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Index of Subjects
>>> been able to devise for it as the technology to do so
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Light is not affected by either electrical or magnetic fields These fields =
follow "linearity" which means that when the electric and magnetic fields t=
hat make up light pass through an area with either a magnetic or electric f=
ield, in the local area where the light passes the fields are added togethe=
r but they do not actually interact. They are affected by gravity (in fact =
this was the first test of relativity where the experiment showed that the =
bending of starlight was exactly as predicted. (On a side note, the surface=
gravity of a neutron star is so strong (escape velocity is over half that =
of light!) that light leaving the surface at an angle, rather than straight=
up, bends back down to the surface That lets you "see" about 2/3 of the su=
rface from your location. I worked it out for the Earth and if light did th=
e same thing here, you could stand on Citadel Hill, look south, and Buenos =
Aires would be on your horizon!)
Spectral lines (caused by absorption of light by the energy levels of atoms=
or molecules) can be quite thin, but their are reasons they can be wider. =
One is rotational broadening (part of the star producing the line is rotati=
ng towards you, and part is moving away, so the wavelengths are spread out =
by the Doppler effect. It is possible to actually work out the rotation rat=
e of the star. Broadening can also occur depending on the density and press=
ure of the gas. Both of these effects tend to be subtle but they can be ob=
served. Here is a typical profile caused by hydrogen gas when seen in absor=
ption in front of a blackbody.
https://astronomy.com/magazine/ask-astro/2019/06/how-do-scientists-determin=
e-the-chemical-compositions-of-the-planets-and-stars
On another note, I did find a good explanation on why light has momentum:
https://wtamu.edu/~cbaird/sq/2014/04/01/light-has-no-mass-so-it-also-has-no=
-energy-according-to-einstein-but-how-can-sunlight-warm-the-earth-without-e=
nergy/
(It was this equation, which simplifies to E =3D m x c^2 that is the more f=
amous version. It was also the fact that you need to take the square root o=
f both sides that lead Paul Dirac to postulate the existence of antimatter,=
since the square root of 9 is both +3 and -3. He predicted, in 1928, the p=
ossibility of an anti-matter counterpart to the electron. In 1932 the first=
positrons were discovered. Dirac and Erwin Schr=F6dinger shared the 1932 N=
obel Prize in Physics.)
Pat
On May 22, 2020, at 12:08 PM, David Webster wrote:
CAUTION: The Sender of this email is not from within Dalhousie.
Hi Patrick & All,
Thanks for the further explanation.
Light is of course refracted when entering or leaving a medium of diffe=
rent refractive index at an angle but so far as I am aware no energy is los=
t if the refracting medium is transparent.
But many quantitative chemical determinations are based on absorption o=
f light, usually by substances in liquid solution but, given suitable condi=
tions (e.g. Atomic absorption spectroscopy) this may apply also to some sus=
pensions in gas.
When absorption is used for quantitative analysis one is interested onl=
y in the decrease in intensity at a specific wavelength and filters are nor=
mally placed between source and target. But if source light were not filter=
ed would there usually be an abrupt drop in intensity at the absorbed wavel=
ength or a gradual decrease to a minimum ?
Does light in any way interact with gradients of electrical potential o=
r magnetic fields ? Or expressed another way modified by them ?
I have read that light has no mass but has momentum. Because momentum i=
s usually defined as mass x velocity how can there be momentum at zero mass=
?
Yt, DW, Kentville
On 5/21/2020 3:58 PM, Patrick Kelly wrote:
Interference won't work either. Unlike water waves, which travel in a mediu=
m, which can physically interact, light waves do not travel through a mediu=
m at all, so they pass by and through each other with no effect.
(In the last 1800s, Michaelson and Morley devised an experiment to look for=
the "aether" though which it was though that light propogated. Their exper=
iment proved there is no such thing.
https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment)
You can get waves to interfere with each other if they come from a single s=
ource and pass though a narrow slit, and then a double slit, but the constr=
uctive and destructive only occurs in a limited area, and affects their amp=
litude, not their wavelength. Plus, the size of the slip would only affect =
waves of a certain wavelength. You can prove this to yourself at a beach. T=
ake a whole bunch of stick, and line them up in a row parallel to the shore=
. Space them about 3 or 4 wavelength apart. The waves will just ignore them=
. If you keep filling it to get the gaps close to the size of the wavelengt=
h you will then see some interference and if you take lots of sticks and ma=
ke the gaps a lot smaller than the wavelength, you will see that the waves =
will now reflect off the barrier. (That is why radio telescopes can be made=
with, what looks like chain link fencing material. The wavelength of radio=
waves is sol long compared to the gaps that they just see it as a smooth s=
urface.
The other problem is that at the large scale the structure of the matter in=
the universe is "frothy" like soap bubbles with large voids with almost no=
galaxies, and galaxies found in sheets, filaments and lumped together in c=
luster and supercluster where these come together. So any process that depe=
nds on light interacting with matter, would have to produce identical effec=
ts on electromagnetic radiation of all wavelengths, coming through all man=
ner of distributions of matter AND give results that are exactly the same a=
s those of an expanding universe which is predicted by relativity, a theory=
which has passed (perfectly) every test we have been able to devise for it=
as the technology to do so has advanced.
Humans used to be comfortable with the idea that Earth was at the centre of=
everything. Turned out we aren't but then we though we were near the centr=
e of the Milky Way. It turned out that we aren't but we though that we were=
in the only galaxy. Turned out we aren't, there are billions of them. Scie=
nce does not care about what makes humans feel good.....
The universe also is highly unlikely to have perpetual renewal. There was a=
time when it was though that there was enough matter (including dark matte=
r) to eventually slow the expansion. That is no longer the case. The rate o=
f expansion appears to be increasing due to dark energy. This is an outward=
"pressure" that appears to be a property of space-time (Einstein's cosmolo=
gical constant that he later though was zero) and the universe expands, the=
re are more and more cubic metres from which the dark energy can act. The e=
ventual result is the heat death of the universe.
There are already large prats (the vast majority, actually) of the universe=
which is unobservable to us. As the expansion rate continues, more and mor=
e distant objects will disappear. Almost all regular matter in the universe=
is in the form of stars or gas and dust. For the vast majority of stars (i=
ncluding the Sun), at the end of their life they puff off a bit of their ou=
ter atmosphere and end up as a white dwarf star. They can no longer produce=
energy and slowly cool off becoming black dwarves. They are quite small=85=
the mass of the Sun packed into a ball the size of Earth and kept from col=
lapsing farther by electron degeneracy pressure.
For the small number of stars about 2-10 times the mass of the sun, they en=
d up producing a supernova explosion, throwing some material back into spac=
e with the rest ending up as a neutron star. Again, they can no longer prod=
uce energy and slowly cool off becoming black. They are even smaller=85 the=
mass of the Sun (or a bit more) packed into a ball the size of Halifax and=
kept from collapsing farther by neutron degeneracy pressure.
The really massive stars end up as black holes as they have so much leftove=
r mass that neutron degeneracy pressure cannot stop the collapse. On the lo=
w end they produce supernova and end up as a black hole=85 on the high end =
they simply wink out leaving behind a black hole.
So all stars end up as a dead object that either slowly cools off, or in th=
e cases of black holes go cold right from the start. You can always make mo=
re stars, but there you run into a problem. You need gas* and dust** from w=
hich to form them.
About 25% of the galaxies are classed as elliptical. They used up all their=
gas and dust in a massive burst of star formation when they formed. As the=
stars in there galaxies "turn off" they cannot be replaced. The Milky Way =
is classed as a spiral galaxy and about 70% of galaxies fall into this type=
. About 15% of their mass is still in the form of gas and dust, so they, at=
least for now, they are capable of forming new stars, but a time will come=
when they too run out of gas and dust. About 5% of galaxies are "irregular=
" and while they have about 50% of their mass in gas and dust they are quit=
e small. It is though that many of them formed from collisions between spir=
al galaxies (common in clusters) an the stars are so far apart they can eas=
ily pass through each other, the same cannot be said of clouds of gas. They=
are also undergoing massive star formation, likely due to the shock waves =
in the gas caused by the encounter.
So, in the grad scheme of things, a bit depressing, but as there are still =
many billions of years to go, I would not be too worried about it, especial=
ly as the Sun is going to fry the earth in about 4 billion years when it go=
es through its red giant phase.....
Pat
*The gas in our galaxy is 97% hydrogen and helium, with the other 3% compos=
ed of metal. Note that in astronomy, "metal" is the term used for all the c=
hemical elements which are neither hydrogen nor helium.. The early universe=
started with no metal. Again, observed in the early universe, and predicte=
d by the Big Bang Theory.
** Dust is mostly carbon with some water ice and other molecules and accoun=
ts for only 1% of the mass of the "gas and dust"
On May 15, 2020, at 9:54 PM, David Webster wrote:
CAUTION: The Sender of this email is not from within Dalhousie.
Hi Steve & All,
As I indicated earlier, my physics at this juncture mostly
revolves around a diet rich in plant fiber. But getting back to 'tired
light' if you wish to call it that--- I agree that interaction with
particles does not wash.
But I wonder about destructive interference. When two waves are out
of phase the resultant is zero. An observer sees only that light emitted
by the near surface but, in general, light will be emitted in all
directions by a spherical luminous body. And light from the most
distant source will have the greatest opportunity to experience
interference, in transit, and light from less distant sources will have
progressively less opportunity.
Or, expressed in greater detail, if there are many light sources,
which is the case, then light from more distant sources must be exposed
in transit to more light from sources which are less distant and
consequently have greater opportunity to experience destructive
interference and this will preferentially have least effect at the red
end (lower frequency) and greatest effect at the blue end (higher
frequency) of the spectrum. So there will be a red shift which increases
with distance from observer.
I am more comfortable with a universe which does not expand because
1) the universe as we know it, from observation, is well adapted to
perpetual renewal, 2) I find it difficult to imagine a time when the
universe did not exist, except as a infinitely dense something which for
no clear reason decided to blow up to become ever larger. 3) Although
history is important and interesting, and Astrophysics and related
topics are fun, the pressing issues ahead revolve around Climate Change;
how to get past the empty promise stage and take coordinated action with
trade penalties for slackers.
Yt, DW, Kentville
On 5/15/2020 7:48 PM, Stephen Shaw wrote:
Dave: see salutary account of this idea under "Tired Light=94 in Wikipedia =
(always 100% reliable, as you know).
Quoting:
"By the 1990s and on into the twenty-first century, a number of falsifying =
observations have shown that "tired light" hypotheses are not viable explan=
ations for cosmological redshifts.=94
A good read therein and a quite complicated analysis: refutation is based n=
ot just on thought experiments or theory, but on some contrary astronomical=
observations that you have to surmount in order to continue to argue for a=
tired light explanation of cosmological redshifts.
On May 15, 2020, at 4:57 PM, David Webster <dwebster@glinx.com<mailto:dwebs=
ter@glinx.com>> wrote
Hi Patrick & All,
Thanks Patrick for the detailed explanation of the Big Bang. In
bare outline the Hubble Constant, amount of red shift is proportional to
distance between source and observer, and this is taken as proof that
the universe is expanding. But is an expanding universe the only way to
account for these observations ?
Experience with the properties of light from nearby sources has led
to the assumption that light, an electromagnetic wave, can travel
billions of years through magnetic fields, or electric fields without
modification or loss of energy. But how can one be sure that light can
travel for billions of years without some consumption or loss of
photon/wave energy ?
The objection that no attrition of photon energy over time,
regardless of medium properties or travel time, is know to occur is not
valid because the Hubble effect might be due to such attrition and not
an expanding universe.
And, with math proficiency degraded by moth, time and rust to
about grade 8 level I am not in any position to debate this subject.
Just express doubts about interpretation.
But falling back on an old saying, as a Parthian shot; "Discovery
is seeing what everyone else has seen and thinking what no one else has
thought."
Yt, DW, Kentville
Patrick Kelly
159 Town Road
Falmouth NS B0P 1L0
Canada
(902) 472-2322
Patrick Kelly
159 Town Road
Falmouth NS B0P 1L0
Canada
(902) 472-2322
--_000_E83FC6868D0B426EA4F31A453CC408D3dalca_
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252">
</head>
<body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-lin=
e-break: after-white-space; ">
<div>Light is not affected by either electrical or magnetic fields These fi=
elds follow "linearity" which means that when the electric and ma=
gnetic fields that make up light pass through an area with either a magneti=
c or electric field, in the local area where
the light passes the fields are added together but they do not actually in=
teract. They are affected by gravity (in fact this was the first test of re=
lativity where the experiment showed that the bending of starlight was exac=
tly as predicted. (On a side note,
the surface gravity of a neutron star is so strong (escape velocity is ove=
r half that of light!) that light leaving the surface at an angle, rather t=
han straight up, bends back down to the surface That lets you "see&quo=
t; about 2/3 of the surface from your location.
I worked it out for the Earth and if light did the same thing here, you co=
uld stand on Citadel Hill, look south, and Buenos Aires would be on your ho=
rizon!)</div>
<div><br>
</div>
<div>Spectral lines (caused by absorption of light by the energy levels of =
atoms or molecules) can be quite thin, but their are reasons they can be wi=
der. One is rotational broadening (part of the star producing the line is r=
otating towards you, and part is
moving away, so the wavelengths are spread out by the Doppler effect. It i=
s possible to actually work out the rotation rate of the star. Broadening c=
an also occur depending on the density and pressure of the gas. Both of the=
se effects tend to be subtle but
they can be observed. Here is a typical profile caused by hydrogen g=
as when seen in absorption in front of a blackbody.</div>
<div><br>
</div>
<div><a href=3D"https://astronomy.com/magazine/ask-astro/2019/06/how-do-sci=
entists-determine-the-chemical-compositions-of-the-planets-and-stars">https=
://astronomy.com/magazine/ask-astro/2019/06/how-do-scientists-determine-the=
-chemical-compositions-of-the-planets-and-stars</a></div>
<div><br>
</div>
<div>On another note, I did find a good explanation on why light has moment=
um:</div>
<div><br>
</div>
<div><a href=3D"https://wtamu.edu/~cbaird/sq/2014/04/01/light-has-no-mass-s=
o-it-also-has-no-energy-according-to-einstein-but-how-can-sunlight-warm-the=
-earth-without-energy/">https://wtamu.edu/~cbaird/sq/2014/04/01/light-has-n=
o-mass-so-it-also-has-no-energy-according-to-einstein-but-how-can-sunlight-=
warm-the-earth-without-energy/</a></div>
<div><br>
</div>
<div>(It was this equation, which simplifies to E =3D m x c^2 that is the m=
ore famous version. It was also the fact that you need to take the square r=
oot of both sides that lead Paul Dirac to postulate the existence of antima=
tter, since the square root of 9 is
both +3 and -3. He predicted, in 1928, the possibility of an anti-matt=
er counterpart to the electron. In 1932 the first positrons were discovered=
. Dirac and Erwin Schr=F6dinger shared the 1932 Nobel Prize in Physics=
.)</div>
<div><br>
</div>
<div>Pat</div>
<div><br>
</div>
<div><br>
</div>
<div>
<div>On May 22, 2020, at 12:08 PM, David Webster wrote:</div>
<br class=3D"Apple-interchange-newline">
<blockquote type=3D"cite">
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text-align:left;color:#ffffff;">
<span style=3D"font-weight:bold;font-size:12px;">CAUTION:</span> The Sender=
of this email is not from within Dalhousie.</div>
</td>
</tr>
</tbody>
</table>
</td>
</tr>
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</table>
</td>
</tr>
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<div>
<p>Hi Patrick & All,</p>
<p> Thanks for the further explanation. <br>
</p>
<p> Light is of course refracted when entering or leaving=
a medium of different refractive index at an angle but so far as I am awar=
e no energy is lost if the refracting medium is transparent.
<br>
</p>
<p> But many quantitative chemical determinations are bas=
ed on absorption of light, usually by substances in liquid solution but, gi=
ven suitable conditions (e.g. Atomic absorption spectroscopy) this may appl=
y also to some suspensions in gas.
<br>
</p>
<p> When absorption is used for quantitative analysis one=
is interested only in the decrease in intensity at a specific wavelength a=
nd filters are normally placed between source and target. But if source lig=
ht were not filtered would there usually be an
abrupt drop in intensity at the absorbed wavelength or a gradual decrease =
to a minimum ?<br>
</p>
<p> Does light in any way interact with gradients of elec=
trical potential or magnetic fields ? Or expressed another way modifi=
ed by them ?
<br>
</p>
<p> I have read that light has no mass but has momentum. =
Because momentum is usually defined as mass x velocity how can there be mom=
entum at zero mass ?
<br>
</p>
<p>Yt, DW, Kentville<br>
</p>
<div class=3D"moz-cite-prefix">On 5/21/2020 3:58 PM, Patrick Kelly wrote:<b=
r>
</div>
<blockquote type=3D"cite" cite=3D"mid:662E3D62-D8C0-4C61-B811-727C09E501F9@=
dal.ca">Interference won't work either. Unlike water waves, which travel in=
a medium, which can physically interact, light waves do not travel through=
a medium at all, so they pass by and
through each other with no effect.
<div><br>
</div>
<div>(In the last 1800s, Michaelson and Morley devised an experiment to loo=
k for the "aether" though which it was though that light propogat=
ed. Their experiment proved there is no such thing.
<div><br>
</div>
<div>
<div><a href=3D"https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_expe=
riment" moz-do-not-send=3D"true">https://en.wikipedia.org/wiki/Michelson%E2=
%80%93Morley_experiment</a>)</div>
<div><br>
</div>
<div>You can get waves to interfere with each other if they come from a sin=
gle source and pass though a narrow slit, and then a double slit, but the c=
onstructive and destructive only occurs in a limited area, and affects thei=
r amplitude, not their wavelength.
Plus, the size of the slip would only affect waves of a certain wavelength=
. You can prove this to yourself at a beach. Take a whole bunch of stick, a=
nd line them up in a row parallel to the shore. Space them about 3 or 4 wav=
elength apart. The waves will just
ignore them. If you keep filling it to get the gaps close to the size of t=
he wavelength you will then see some interference and if you take lots of s=
ticks and make the gaps a lot smaller than the wavelength, you will see tha=
t the waves will now reflect off
the barrier. (That is why radio telescopes can be made with, what looks li=
ke chain link fencing material. The wavelength of radio waves is sol long c=
ompared to the gaps that they just see it as a smooth surface.</div>
<div><br>
</div>
<div>The other problem is that at the large scale the structure of the matt=
er in the universe is "frothy" like soap bubbles with large voids=
with almost no galaxies, and galaxies found in sheets, filaments and lumpe=
d together in cluster and supercluster where
these come together. So any process that depends on light interacting with=
matter, would have to produce identical effects on electromagnetic radiati=
on of all wavelengths, coming through all manner of distributions of =
matter AND give results that are exactly
the same as those of an expanding universe which is predicted by relativit=
y, a theory which has passed (perfectly) every test we have been able to de=
vise for it as the technology to do so has advanced.</div>
<div><br>
</div>
<div>Humans used to be comfortable with the idea that Earth was at the cent=
re of everything. Turned out we aren't but then we though we were near the =
centre of the Milky Way. It turned out that we aren't but we though that we=
were in the only galaxy. Turned
out we aren't, there are billions of them. Science does not care about wha=
t makes humans feel good.....</div>
<div><br>
</div>
<div>The universe also is highly unlikely to have perpetual renewal. There =
was a time when it was though that there was enough matter (including dark =
matter) to eventually slow the expansion. That is no longer the case. The r=
ate of expansion appears to be increasing
due to dark energy. This is an outward "pressure" that appears t=
o be a property of space-time (Einstein's cosmological constant that he lat=
er though was zero) and the universe expands, there are more and more cubic=
metres from which the dark energy can act.
The eventual result is the heat death of the universe. </div>
<div><br>
</div>
<div>There are already large prats (the vast majority, actually) of the uni=
verse which is unobservable to us. As the expansion rate continues, more an=
d more distant objects will disappear. Almost all regular matter in the uni=
verse is in the form of stars or
gas and dust. For the vast majority of stars (including the Sun), at the e=
nd of their life they puff off a bit of their outer atmosphere and end up a=
s a white dwarf star. They can no longer produce energy and slowly cool off=
becoming black dwarves. They are
quite small=85 the mass of the Sun packed into a ball the size of Earth an=
d kept from collapsing farther by electron degeneracy pressure.</div>
<div><br>
</div>
<div>For the small number of stars about 2-10 times the mass of the sun, th=
ey end up producing a supernova explosion, throwing some material back into=
space with the rest ending up as a neutron star. Again, they can no longer=
produce energy and slowly cool
off becoming black. They are even smaller=85 the mass of the Sun (or a bit=
more) packed into a ball the size of Halifax and kept from collapsing fart=
her by neutron degeneracy pressure.</div>
<div><br>
</div>
<div>The really massive stars end up as black holes as they have so much le=
ftover mass that neutron degeneracy pressure cannot stop the collapse. On t=
he low end they produce supernova and end up as a black hole=85 on the high=
end they simply wink out leaving
behind a black hole.</div>
<div><br>
</div>
<div>So all stars end up as a dead object that either slowly cools off, or =
in the cases of black holes go cold right from the start. You can always ma=
ke more stars, but there you run into a problem. You need gas* and dust** f=
rom which to form them. </div>
<div><br>
</div>
<div>About 25% of the galaxies are classed as elliptical. They used up all =
their gas and dust in a massive burst of star formation when they formed. A=
s the stars in there galaxies "turn off" they cannot be replaced.=
The Milky Way is classed as a spiral galaxy
and about 70% of galaxies fall into this type. About 15% of their mass is =
still in the form of gas and dust, so they, at least for now, they are capa=
ble of forming new stars, but a time will come when they too run out of gas=
and dust. About 5% of galaxies
are "irregular" and while they have about 50% of their mass in g=
as and dust they are quite small. It is though that many of them formed fro=
m collisions between spiral galaxies (common in clusters) an the stars are =
so far apart they can easily pass through
each other, the same cannot be said of clouds of gas. They are also underg=
oing massive star formation, likely due to the shock waves in the gas cause=
d by the encounter.</div>
<div><br>
</div>
<div>So, in the grad scheme of things, a bit depressing, but as there are s=
till many billions of years to go, I would not be too worried about it, esp=
ecially as the Sun is going to fry the earth in about 4 billion years when =
it goes through its red giant phase.....</div>
<div><br>
</div>
<div>Pat</div>
<div><br>
</div>
<div>*The gas in our galaxy is 97% hydrogen and helium, with the other 3% c=
omposed of metal. Note that in astronomy, "metal" is the term use=
d for all the chemical elements which are neither hydrogen nor helium.. The=
early universe started with no metal. Again,
observed in the early universe, and predicted by the Big Bang Theory.</div=
>
<div><br>
</div>
<div>** Dust is mostly carbon with some water ice and other molecules and a=
ccounts for only 1% of the mass of the "gas and dust"</div>
<div> </div>
<div><br>
</div>
<div><br>
<div>
<div>On May 15, 2020, at 9:54 PM, David Webster wrote:</div>
<br class=3D"Apple-interchange-newline">
<blockquote type=3D"cite">
<div>CAUTION: The Sender of this email is not from within Dalhousie.<br>
<br>
Hi Steve & All,<br>
<br>
As I indicated earlier, my physics at this juncture=
mostly<br>
revolves around a diet rich in plant fiber. But getting back to 'tired<br>
light' if you wish to call it that--- I agree that interaction with<br>
particles does not wash.<br>
<br>
But I wonder about destructive interference. When two wav=
es are out<br>
of phase the resultant is zero. An observer sees only that light emitted<br=
>
by the near surface but, in general, light will be emitted in all<br>
directions by a spherical luminous body. And light from the most<br>
distant source will have the greatest opportunity to experience<br>
interference, in transit, and light from less distant sources will have<br>
progressively less opportunity.<br>
<br>
Or, expressed in greater detail, if there are many light =
sources,<br>
which is the case, then light from more distant sources must be exposed<br>
in transit to more light from sources which are less distant and<br>
consequently have greater opportunity to experience destructive<br>
interference and this will preferentially have least effect at the red<br>
end (lower frequency) and greatest effect at the blue end (higher<br>
frequency) of the spectrum. So there will be a red shift which increases<br=
>
with distance from observer.<br>
<br>
I am more comfortable with a universe which does not expa=
nd because<br>
1) the universe as we know it, from observation, is well adapted to<br>
perpetual renewal, 2) I find it difficult to imagine a time when the<br>
universe did not exist, except as a infinitely dense something which for<br=
>
no clear reason decided to blow up to become ever larger. 3) Although<br>
history is important and interesting, and Astrophysics and related<br>
topics are fun, the pressing issues ahead revolve around Climate Change;<br=
>
how to get past the empty promise stage and take coordinated action with<br=
>
trade penalties for slackers.<br>
<br>
Yt, DW, Kentville<br>
<br>
On 5/15/2020 7:48 PM, Stephen Shaw wrote:<br>
<blockquote type=3D"cite">Dave: see salutary account of this idea under &qu=
ot;Tired Light=94 in Wikipedia (always 100% reliable, as you know).<br>
</blockquote>
<blockquote type=3D"cite">Quoting:<br>
</blockquote>
<blockquote type=3D"cite">"By the 1990s and on into the twenty-first c=
entury, a number of falsifying observations have shown that "tired lig=
ht" hypotheses are not viable explanations for cosmological redshifts.=
=94<br>
</blockquote>
<blockquote type=3D"cite"><br>
</blockquote>
<blockquote type=3D"cite">A good read therein and a quite complicated analy=
sis: refutation is based not just on thought experiments or theory, but on =
some contrary astronomical observations that you have to surmount in order =
to continue to argue for a tired light
explanation of cosmological redshifts.<br>
</blockquote>
<blockquote type=3D"cite"><br>
</blockquote>
<blockquote type=3D"cite">On May 15, 2020, at 4:57 PM, David Webster <<a=
href=3D"mailto:dwebster@glinx.com" moz-do-not-send=3D"true">dwebster@glinx=
.com</a>> wrote<br>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">Hi Patrick & All,<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"> Thanks Patrick for the detailed=
explanation of the Big Bang. In<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">bare outline the Hubble Constant, amount of red s=
hift is proportional to<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">distance between source and observer, and this is=
taken as proof that<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">the universe is expanding. But is an expanding un=
iverse the only way to<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">account for these observations ?<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"> Experience with the properties of lig=
ht from nearby sources has led<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">to the assumption that light, an electromagnetic =
wave, can travel<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">billions of years through magnetic fields, or ele=
ctric fields without<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">modification or loss of energy. But how can=
one be sure that light can<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">travel for billions of years without some consump=
tion or loss of<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">photon/wave energy ?<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"> The objection that no attrition=
of photon energy over time,<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">regardless of medium properties or travel time, i=
s know to occur is not<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">valid because the Hubble effect might be due to s=
uch attrition and not<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">an expanding universe.<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"> And, with math proficienc=
y degraded by moth, time and rust to<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">about grade 8 level I am not in any position to d=
ebate this subject.<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">Just express doubts about interpretation.<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"> But falling back on an old sayi=
ng, as a Parthian shot; "Discovery<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">is seeing what everyone else has seen and thinkin=
g what no one else has<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">thought."<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite">Yt, DW, Kentville<br>
</blockquote>
</blockquote>
<blockquote type=3D"cite">
<blockquote type=3D"cite"><br>
</blockquote>
</blockquote>
</div>
</blockquote>
</div>
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