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Do POV photons have mass? ;)
Does ANYTHING in POV have mass? heehe
POV ver. 9; significant for its introduction of simulation of
Higgs field interaction with light sources...
YKYBRTALNTANPATLW...?
--
Tim Cook
http://empyrean.scifi-fantasy.com
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------
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> Do POV photons have mass? ;)
>
> Does ANYTHING in POV have mass? heehe
Wasn't there a thread 'bout a relativistic raytracer ? ...
I'm sure someone has the link to the animations, of this
raytracers, that does a red/blueshift when in motion ...
> POV ver. 9; significant for its introduction of simulation of
> Higgs field interaction with light sources...
you mean photons won't always fly straight, but be affected by
the mass of objects ? I can think of easier ways of doing a blackhole
> YKYBRTALNTANPATLW...?
^ ^^^^^^^^^
--
Jan Walzer <jan### [at] lzer net>
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Timothy R. Cook <tim### [at] scifi-fantasycom> wrote:
: Does ANYTHING in POV have mass? heehe
POV only simulates infinitely thin surfaces. Such surfaces can't have mass.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Jan Walzer <jan### [at] lzernet> wrote:
: you mean photons won't always fly straight, but be affected by
: the mass of objects ?
In fact, photons do always "fly" straight.
Of course the meaning of "straight" is actually "the shortest path between
two points in space". In a cartesian coordinate system this is what we usually
think as "a straight line". However, according to the theory, space is not
a cartesian coordinate system, but it's bent due to masses in it. In this kind
of curved space the real shortest path between two points may not look
straight from the point of view of a distant observer. However, from the
point of view of the photon, it always travels straight (ie. the photon
itself always goes ahead, without never turning to any other direction).
I think that the shortest path between two points in a curved space is
called a geodetic line, or something like that.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Jan Walzer wrote:
> Wasn't there a thread 'bout a relativistic raytracer ? ...
> I'm sure someone has the link to the animations, of this
> raytracers, that does a red/blueshift when in motion ...
Yeah, maybe revise my version estimate down a few...
> you mean photons won't always fly straight, but be
> affected by the mass of objects ? I can think of
> easier ways of doing a blackhole
Easy? EASY?! Them's fightin' words!
> > YKYBRTALNTANPATLW...?
> ^ ^^^^^^^^^
"...and living next to a nuclear particle accelerator too long..."
(www.fnal.gov)
--
Tim Cook
http://empyrean.scifi-fantasy.com
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------
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"Warp" <war### [at] tagpovrayorg> schrieb im Newsbeitrag
news:3bf78f14@news.povray.org...
> Timothy R. Cook <tim### [at] scifi-fantasycom> wrote:
> : Does ANYTHING in POV have mass? heehe
>
> POV only simulates infinitely thin surfaces. Such surfaces can't have
mass.
media ....
you could also describe mass-distribution with a 3d-function..
--
Jan Walzer <jan### [at] lzernet>
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you got me ...
it wasn't written as a diplom-thesis, but as a trivial news-comment ...
I thought with some common-sense people are able to read what I meant ...
Of course there are some specialists out there ...
--
Jan Walzer <jan### [at] lzernet>
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I would say geodesic. But i'm not sure anyway.
Will
PS: i shouldn't miss any more differential geometry class.
"Warp" <war### [at] tagpovrayorg> escreveu na mensagem
news:3bf790f8@news.povray.org...
> Jan Walzer <jan### [at] lzernet> wrote:
> : you mean photons won't always fly straight, but be affected by
> : the mass of objects ?
>
> In fact, photons do always "fly" straight.
> Of course the meaning of "straight" is actually "the shortest path
between
> two points in space". In a cartesian coordinate system this is what we
usually
> think as "a straight line". However, according to the theory, space is not
> a cartesian coordinate system, but it's bent due to masses in it. In this
kind
> of curved space the real shortest path between two points may not look
> straight from the point of view of a distant observer. However, from the
> point of view of the photon, it always travels straight (ie. the photon
> itself always goes ahead, without never turning to any other direction).
> I think that the shortest path between two points in a curved space is
> called a geodetic line, or something like that.
>
> --
> #macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
> rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
> ],13),8)-3,10>#end blob{N(array[6]{11117333955,
> 7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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> Does ANYTHING in POV have mass? heehe
Rendering times on my P233 are often so long I'm positive they must
weigh something :)
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> Wasn't there a thread 'bout a relativistic raytracer ? ...
> I'm sure someone has the link to the animations, of this
> raytracers, that does a red/blueshift when in motion ...
http://www.anu.edu.au/physics/Searle/Obsolete/Raytracer.html
Very well worth a look if you haven't seen them before.
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Jan Walzer <jan### [at] lzernet> wrote:
: you got me ...
: it wasn't written as a diplom-thesis, but as a trivial news-comment ...
: I thought with some common-sense people are able to read what I meant ...
: Of course there are some specialists out there ...
I'm a hopeless perfectionist.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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On 18 Nov 2001 05:44:08 -0500, Warp wrote:
> point of view of the photon, it always travels straight (ie. the photon
> itself always goes ahead, without never turning to any other direction).
In fact, since time does not exist for photons, they couldn't turn even
if they "wanted" to.
--
#macro R(L P)sphere{L F}cylinder{L P F}#end#macro P(V)merge{R(z+a z)R(-z a-z)R(a
-z-z-z a+z)torus{1F clipped_by{plane{a 0}}}translate V}#end#macro Z(a F T)merge{
P(z+a)P(z-a)R(-z-z-x a)pigment{rgbt 1}hollow interior{media{emission T}}finish{
reflection.1}}#end Z(-x-x.2y)Z(-x-x.4x)camera{location z*-10rotate x*90}
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Andrew wrote:
> > Wasn't there a thread 'bout a relativistic raytracer ? ...
> > I'm sure someone has the link to the animations, of this
> > raytracers, that does a red/blueshift when in motion ...
>
> http://www.anu.edu.au/physics/Searle/Obsolete/Raytracer.html
>
> Very well worth a look if you haven't seen them before.
That was the obsolete site. It's newer one is at
http://www.anu.edu.au/Physics/Searle/Downloads.html
--
Jon A. Cruz
http://www.geocities.com/joncruz/action.html
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Ron Parker wrote:
> In fact, since time does not exist for photons, they
> couldn't turn even if they "wanted" to.
Why does't time exist for photons? It takes them time
to get from point A to point B, and their speed can be
measured; therefore, time exists for photons.
--
Tim Cook
http://empyrean.scifi-fantasy.com
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------
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On Sun, 18 Nov 2001 21:53:32 -0500, Timothy R. Cook wrote:
> Ron Parker wrote:
>> In fact, since time does not exist for photons, they
>> couldn't turn even if they "wanted" to.
>
> Why does't time exist for photons? It takes them time
> to get from point A to point B, and their speed can be
> measured; therefore, time exists for photons.
Except that since they're traveling at the speed of light, sorta by
definition, they don't experience the passage of time from their
frame of reference.
--
#macro R(L P)sphere{L F}cylinder{L P F}#end#macro P(V)merge{R(z+a z)R(-z a-z)R(a
-z-z-z a+z)torus{1F clipped_by{plane{a 0}}}translate V}#end#macro Z(a F T)merge{
P(z+a)P(z-a)R(-z-z-x a)pigment{rgbt 1}hollow interior{media{emission T}}finish{
reflection.1}}#end Z(-x-x.2y)Z(-x-x.4x)camera{location z*-10rotate x*90}
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Ron Parker <ron### [at] povrayorg> wrote:
: In fact, since time does not exist for photons, they couldn't turn even
: if they "wanted" to.
What happens when the photon "hits" a refractive object? Why does it "bend"
at the surface of the object? Why does it seem to go slower through the object?
I have heard this explanation that the photon is "absorbed" and another
photon (apparently a different one) is emitted. However, I have never
understood this explanation. Even in very solid matter atoms and molecules are
extremely far apart from each other, which means that there's quite a lot of
space between them; how come every and each one of the incoming photons are
absorbed and none goes through the space between the atoms without never
colliding with them? And what causes the change in direction at the surface
of the object? What causes the change in direction inside the object if the
density of the object is not constant? Why does the photon _always_ change
its path to the exact same direction? How, for example, electrons can travel
in water faster than photons can (ie. why don't electrons collide in the same
way as photons; electrons are a lot bigger)?
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Warp wrote:
> What happens when the photon "hits" a refractive object?
> Why does it "bend" at the surface of the object? Why does
> it seem to go slower through the object?
Because it DOES go slower through the object. The line is
'nothing travels faster than the speed of light *in a vaccuum*'.
If you pass the light through an object, it isn't going as
fast as in vaccuum.
(refer to
http://www.fnal.gov/pub/inquiring/questions/quesrelativity.html
for other related topics...)
> How, for example, electrons can travel in water faster
> than photons can (ie. why don't electrons collide in the
> same way as photons; electrons are a lot bigger)?
The explanation for that is: electrons don't travel, they're
pushed aside thusly:
-> -> ->e eeeeeeeeeeeeeee
*thunk*
eeeeeeeeeeeeeeee
*shove*
eeeeeeeeeeeeeeee
eeeeeeeeeeeeeee -> -> ->e
--
Tim Cook
http://empyrean.scifi-fantasy.com
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------
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> What happens when the photon "hits" a refractive object? Why does it
"bend"
> at the surface of the object? Why does it seem to go slower through
the object?
> I have heard this explanation that the photon is "absorbed" and
another
> photon (apparently a different one) is emitted. However, I have never
> understood this explanation. Even in very solid matter atoms and
molecules are
> extremely far apart from each other, which means that there's quite a
lot of
> space between them; how come every and each one of the incoming
photons are
> absorbed and none goes through the space between the atoms without
never
> colliding with them?
Though this sort of thing was never my strong point, I'll have a go...
While the spaces between the nuclei in a solid might be very large,
electrons "fill" these spaces by virtue of their exceedingly high speeds
and quantum mechanical nature. Electrons interact primarily through the
EM force here, and as a photon is the mediating particle of the EM
force, the two very readily interact. It's probably wise to recall the
wave/particle duality of light, since the wavelength of visible light is
large compared to the spacing between atoms (a few 100x larger). This
wavelength can be thought of as the "size" of the photon in this case I
think, and so combining the large "size" of photons and the ease of
interaction with electrons, you have a large "cross-section" for the
interaction. The larger the cross-section, the more likely the
reaction.
> And what causes the change in direction at the surface
> of the object? What causes the change in direction inside the object
if the
> density of the object is not constant? Why does the photon _always_
change
> its path to the exact same direction?
Good question. The answer is probably buried deep in some obscure
equation somewhere, and even then could probably get summed up as "it
just does" :) In other words, I have no idea. A related question I
guess is how exactly a mirror works.
> How, for example, electrons can travel
> in water faster than photons can (ie. why don't electrons collide in
the same
> way as photons; electrons are a lot bigger)?
IIRC electrons have a "drift velocity" of a few cm per second in a
conducting metal. This is the actual speed at which they move through
the metal when conducting electricity. However, as Tim says, they shove
each other along, and as soon as one starts moving, all of the others in
the circuit are pushed into moving.
Finally I should note that a photon NEVER travels slower than c. ALL
apparent slowing of light is due to absorption/re-emission. While this
gives rise to a "speed of light in material x", the photons themselves
are still moving at c. Other particles can and do exceed this speed,
however, giving rise to a phenomenon known as Cerenkov radiation. A
high energy particle will produce a "bow wave" when it travels faster
than the apparent speed of light in a material, visible as a cone of
light (which tends to be blue). This is the reason why the water in
cooling ponds (is that the term?) of nuclear reactors, where they leave
the spent fuel to cool off for a while, glows blue. It's the Cerenkov
radiation resulting from all the nuclear decay products whizzing through
the water.
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Timothy R. Cook <tim### [at] scifi-fantasycom> wrote:
:> Why does it seem to go slower through the object?
: Because it DOES go slower through the object.
That really didn't answer my question. Why does it go slower inside the
object?
: The line is
: 'nothing travels faster than the speed of light *in a vaccuum*'.
I know that, and I wasn't asking that.
:> How, for example, electrons can travel in water faster
:> than photons can (ie. why don't electrons collide in the
:> same way as photons; electrons are a lot bigger)?
: The explanation for that is: electrons don't travel, they're
: pushed aside thusly:
I wasn't referring to electric current. I was referring to what happens
in nuclear reactors (I think that it's called Tserenkov's phenomenon or
something similar): Electrons travel in water faster than light, which
causes a greenish glow (a kind of "sonic boom" but with light instead of
sound).
And besides, eletric current travels quite slower than c. I think that
in copper it travels at something like 0.7c.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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in news:3bf8eeef@news.povray.org Warp wrote:
> Why does it go slower inside the
> object?
>
From Maxwells third and fourth
c = 1/(E0*U0)^0.5
E0 = electric permittivity for free space
U0 = magnetic permittivity for free space
E0 = 8.85 x 10^-12 C^2 N^-1 m^-2
U0 = 4pi x 10^-7 Wb A^-1 m^-1
c = 2.999 x 10^8 m s^-1
In matter E0 and U0 become E and U
For most optical materials is nearnly equal to unity so that
n = c/v = E^0.5
From some very old notes from optics class.
Ingo
--
Photography: http://members.home.nl/ingoogni/
Pov-Ray : http://members.home.nl/seed7/
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In article <3bf8ca76@news.povray.org>, war### [at] tagpovrayorg says...
> extremely far apart from each other, which means that there's quite a lot of
> space between them; how come every and each one of the incoming photons are
> absorbed and none goes through the space between the atoms without never
> colliding with them?
You are thinking of photons as a kind of simple particle traveling along
a well-defined route from point A to point B.
But this is completely wrong when the photon is "near" some kind of
obstacle, thinking of it as a wave is a far better approximation in this
case -> since a wave can, at the same time, hit and miss ALL obstacles in
its path, it should be clear they all photons behave equally.
Lutz-Peter
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Timothy R. Cook scribis news:3BF8DB9D.E7FA7611@scifi-fantasy.com:
> Because it DOES go slower through the object. The line is
> 'nothing travels faster than the speed of light *in a vaccuum*'.
> If you pass the light through an object, it isn't going as
> fast as in vaccuum.
I had read of ceasium(sp?) gass heated to a certian high temprature that
has an IOR of less than 1. i.e. light traveles faster than the speed of
light in a vacuum. I havent seen this article disputed yet either. So maybe
it is true.
---
G^is poste,
Arto
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Having no mass, photons always travel at speed of light, even when they
go through transparent objects. They are absorbed and emitted several
times before they escape the material. The collective effect of billions
of them in a beam is as they travel slower than c. This collective
behavior is correctly described by Maxwell's equations. Individual
photons are better described by quantum mechanics. This
collective behavior is what is simulated in povray, the behavior of
beams of light
best described by Maxell's eqs.
Alberto
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> I had read of ceasium(sp?) gass heated to a certian high temprature
that
> has an IOR of less than 1. i.e. light traveles faster than the speed
of
> light in a vacuum. I havent seen this article disputed yet either. So
maybe
> it is true.
I've had a look, but there are not too many clear explanations on this
matter. It seems that the Caesium was used to create a region of
"anomalous dispersion", which means that the wavelength dependence of
the IOR is reversed. Shining a laser pulse through this caused a pulse
to be emitted from the other side of the chamber BEFORE the original
pulse had even reached it. Sounds amazing, and sounds like
faster-than-light, but apparently it isn't.
What had happened was that the group velocity of the light had been
increased above the normal speed of light. Normally, the group velocity
of light is the same as the signal velocity, ie information is
transmitted at the group velocity. However, in the case of anomalous
dispersion, the group velocity is no longer the signal velocity, and no
information is carried at this speed. The peak of the pulse travelled
at the group velocity, but energy did not.
More than this I can't tell you, I'm afraid. However, many people note
that this kind of thing is very prone to media misinterpretation, mostly
because the "speed of light" NORMALLY refers to the speed of energy
transfer, but in fact a wave has many different speeds of propagation,
depending on exactly what property of the wave you are looking at.
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> I wasn't referring to electric current. I was referring to what happens
> in nuclear reactors (I think that it's called Tserenkov's phenomenon or
> something similar): Electrons travel in water faster than light, which
> causes a greenish glow (a kind of "sonic boom" but with light instead of
> sound).
Cerenkov Radiation.
AFAIR, subatomic particles travelling faster than the speed of light in
water (or air) hit the air, come to a (relatively) screeching halt and
dump their excess energy, some of which makes it into the blue end of the
visible spectrum.
If you want more info, I'll ask my friend who works on Nuclear systems.
Bye for now,
Jamie.
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Andrew scribis news:3bf96612@news.povray.org:
> What had happened was that the group velocity of the light had been
> increased above the normal speed of light. Normally, the group velocity
> of light is the same as the signal velocity, ie information is
> transmitted at the group velocity. However, in the case of anomalous
> dispersion, the group velocity is no longer the signal velocity, and no
> information is carried at this speed. The peak of the pulse travelled
> at the group velocity, but energy did not.
>
> More than this I can't tell you, I'm afraid. However, many people note
> that this kind of thing is very prone to media misinterpretation, mostly
> because the "speed of light" NORMALLY refers to the speed of energy
> transfer, but in fact a wave has many different speeds of propagation,
> depending on exactly what property of the wave you are looking at.
That's the best explanation I have seen in a long while of what happened.
--
Gis poste, Arto.
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> That's the best explanation I have seen in a long while of what
happened.
Glad to help, but I can't really say I understand it all that well ;-)
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Alberto Mendoza <jac### [at] usbve> wrote:
: Having no mass, photons always travel at speed of light, even when they
: go through transparent objects. They are absorbed and emitted several
: times before they escape the material.
I can grasp this. However, what I still don't understand is the refraction
phenomenon.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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On 20 Nov 2001 06:38:08 -0500, Warp wrote:
> Alberto Mendoza <jac### [at] usbve> wrote:
>: Having no mass, photons always travel at speed of light, even when they
>: go through transparent objects. They are absorbed and emitted several
>: times before they escape the material.
>
> I can grasp this. However, what I still don't understand is the refraction
> phenomenon.
Understanding refraction (and diffraction, too) requires one to see the
energy as waves instead of as particles. It's impossible to understand as
long as you keep thinking of them as strictly photons.
--
#macro R(L P)sphere{L __}cylinder{L P __}#end#macro P(_1)union{R(z+_ z)R(-z _-z)
R(_-z*3_+z)torus{1__ clipped_by{plane{_ 0}}}translate z+_1}#end#macro S(_)9-(_1-
_)*(_1-_)#end#macro Z(_1 _ __)union{P(_)P(-_)R(y-z-1_)translate.1*_1-y*8pigment{
rgb<S(7)S(5)S(3)>}}#if(_1)Z(_1-__,_,__)#end#end Z(10x*-2,.2)camera{rotate x*90}
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Ron Parker <ron### [at] povrayorg> wrote:
: Understanding refraction (and diffraction, too) requires one to see the
: energy as waves instead of as particles. It's impossible to understand as
: long as you keep thinking of them as strictly photons.
In fact, I personally like to think about light as a(n electromagnetic) wave,
which just sometimes happens to act like a bunch of particles for some
weird duality phenomenon.
I know that this "photon" idea has got so strong in almost 100 years that
many people only know about photons and nothing else. They don't even
understand what is a wave. Of course this is logical: It's easier for the
human mind to grasp the concept of a tiny particle "flying" in space than
an esoteric "wave" which exists and advances in the vacuum.
I personally like to think that photons do not really exist, but they are
just a "mathematical help" to understand the behaviour of electromagnetic
waves. As many other things in quantum mechanics, there's a minimal amount
of eletromagnetic radiation which can exist, and every amount of
electromagnetic radiation is a direct multiple of this minimum amount. This
minimum amount is what we call "photon". Due to its properties it makes the
wave sometimes act like if it was made of particles.
The wave itself is just an advancing phenomenon caused by changes in the
electromagnetic field. Of course I don't claim that I fully understand this.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Cerenkov radiation (BTW; the first C should really have an inverted "^"
above it, like in unicode:010C) is caused by the fact that tachyons (FTL
particles) have an negative-imaginary total energy, and they can
actually accelerate by LOSING energy; this is given off as Cerenkov
radiation
I think this thread would make more sense if it was ROT-13'd
--
From the Grey Knight
//@---signature---
// Grey Knight's site of the week:
url{ "http://mathworld.wolfram.com" }
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On Wed, 28 Nov 2001 14:45:28 +0000, s1631001 wrote:
> Cerenkov radiation (BTW; the first C should really have an inverted "^"
> above it, like in unicode:010C) is caused by the fact that tachyons (FTL
I was right there with you right up to the point where you mentioned
tachyons, which haven't been proven to exist.
Cerenkov radiation is the shockwave from plain ol' particles that happen to
be going faster than whatever the speed of light is in the medium in which
they're traveling. Same as a sonic boom, but with light.
--
#macro R(L P)sphere{L __}cylinder{L P __}#end#macro P(_1)union{R(z+_ z)R(-z _-z)
R(_-z*3_+z)torus{1__ clipped_by{plane{_ 0}}}translate z+_1}#end#macro S(_)9-(_1-
_)*(_1-_)#end#macro Z(_1 _ __)union{P(_)P(-_)R(y-z-1_)translate.1*_1-y*8pigment{
rgb<S(7)S(5)S(3)>}}#if(_1)Z(_1-__,_,__)#end#end Z(10x*-2,.2)camera{rotate x*90}
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Ron Parker wrote:
> I was right there with you right up to the point where you mentioned
> tachyons, which haven't been proven to exist.
I was using the word tachyon to refer to a particle travelling faster
than local c. Sorry, that wasn't very nice of me...
BTW: I'm trying to put together a collection of all the news.povray.org
signatures; does anyone care?
--
From the Grey Knight
//@---signature---
contact{ email "gre### [at] yahoocom" }
// Grey Knight's site of the week:
url{ "http://mathworld.wolfram.com" }
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On Wed, 28 Nov 2001 16:05:13 +0000, s1631001 wrote:
> Ron Parker wrote:
>> I was right there with you right up to the point where you mentioned
>> tachyons, which haven't been proven to exist.
> I was using the word tachyon to refer to a particle travelling faster
> than local c. Sorry, that wasn't very nice of me...
>
> BTW: I'm trying to put together a collection of all the news.povray.org
> signatures; does anyone care?
I dunno if anyone cares, but it sounds like a fun project. I've rendered
most of them, but not kept copies. Note that I have several (I think it's
up to seven now) that run in random rotation, so you might have to look
carefully to collect the whole set.
--
#macro R(L P)sphere{L F}cylinder{L P F}#end#macro P(V)merge{R(z+a z)R(-z a-z)R(a
-z-z-z a+z)torus{1F clipped_by{plane{a 0}}}translate V}#end#macro Z(a F T)merge{
P(z+a)P(z-a)R(-z-z-x a)pigment{rgbf 1}hollow interior{media{emission 3-T}}}#end
Z(-x-x.2x)camera{location z*-10rotate x*90normal{bumps.02scale.05}}
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> I think this thread would make more sense if it was ROT-13'd
Preraxbi enqvngvba (OGJ; gur svefg P fubhyq ernyyl unir na vairegrq "^"
nobir vg, yvxr va havpbqr:010P) vf pnhfrq ol gur snpg gung gnpulbaf (SGY
cnegvpyrf) unir na artngvir-vzntvanel gbgny raretl, naq gurl pna
npghnyyl nppryrengr ol YBFVAT raretl; guvf vf tvira bss nf Preraxbi
enqvngvba
V guvax guvf guernq jbhyq znxr zber frafr vs vg jnf EBG-13'q
--
Sebz gur Terl Xavtug
//@---fvtangher---
// Terl Xavtug'f fvgr bs gur jrrx:
hey{ "uggc://zngujbeyq.jbysenz.pbz" }
--
Rick
Kitty5 WebDesign - http://Kitty5.com
POV-Ray News & Resources - http://Povray.co.uk
TEL : +44 (01270) 501101 - FAX : +44 (01270) 251105 - ICQ : 15776037
PGP Public Key
http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0x231E1CEA
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> I think this thread would make more sense if it was ROT-13'd (and
spellchecked)
Prefab enqvngvba (OGJ; guru sedge P fubsy beryl unit an verger "^"
knobbier vg, ever van havpbqr:010P) if panfry old guru smog gung gunplay
(SGY
cnegvpyrf) unit an rangier-vzntvanel bony rarely, nag girl pan
phenyl nppryrengr old YBFVAT rarely; guff if tire bass no Prefab
enqvngvba
V guava guff govern boy nor zebra far vs. vg junk EBG-13'q
--
Sobs guru Teri Ragtag
//@---fvtangher---
// Teri Xavtug'f fever bus guru jerks:
hey{ "eggs://zngujbeyq.bison.pubs" }
--
Rick
Kitty5 WebDesign - http://Kitty5.com
POV-Ray News & Resources - http://Povray.co.uk
TEL : +44 (01270) 501101 - FAX : +44 (01270) 251105 - ICQ : 15776037
PGP Public Key
http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0x231E1CEA
Post a reply to this message
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Carson radiation (BTW; the froth C shovel orderly have no irate "^"
above it, rare in Unicode:010C) vs. nasal big the fib that tracing
(FTL
particles) have no entire-imaginary opal energy, ant they can
curtly accelerate big LOSING energy; this vs. giver off abs Carson
radiation
I thing this tires owl ape moron sane if. it wax ROT-13'd
hmm - unscrambling and spellchecking the scrambled spellchecked message is
rather interesting
(sowwy)
--
Rick
Kitty5 WebDesign - http://Kitty5.com
POV-Ray News & Resources - http://Povray.co.uk
TEL : +44 (01270) 501101 - FAX : +44 (01270) 251105 - ICQ : 15776037
PGP Public Key
http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0x231E1CEA
Post a reply to this message
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s1631001 <s16### [at] namtarqubacuk> wrote:
: I was using the word tachyon to refer to a particle travelling faster
: than local c.
"Local c"? I think that's a misleading term as c is constant. Always.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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On 28 Nov 2001 15:56:31 -0500, Warp wrote...
> s1631001 <s16### [at] namtarqubacuk> wrote:
> : I was using the word tachyon to refer to a particle travelling faster
> : than local c.
>
> "Local c"? I think that's a misleading term as c is constant. Always.
Not really. Why do you think that c is usually expressed as the speed of
light in a vacuum. The whole reason refraction works is due to changes
in the speed of light in various materials.
c is *always* the fastest that anything can travel ina given medium, but
the actual numerical value in km/sec (or whatever the correwct SI units
are) varies from material to material.
Of course I could be misunderstanding what you mean.
Bye for now,
Jamie.
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Jamie Davison <jam### [at] ntlworldcom> wrote:
: Not really. Why do you think that c is usually expressed as the speed of
: light in a vacuum. The whole reason refraction works is due to changes
: in the speed of light in various materials.
c is the speed of light in vacuum. Period. It's constant. There are no
different c's for different media.
: c is *always* the fastest that anything can travel ina given medium
Nope, c is the speed of light in vacuum. Nothing else.
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Warp wrote:
>
> c is the speed of light in vacuum. Period. It's constant. There are no
> different c's for different media.
Well, this is only a matter of notation. I have had teachers
that used c0 for "your" c, and "c" for Jamie's c. I've also
had other teachers that used "c" for "your" c and "c'" for
Jamie's.
--
Adrien Beau adr### [at] freefr http://adrien.beau.free.fr/
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I seldom use this one but here goes
--
/* Nekar Xenos */#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);
blob{#while((K-N).x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(
vlength(N-K)<vlength(X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N
,1,1 scale.02}sphere{<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1
scale.01 }#end pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}
"s1631001" <s16### [at] namtarqubacuk> wrote in message
news:3C0### [at] namtarqubacuk...
> Ron Parker wrote:
> > I was right there with you right up to the point where you mentioned
> > tachyons, which haven't been proven to exist.
> I was using the word tachyon to refer to a particle travelling faster
> than local c. Sorry, that wasn't very nice of me...
>
> BTW: I'm trying to put together a collection of all the news.povray.org
> signatures; does anyone care?
>
> --
> From the Grey Knight
> file://@---signature---
> contact{ email "gre### [at] yahoocom" }
> // Grey Knight's site of the week:
> url{ "http://mathworld.wolfram.com" }
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.298 / Virus Database: 161 - Release Date: 2001/11/13
Post a reply to this message
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That is quite bizarre. Intererstingly, the encoded message is almost
pronouncable in places...
Here's my Big List of Sig's so far. If your favourite isn't on it, let
me know.
Now I just need to make my _own_ POV-Sig...
"Rick [Kitty5]" wrote:
>
> Carson radiation (BTW; the froth C shovel orderly have no irate "^"
> above it, rare in Unicode:010C) vs. nasal big the fib that tracing
> (FTL
> particles) have no entire-imaginary opal energy, ant they can
> curtly accelerate big LOSING energy; this vs. giver off abs Carson
> radiation
>
> I thing this tires owl ape moron sane if. it wax ROT-13'd
>
> hmm - unscrambling and spellchecking the scrambled spellchecked message is
> rather interesting
>
> (sowwy)
> --
>
> Rick
>
> Kitty5 WebDesign - http://Kitty5.com
> POV-Ray News & Resources - http://Povray.co.uk
> TEL : +44 (01270) 501101 - FAX : +44 (01270) 251105 - ICQ : 15776037
>
> PGP Public Key
> http://pgpkeys.mit.edu:11371/pks/lookup?op=get&search=0x231E1CEA
--
From the Grey Knight
//@---signature---
contact{ email "gre### [at] yahoocom" }
// Grey Knight's site of the week:
url{ "http://mathworld.wolfram.com" }
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Sorry, I was in a rush to get home so I just used "local c" instead of
"local speed of light" for brevity.
Warp wrote:
>
> s1631001 <s16### [at] namtarqubacuk> wrote:
> : I was using the word tachyon to refer to a particle travelling faster
> : than local c.
>
> "Local c"? I think that's a misleading term as c is constant. Always.
>
> --
> #macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
> rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
> ],13),8)-3,10>#end blob{N(array[6]{11117333955,
> 7382340,3358,3900569407,970,4254934330},0)}// - Warp -
--
From the Grey Knight
//@---signature---
contact{ email "gre### [at] yahoocom" }
// Grey Knight's site of the week:
url{ "http://mathworld.wolfram.com" }
Post a reply to this message
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s1631001 wrote:
> Here's my Big List of Sig's so far.
Ahem.
--
signature{
"Grey Knight"
contact{
email "gre### [at] yahoocom"
}
site_of_week{
url "http://mathworld.wolfram.com"
}
}
Post a reply to this message
Attachments:
Download 'us-ascii' (6 KB)
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"s1631001" <s16### [at] namtarqubacuk> wrote in message
news:3C060EE4.66F8905E@namtar.qub.ac.uk...
> That is quite bizarre. Intererstingly, the encoded message is almost
> pronouncable in places...
>
> Here's my Big List of Sig's so far. If your favourite isn't on it, let
> me know.
> Now I just need to make my _own_ POV-Sig...
>
Where? I don't see anything...
--
/* Nekar Xenos */#local N=<-20,40,100>;#local K=<20,-40,100>;#local R=seed(0);
blob{#while((K-N).x>0)#local X=N;#local N=N+<rand(R),rand(R),1>/3;#local N=(
vlength(N-K)<vlength(X-K)?N:2*X-N);sphere{<N.y,-N.x,N.z>,1,1 scale .02}sphere{N
,1,1 scale.02}sphere{<-N.x-40,N.y,N.z>1,1 scale.01}sphere{<N.x+40,-N.y,N.z>1,1
scale.01 }#end pigment{rgbt 1}interior{media{emission <2,4,5>*5}}hollow}
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.298 / Virus Database: 161 - Release Date: 2001/11/13
Post a reply to this message
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Adrien Beau <adr### [at] freefr> wrote:
: Well, this is only a matter of notation. I have had teachers
: that used c0 for "your" c, and "c" for Jamie's c. I've also
: had other teachers that used "c" for "your" c and "c'" for
: Jamie's.
c can't be anything else than the speed of light in vacuum.
The energy of an object moving at speed v is:
E = mc^2/sqrt(1-v^2/c^2)
You can easily calculate the energy of a (massive) object moving at c
and at a speed higher than c (well, the last one may not be that easy).
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Where's my sig?
--
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}// - Warp -
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Strange, since it was your sig inspired me to start this. Well, your old
one was in it, and I've just added your current one to it as well.
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp
-*/
--
signature{
"Grey Knight"
contact{ email "gre### [at] yahoocom" }
site_of_week{ url "http://mathworld.wolfram.com" }
}
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