Tired light and supernovae

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by EBTX</i>
This is also true in tired light models for someone truly receding from you. However, tired light models do not posit that cosmological redshift is related to velocity but rather to absorption of some of the light's energy in the intervening space. Hence, a signal from such a source should appear to be redshifted but ... the total time over which the signal is sent will not be lengthened.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
This conclusion is actually incorrect. It is a simple mathematical consequence of the addition theorem for trigonometric functions that, if a redshift exists at all, supernova lightcurves for instance should be broadened as well (see my post in the sci.astro.research newsgroup ; Ned Wright and the group moderator tried to invalidate this proof with the argument that a redshift must always be associated with a recession of the galaxy in order to 'accommodate' the full number of cycles of the electromagnetic wave, but this argument does only hold for a coherent sinusoidal wave but not for short wavetrains).

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The "'accommodate' the full number of cycles" detail is a good point to model. NW has a great issue here for sure. This detail may be very important in resolving at least part of the problem of developing a different explaination for Hubble redshift(other than an expanding universe). My perspective on this issue is the Hubble shift is caused by gravity and is observed on a local scale as well as cosmic scale. The accommodation of the cycles is done as it is done in any gravity induced redshift. Just explain how it is done in gravity fields.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />It is a simple mathematical consequence of the addition theorem for trigonometric functions that, if a redshift exists at all, supernova lightcurves for instance should be broadened as well...; Ned Wright and the group moderator tried to invalidate this proof...<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">I hate to agree with New Wright about anything. But in this case, I'm afraid I must.

Instead of thinking of a wave train and frequencies and redshifts, just think about a single photon released from a supernova at time t1 and traveling to Earth. Suppose it arrives at time E1. One week later, another independent photon is released from the same supernova at time t2 and makes the same journey. Suppose it arrives on Earth at time E2.

Now if the supernova is moving away from us at high speed, then the second photon has farther to travel, so (E2-E1) will be greater than (t2-t1). But if the distance of the supernova has not changed, and the light is redshifting through some energy loss mechanism (any mechanism will do), then the travel time of every independent photon should be the same, and (E2-E1) will be the same as (t2-t1).

To make the time intervals unequal would require changing something along the path during the time interval between the release of the two photons. Perhaps you wish to hypothesize that the speed of light is slowing down throughout the universe, and for that reason the second photon travels at a slower speed than the first. But I think the simplest explanation is the one I gave in this thread. Brightness is used as an arbiter for estimating how broad each ltghtcurve ought to be by assuming the BB redshift-distance law, which is wrong. When the correct redshift-distance law is used, supernova lightcurves no longer appear to be broader with increasing redshift. -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
Instead of thinking of a wave train and frequencies and redshifts, just think about a single photon released from a supernova at time t1 and traveling to Earth. Suppose it arrives at time E1. One week later, another independent photon is released from the same supernova at time t2 and makes the same journey. Suppose it arrives on Earth at time E2.
Now if the supernova is moving away from us at high speed, then the second photon has farther to travel, so (E2-E1) will be greater than (t2-t1). But if the distance of the supernova has not changed, and the light is redshifting through some energy loss mechanism (any mechanism will do), then the travel time of every independent photon should be the same, and (E2-E1) will be the same as (t2-t1).<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
There is no problem with this because the travel time of the photons has nothing to do with the broadening of the lightcurve (in a static universe). The latter does not mean that we are observing a shorter period of the physical event in a given time but that the amplitudes become relatively compressed as the (uncorrelated) wave trains (photons) are stretched (redshifted) (see my schematic illustration below).

<center> </center>


Note: This drawing is actually not quite correct because the z=1 lightcurve should be below the z=0 curve all the way through (by a compression factor 1/2) (I just drew it this way because it was easier to get the slopes right).
Of course the reduction in amplitude of the curve would have to be taken into account when determining the broadening factor (because otherwise the absolute brightness of the supernova would be determined incorrectly), but this does not affect the basic validity of my argument (as far as I have seen, present data have anyway still rather large uncertainties and do really not show much more than the existence of *some* correlation between redshift factor and lightcurve broadening).

---

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The following is a meeting report that I just received in email. It seems especially relevant to this thread, so I report it here. -|Tom|-

&gt; From: "J Kierein" &lt;jkierein@lycos.com&gt;

I have returned from the American Physical Society's astrophysics meeting in Denver. I attended a talk where supernova -in particular, SN 1A, - time dilation evidence was discussed in great detail. The upshot is that the speaker, Jerry W. Jensen, said there is no such evidence.

This is critical for deciding if there was a big bang. Time dilation can be said to be the following: If the SN 1A is moving away at a high redshift, then the light curve should be spread the same as the red shift, with some corrections. The light curve is the time it takes for a SN to brighten and decay to its original brightness.

For example, if the red shift is Z = 1, then the SN is travelling away at nearly the speed of light and if the intrinsic light curve is typically 30 days, then the last light should be coming from a distance nearly 30 light days farther away and should arrive 30 days later than if the SN was not travelling away at such a high velocity. The light curve should nearly double to 60 days. (Actually it can be shown relativistically that the light curve should be exactly the red shift stretch, with some reduction due to the dimming associated with the lowering of the photon flux due to the
velocity.) The stretching of the light curve is referred to as time dilation.

SN 1A's are of particular interest because they can be treated as near standard candles and provide a somewhat good way to estimate distance.

The speaker reviewed the data where time dilation was claimed based on the relatively few observations available. He disagreed with the time dilation claim. The SN 1A light curves vary significantly from nearby observations, with some as short as 20 days and others as long as 60 days.

He showed that there is a well observed relation between the time length of the SN 1A curve and the brightness of the SN, with the brighter SN having longer light curves. He showed that the selection effect should be that the brighter SN 1A should be preferentially observed at the greater Z of greater distance simply because it is brighter. He used terms such as the previos author (Goldhaber) not making allowance for Malmquist bias. Basically his argument was (as I understand it), that the brighter SN have an intrinsically longer light curve and they should show up more than the dimmer SN at larger red shift and that the data from his analysis shows not only that time dilation cannot be claimed but that actually THERE IS NO TIME DILATION!

This is very significant, because if the SN have no time dilation, it means they are not travelling away as their red shift would indicate. They must have an intrinsic non-doppler red shift. Of course, if the SN have no doppler red shift, then the big bang is in big trouble. This opens the door to other red shifts not being doppler such as the quasar red shift.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Thomas</i>
<br />There is no problem with this because the travel time of the photons has nothing to do with the broadening of the lightcurve (in a static universe).<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Please think about what you just said. It cannot be correct.

If photon 1 is emitted at the instant of maximum supernova brightness (t1), and photon 2 is emitted at the instant when the lightcurve falls to half-maximum brightness (t2), then the time interval (t2-t1) is set at the source (assumed to be a fixed distance away), and cannot change anywhere along the journey to Earth unless the speed of photon 2 is different than the speed of photon 1. And if nothing affects the brightness of the two photons differently, the lightcurve (brightness vs. time) will be perfectly preserved regardless of any changes in wavelength or frequency.

Whether either photon is redshifted at all, or by how much, is irrelevant to their travel times. Think of the Sun being the supernova (for thought purposes only! [}]). Wavelength and frequency can change without affecting the speed of light. And only something that does affect the travel times can affect the time stretching of the lightcurve. -|Tom|-