George Dishman wrote:
> "[email protected]" <[email protected]> wrote in message
> news:[email protected]
> > George Dishman wrote:
> >> [email protected] wrote:
> <snip old stuff>
> >> > Does a light source emit x photons per sec, in any given direction?
> >> Only if the brightness is constant.
> > That is a given!
> > The gun rate of fire is fixed, and no-one interferes with the source
> > luminesence.
> >> > Does the number of photons arriving at a target per time INCREASE
> >> > when the source approaches the target?
> >> No, it is still constant if the source brightness and
> >> speed of approach are constant,
> > "If my auntie had balls, she'd be my uncle"
> > There HAS BEEN an alteration, from (1) to (4).
> ... as I said in the next few words:
> >> but the number is
> >> higher than if the source wasn't approaching.
> On to other matters (you might want to read the
> bit half way down before you start replying, it
> may well supersede anything prior).
> >> effect makes the source look brighter but it doesn't
> >> change the received frequency (colour) or energy of
> >> individual photons.
> > No way!
> Yes way, If you emit 100 photons, you receive 100
> photons. If they are emitted in 1 second but received
> in 0.5 second because the source is moving towards you
> then the rate has increased from 100 p/s to 200 p/s,
> and that change means when they hit your eye you get
> a greater response, the light seems 'brighter'. That
> is a bit academic now however, the following explains
> why you haven't been following what the rest of us have
> been saying.
> > _ALL_ that is seen, is doppler blued effect, when a light
> > source alters its approach velocity to a receiver.
> Yes, I addressed that separately next.
> >> If you made an attempt to follow
> >> the conversation between Henry and myself, you
> >> would have found I said that a couple of days ago.
> > You wish to alter the numbers of photons represented, compared to
> > bullets,
> > by discussing "periods of emission"
> > Keep it simple (and true to what I say)----
> I was trying to highlight that there was a possible
> confusion of two different effects and I'm glad I did.
> > 10 bullets form either a stationary or moving (ref target) gun are
> > considered, and their energies
> > compared at the target.
> > NOTE WELL: their individual energies add to become a GROUP energy of 10
> > ONLY
> >> > DO the photons deliver MORE ENERGY?????????
> >> There is another effect called Doppler shift which you
> >> are forgetting which also operates and it does change
> >> the received frequency (colour) of each photon.
> > What is this? How does "one photon" have a frequency???????????
> Of course, that's what we have been talking about
> all the time. The energy of a _single_ photon is
> E = hv
> where h is Planck's Constant and v is the frequency
> of the _single_ photon. Look up the photoelectric
> effect and try to understand why it is convincing
> evidence for the existence of photons:
> > The FACT is, that the group of photons (equivalent to the 10 bullet
> > machine gun burst, which occurred over a fixed interval), does NOT
> > alter in number, when the source is accellerated ref the target
> The fact is that individual photons get 'blued'
> by the Doppler effect. When we measure the
> spectrum of a star with a grating and a CCD,
> each photon that hits a pixel on the CCD adds
> a small charge that is stored in the pixel.
> At the end of the exposure, the total charge
> is read out and it tells us the number of
> photons that hit the pixel. The photons arrive
> from the star all travelling in the same
> direction but they bounce of the grating at
> different angles depending on their individual
> frequency, so they land on different pixels.
> The set of charge values is then a histogram
> of the number of photons in a small band of
> wavelengths (hence frequencies since the
> photons from a single source all have the
> same speed whether that speed is c or not).
> The fact is that for the last couple of months
> Henry, Jeff and I have all been discussing the
> burst of gunfire as representing a _single_
> photon and showing how Doppler effect in
> ballistic theory would change the frequency of
> that one photon by changing the bullet hit rate
> compared to the firing rate.
> Now in this latest few posts, you seem to have
> changed to talking of each photon being a bullet
> which is not unreasonable but is a different way
> of looking at it compared to what has been said
> up to now.
> > You say somewhere that I compare a SINGLE photon, as to a group of
> > bullets;
> You started the thread by talking about the
> Doppler effect so that is what the rest of us
> have been discussing for the last two months,
> the Doppler effect changes the frequency of
> individual photons.
> Just a few days ago, I said a single photon
> should be represented by a burst of fixed
> duration. You didn't say that was wrong and
> you suggested that instead it should be a
> burst with a fixed number of bullets so you
> still appeared to be thinking along the same
> > get this right, and for good!
> > ONE bullet, or ONE photon (see footnote) does not have a frequency, ...
> The whole of Planck's resolution of black body
> radiation was that each individual photon has a
> frequency and carries an amount of energy which
> is proportional to that frequency. Einstein was
> awarded the Nobel prize for his work on the
> photoelectric effect which confirmed that
> hypothesis experimentally and it remains a
> fundamental piece of evidence for the existence
> of photons. The Doppler effect changes that
> > ... so
> > that suggestion
> > highlights how far you are prepared to go, in order to misrepresent my
> > position
> I assumed you knew that a single photon has a
> frequency since it is so fundamental to the whole
> subject, and you haven't said anything to the
> contrary since we started discussing this at the
> end of January. The Doppler effect changes the
> frequency of a single photon which is what was
> being discussed up to a few days so I wasn't
> 'misrepresenting' anything.
I doubt that Henri misunderstood my position (that the ten bullets were
and considered as analogous), as to ten photons.
As for photon energy; one photon DOES have its individual energy, as
does one bullet.
However, ONE photon does NOT have a frequency when considered
Does one pressure front in a sound through a medium have a frequency?
Of course not!
A single gun shot has NO frequency, but a burst DOES.
Similarly, a procession of photons have a frequency, and our eye/brain
construe this as light. Photons have been (sic almost) stopped in the
lab)-- what was their frequency when stopped?
And I agree that the faster group of photons (due to increased
target/source closing speed), WOULD be brighter, BECAUSE it is more
energetic (both for individual photons, and the group)