Starve.Org White Noise Usenet Archive: "Re: As Cathy Seipp Lay Dying, Her Nemesis Took His Parting Shot on the Web"

Spaceman wrote:

> "PD" <TheDraperFamily@gmail.com> wrote in message
> news:1140046447.027498.261130@z14g2000cwz.googlegroups.com...
> | That's not so, and experiment shows it.
> | What's true is velocity = wavelength * frequency.

> Sheesh PD,
> you are really lost huh?
> How do you change the wavelength without changing
> the velocity?

By changing the frequency, of course.

> | What we know is that we can recognize what frequency light was emitted
> | at, even if it is not the frequency we measure where it is received.

> How can you do that?
> How can you know what frequency was emitted if you did not actually
> measure it there?

> | (We do this with pattern recognition, but that's a separate matter.)

> No,
> it is actually not a seperate matter if you are saying it is part
> of the above and a reason you can find a frequency without
> actually measuring it.

Well, I'm glad you asked, because it is crucial to the method. The fact
is, we recognize a shifted frequency by looking at the pattern of lines
in a spectrum. The spacing of the lines is unique to each element that
radiates it. Thus, when we see a triplet of spectrographic lines (three
frequencies) that have a certain ratio between their frequencies, we
know those lines come from calcium, because *only* calcium generates a
triplet with those ratios, even if the frequencies are not the
frequencies we get from lit-up calcium in a lab on earth. And so we
know there is calcium in the star, and it is emitting frequencies at
the frequencies that calcium always emits at, and what we see is still
light from calcium, but shifted in frequency.

You might then ask, how do we know the calcium there is the same as the
calcium here? Well, the fact is that *all* the elements in a star can
be identified in exactly the same way, and after we recognize them from
the patterns of the lines, we find that the frequency shift is *exactly
the same* for all the elements.

So we have different possible scenarios:
1. The elements in the distant star are the same elements as in our own
star, but they've all been affected in that distant star -- somehow --
so that their emitted light is all at different frequencies than what
we see here, and *all affected in exactly the same way*.
And every star is affected with a different shift from star to star,
but with the same shift for all the elements in each star.
2. The elements in the distant star are not at all the same elements as
in our own star, and in fact they are completely new elements that
we've never seen before. And every star has a completely different set
of elements.
3. The distant star has the same elements as our own star, and those
elements radiate light at the same frequencies that we see those
elements radiate locally, but that it is shifted in the process of
observation.

So which of these three seems most plausible to you?

> | And we can independently measure the wavelength of that same light
> | where it is received. The product of those two numbers is always the
> | same number (c for light). Thus it cannot be that the wavelength
> | changed because the velocity changed, or that the frequency changed
> | because the velocity changed, because the velocity hasn't changed.

> The velocity of the object heading through the waves can change,
> hence the change in frequency and wavelength.
> You truly do not grasp basic doppler effect at all huh?

> I am not saying the speed of the lightsources light changed at all.
> I am talking about the object heading towards it will have a relative
> speed difference that causes the "wavelength and frequency change"

But no relative speed difference between the object and the wave has
*ever* been found for light, despite looking for it, and despite that
easily being measured for sound (independent of the Doppler shift
itself). That's what marks the difference.

> How you can not understand such basic doppler effect is beyond me.
> In short, the relative speed of the wave passing the object
> can not truly be c to such an object since if it were the wavelength and
> frequency would have no cause for change at all.