Expanding Universe and the Red Shift

ynot said:
No - I am suggesting that different parts of the light spectrum might travel at different speeds. Red faster than blue.
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If the speeds are constant, and the sources are equidistant to the observer, than the difference will be the same no matter how distant the light is.
 
Melendwyr - You're an idiot if you choose to argue with SpaceFluffer about astrophysics.

You think that some others are agreeing with you, but you're not listening to what they're actually saying. You're out on a limb.

As to your 'no one really knows' statement - it was totally irresponsible. You implied to ynot and others that don't know any better that you are sufficiently well informed to make this strong statement, which will be interpreted by most as 'no one has a clue'. Several people do have a clue and they are actively investingating their various hypotheses.

You play games by saying that that isn't the same as 'knowing'. Well, sir, start listing the things that you 'know', for you seem to regard 'knowing' as being different in kind rather than different in degree from hypothesizing.

I don't 'know' anything in this sense, and I'm damned sure that you don't either.

Learn more, listen better, and quit sounding authoritative when you're not.
 
Guess I’m having a hard time understanding what you’re trying to say, not that my understanding of the subject is needed of course.

Melendwyr said:
How would you get two things moving away from each other, from their own perspectives, faster than the speed of light?
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If you took two laser pointers and set them on a table facing away from each other, then wouldn’t any given photon going left be moving away from you at twice the speed of light from the perspective of sitting on a photon going right?

For a different example, without using light itself, lets say we can build rockets that could only go 3/4 the speed of light indefinitely. Launch them so they are moving exactly 180 degrees from each other. They wouldn’t be breaking the cosmic speed limit, but relative to each other they appear to be moving faster then light (even more so if space continued to grow between them also). Could you have a radio conversation between them?

Melendwyr said:
With expanding space, the longer photons travel, the more space there is between their vibrational nodes. Therefore they have less energy than they did when they were originally released.

If you invoke Tired Light to explain the observations, you don't get anywhere. If you invoke the expansion of space, one of the consequences of that is that photons will gradually lose their energy as they travel.
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Anything that loses energy over time will eventually run out of energy if given enough time wouldn’t it? That means that over a long enough time the light energy will just fizzle out, and I believe that breaks the 1st law of thermodynamics.

Each time I try to visualize what your saying about space expanding between light’s “vibrational nodes” (not sure if I’m using this term correctly, I’m thinking of the distance between wave peaks) that eventually leads me to think the wave will flat line. If you keep expanding the space between the peaks the wave will become flat.

What is a flat electromagnetic wave? Is that when the energy fizzles out?
 
c4ts said:
If the speeds are constant, and the sources are equidistant to the observer, than the difference will be the same no matter how distant the light is.
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Scratch that, because I thought you were saying there was some kind of delay based upon wavelengths, but you were talking about the actual speed of the photon.

You can "race" photons at different wavelengths and see if they synch up, though.
 
Complexity said:
You think that some others are agreeing with you, but you're not listening to what they're actually saying. You're out on a limb.
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No, they're disagreeing with me, even though what they're actually saying is what *I've* been saying. It's immensely frustrating.

As to your 'no one really knows' statement - it was totally irresponsible.
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It's one of the great unanswered questions that science is currently struggling with, and you think that acknowledging it as a mystery is irresponsible?

I'm really not interested in conversing with you any longer.
 
I less than three logic said:
If you took two laser pointers and set them on a table facing away from each other, then wouldn’t any given photon going left be moving away from you at twice the speed of light from the perspective of sitting on a photon going right?
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No. That's one of the weird consequences of Relativity. No matter how you're moving, or how it's moving relative to you, the speed of light in a vacuum is always a constant: c.
 
c4ts said:
Scratch that, because I thought you were saying there was some kind of delay based upon wavelengths, but you were talking about the actual speed of the photon.
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Yes!

You can "race" photons at different wavelengths and see if they synch up, though.
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You must mean the "royal" you as I personally don't have the equipment or knowledge to do this.
 
But you do understand that even if different wavelengths of light travelled at different velocities, this could not be used to explain red shift?
 
ynot said:
Yes!


You must mean the "royal" you as I personally don't have the equipment or knowledge to do this.
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This would explain why you have the theory in the first place...

I suggest you explain the theory to Stephen Hawking and beg him to help you set up an experiment. He's the only astrophysicist I can think of who won't laugh in your face.
 
c4ts said:
This would explain why you have the theory in the first place...

I suggest you explain the theory to Stephen Hawking and beg him to help you set up an experiment. He's the only astrophysicist I can think of who won't laugh in your face.
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What a good idea! - Do you have his number?

Would rather have people laugh in my face than behind my back.

So I guess it is your best method for anyone trying to learn and understand is to not have independent thoughts or ask questions.

From my initial post - I’m not an academic so hope my half-baked ideas aren’t too simplistically naïve. If you’re not rolling around the floor with laughter, I would appreciate any feedback anyone cares to offer.
 
Hello ynot,

It's ok to challenge the currently accepted theories. After all, these theories themselves came about as challenges to the existing theories of the time. At the time they came about, though, they were seriously challenged by the scientific community. Other scientists developed competing theories, but they were eventually discarded. The theories we have now will stand until observations are made that reveal a shortcoming in the theories. But as long as these theories provide good explanations and predictions for observed phenomena, competing theories are going to have a very difficult time gaining acceptance.

Also, you seem to have some confusion as to what science is and why scientists believe the things they do. My advice to you is to go to a large bookstore and get yourself a *big* book on astronomy. Astronomy is more than a collection of what scientists believe, it is the story of how we have come to believe what we believe. Every important theory since the time of Copernicus and Galileo has met with serious challenges. Theories that replaced old ideas eventually got challenged by new theories and have now been forgotten. For example, there was once a great controversy as to whether 'planetary nebulae' were spiral-shaped clouds or actual star formations located far from our own galaxy. Now we all accept that other galaxies are very, very far away but there was a time when this was a radical idea. I know you think it is dogmatic when someone gives you a short answer to your questions, but read about astronomy and you'll see that all of these theories were heavily criticized before they eventually gained acceptance.
 
ynot said:
You must mean the "royal" you as I personally don't have the equipment or knowledge to do this.
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It wouldn't be that difficult to get. You could perform such an experiment, for example, by looking at the occultations of stars.

If, for example, red light did actually travel faster than blue light, you could observe the planet Jupiter as it passed in front of a star. As the star disappeared behind Jupiter, you would see the red light disappear first (which would mean the star momentarily appeared to be more bluish than normal), and as the star reappeared, you would see the red light appear first (making the star more reddish than normal). A simple telescope and a high-speed camera would let you test this hypothesis --and any reasonably-sized university physics department has such toys available if you talk to the relevant professors.

Having said this -- such experiments have already been done; spectral analysis of stars is something of a cottage industry. And it's precisely from such spectral analysis that we have learned that the spectral lines themselves shift within the starlight.
 
So let me see if I understand this difference of opinion between SpaceFluffer and Melendwyr. Melendwyr seems to be saying that the expansion of space causing the redshift is equivalent to the Tired Light Hypothesis, if I can capitalize that. SpaceFluffer strenuously disagrees, because the TLH is an attempt to explain how, given a static universe, that we observe the redshift. Given those constraints, it can be shown that the TLH violates our understanding of QM.

However, Melendwyr agrees that the universe is expanding. It doesn't help that she is arrogant in how she phrases things. She is simply saying that the expansion of space causing the wavelength to expand during travel can be thought of kind of like "tired light." However, not in the static universe sense.

Is this the correct explanation for what they're both saying?
 
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