The question is "What best describes Gravitational redshift?"
A) An affect on time
B) An affect on gravity
C) An affect on color
I answered C but got it wrong on the quiz. In the book it says
"Light traveling 'against gravity' is observed to have a slightly lower frequency due to an effect called the gravitational red shift. Because red light is at the low-frequency end of the visible spectrum, a lowering of frequency shifts the color of the emitted light toward red."
How is C not the right answer? I spoke to the teacher after class and he referenced to a different part in the book where it said,
"Gravity causes clocks to run slow. A clock at the surface of Earth runs slower than a clock farther away."
But where he quoted the book from never even mentions the word gravitational redshift. And even if "A" is the right answer he shouldn't throw out red herrings like that where the book makes it seem like "C" is the right answer.
A) An affect on time
B) An affect on gravity
C) An affect on color
I answered C but got it wrong on the quiz. In the book it says
"Light traveling 'against gravity' is observed to have a slightly lower frequency due to an effect called the gravitational red shift. Because red light is at the low-frequency end of the visible spectrum, a lowering of frequency shifts the color of the emitted light toward red."
How is C not the right answer? I spoke to the teacher after class and he referenced to a different part in the book where it said,
"Gravity causes clocks to run slow. A clock at the surface of Earth runs slower than a clock farther away."
But where he quoted the book from never even mentions the word gravitational redshift. And even if "A" is the right answer he shouldn't throw out red herrings like that where the book makes it seem like "C" is the right answer.
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The speed of light is the same no matter what. So when that photon is near a massive gravity source, its speed is marked by ds/dt = c. But out in normal space, where the observer stands, the speed is dS/dT = c.
Because of the GTOR effect on time the rate of time is dt < dT where dT is normal time away from the gravity source. So c dt = l < L = c dT and the photon's wavelength close in to the gravity source is l = c dt = c/F and as it gets to you it shifts to L = c dT = c/f.
And there you are. That photon's color shifts from a higher energy E = hF in close to the gravity source to a lower one e = hf as it approaches Earth. That is, its color shifts to the red end of the spectrum as it pulls away from the big gravity.
And there you are. The correct answer is A and C. Time for each photon goes from dt to dT as it approaches Earth, and energy goes from E = hF to e = hf so its color shifts to the lower energy, red end. In other words, it's the affect on time (A) that effects the color shift (C) to red.
Take this to your instructor. I think he/she should throw this question out.
Because of the GTOR effect on time the rate of time is dt < dT where dT is normal time away from the gravity source. So c dt = l < L = c dT and the photon's wavelength close in to the gravity source is l = c dt = c/F and as it gets to you it shifts to L = c dT = c/f.
And there you are. That photon's color shifts from a higher energy E = hF in close to the gravity source to a lower one e = hf as it approaches Earth. That is, its color shifts to the red end of the spectrum as it pulls away from the big gravity.
And there you are. The correct answer is A and C. Time for each photon goes from dt to dT as it approaches Earth, and energy goes from E = hF to e = hf so its color shifts to the lower energy, red end. In other words, it's the affect on time (A) that effects the color shift (C) to red.
Take this to your instructor. I think he/she should throw this question out.
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It's a spectral shift, yes. But it doesn't AFFECT colour. Red is still red, blue is still blue, etc.
A shift towards red is CAUSED by gravitational time dilation.
So if you are asked what BEST describes GRAVITATIONAL redshift, it has to be A.
I'll back the teacher.
A shift towards red is CAUSED by gravitational time dilation.
So if you are asked what BEST describes GRAVITATIONAL redshift, it has to be A.
I'll back the teacher.
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Fuzzy wording of question. It's an effect *of* time dilation, but the effect is *on* perceived color.
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Yes, he's wrong.
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c seems like the right answer to me!