "z = 0.1"

z is the conventional symbol for the redshift, the fractional (increase in wavelength, or) decrease in frequency. So a ten percent decrease in frequency means "z = 0.1".

And that corresponds to the doppler effect of motion away by approximately one tenth of the speed of light.

Or a ten percent stretchout of space during the time the light was on its way to you.

There are some fine points and an improved doppler formula and some ambiguities about what is relative motion away and what is the expansion effect, but basically the redshift z = 0.1 would be interpreted as nearly all due to a tenpercent expansion of space during the light's passage and it would be informally talked about as if it were due to the emitter moving away at one tenth the speed of light.
 
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1. What is a blue shift and red shift?

A blue shift occurs when the light emitted from an object appears to have shorter wavelengths, shifting towards the blue end of the light spectrum. A red shift occurs when the light appears to have longer wavelengths, shifting towards the red end of the light spectrum.

2. What causes blue and red shifts?

Blue and red shifts are caused by the Doppler Effect, which is the change in frequency and wavelength of a wave as the source of the wave and the observer of the wave move towards or away from each other. In the case of blue and red shifts, this is due to the movement of celestial objects in space.

3. How do blue and red shifts affect our understanding of the universe?

Blue and red shifts provide scientists with valuable information about the movement and distance of objects in the universe. By studying the amount of shift in the light emitted from a celestial object, scientists can determine its velocity, distance, and direction of movement.

4. Can blue and red shifts be observed in objects other than stars?

Yes, blue and red shifts can be observed in a variety of celestial objects such as galaxies, quasars, and even the cosmic microwave background radiation. They can also be observed in non-celestial objects, such as sound waves and water waves.

5. Are blue and red shifts only caused by the Doppler Effect?

No, there are other factors that can cause blue and red shifts, such as gravitational redshift, which occurs when light is affected by the gravitational pull of massive objects. Additionally, the expansion of the universe also causes a redshift in the light from distant objects.

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