Superluminal Quasar Jets : The Beaming "Explanation" Appears Inadequate
Chris O'Riordan
many quasar-type jets is that it is an optical illusion due to the jets
being oriented at a fairly narrow angle to our line of sight.
Some salient question marks over this are:-
As early as 1983, for the relatively few superluminal objects then
known, the jets did not seem to be in general oriented close to the
line of sight;
In 1993 Mackay et al suggested, based on Hubble Telescope observations,
that the jet of the quasar 3C273 was nearly perpendicular, rather than
nearly parallel, to the line of sight (superluminal motion of up to
~9.6c has been observed in the inner jet);
The jet of the galaxy M87 does not seem to have a narrow-enough angle
with our line of sight to explain motion of up to ~6c observed in it.
(I summed up the material at
http://uk.geocities.com/chrisori2000/superjet.htm )
Various technical tricks, such as multiple jet-beams and twisting jets,
or precessing jets, have been proposed, as ways out. Devices which
seem increasingly convoluted in more senses than one, and perhaps as
artificial as that spectrum of tricks proposed to save the "ether" at
the turn of the 19th/20th centuries.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Chris O'Riordan" <cor...@hotmail.com> wrote in message
news:1109240200.5...@z14g2000cwz.googlegroups.com...
> The conventional explanantion for the superluminal motions observed in
> many quasar-type jets is that it is an optical illusion due to the jets
> being oriented at a fairly narrow angle to our line of sight.
...
If the jets are truly superlumenal, how is it that we can see light from
them? Since we *do* see light from them, and their spectra are
"reasonable", the rest is "tricks of geometry". If they were superlumenal,
the light could never leave...
David A. Smith
Sam Wormley
> The conventional explanantion for the superluminal motions observed in
> many quasar-type jets is that it is an optical illusion due to the jets
> being oriented at a fairly narrow angle to our line of sight.
>
http://www.mhhe.com/physsci/astronomy/fix/student/chapter24/24f09.html
http://www.mhhe.com/physsci/astronomy/fix/student/chapter24/24f10.html
christie.jones
message news:kPkTd.81133$Yu.56373@fed1read01...
Why? If the velocity of light isn't source dependent then what does the
sources velocity have to do with the amount of time it takes for the light
to reach us? BTW I am just asking a question. I'm not saying the source is
going >c.
---
Thomas
"The idea of God is the sole wrong for which I cannot forgive mankind."
--Le Marquis de Sade
christie.jones
news:flmTd.994$r55.269@attbi_s52...
Nevermind. For some reason I skipped the part about the spectra being
"reasonable". I understand now.
Thomas
Jonathan Silverlight
(dlzc)" <N@?.D.invalid> writes
We could see Cerenkov radiation (it's been looked for in searches for
tachyons) but presumably the spectrum from a jet doesn't match what's
expected for Cerenkov radiation, so that's not the answer.
--
Support the DEC Tsunami Appeal http://www.dec.org.uk/.
Remove spam and invalid from address to reply.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Jonathan Silverlight" <jsilve...@spam.merseia.fsnet.co.uk.invalid>
wrote in message news:Y2GSMuv$NjHC...@merseia.fsnet.co.uk...
> In message <kPkTd.81133$Yu.56373@fed1read01>, "N:dlzc D:aol T:com (dlzc)"
> <N@?.D.invalid> writes
>>Dear Chris O'Riordan:
>>
>>"Chris O'Riordan" <cor...@hotmail.com> wrote in message
>>news:1109240200.5...@z14g2000cwz.googlegroups.com...
>>> The conventional explanantion for the superluminal motions observed in
>>> many quasar-type jets is that it is an optical illusion due to the jets
>>> being oriented at a fairly narrow angle to our line of sight.
>>...
>>
>>If the jets are truly superlumenal, how is it that we can see light from
>>them? Since we *do* see light from them, and their spectra are
>>"reasonable", the rest is "tricks of geometry". If they were
>>superlumenal,
>>the light could never leave...
>
> We could see Cerenkov radiation (it's been looked for in searches for
> tachyons) but presumably the spectrum from a jet doesn't match what's
> expected for Cerenkov radiation, so that's not the answer.
My point was, if they are moving towards us in any sense, faster than c,
then the particle/body/object will outrun the light. We could *see*
nothing coming towards us. And the faster it is, the closer it would have
to be to "motion at 90 deg to line of sight" to keep from outrunning light
that leaves towards us.
I agree, Cerenkov radiation places limits on ions, and even on sources of
thermally-based light emission (which liberates charges).
David A. Smith
Luigi Caselli
news:1109240200.5...@z14g2000cwz.googlegroups.com...
> The conventional explanantion for the superluminal motions observed in
> many quasar-type jets is that it is an optical illusion due to the jets
> being oriented at a fairly narrow angle to our line of sight.
>
> Some salient question marks over this are:-
>
> As early as 1983, for the relatively few superluminal objects then
> known, the jets did not seem to be in general oriented close to the
> line of sight;
>
> In 1993 Mackay et al suggested, based on Hubble Telescope observations,
> that the jet of the quasar 3C273 was nearly perpendicular, rather than
> nearly parallel, to the line of sight (superluminal motion of up to
> ~9.6c has been observed in the inner jet);
>
> The jet of the galaxy M87 does not seem to have a narrow-enough angle
> with our line of sight to explain motion of up to ~6c observed in it.
According to Einstein, nothing can be faster than light speed inside our
universe...
So superluminal motions must be only optical illusion...
Otherwise you must create a new theory and throw away relativity.
Luigi Caselli
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Luigi Caselli" <luigic...@anyspamrefusediol.it> wrote in message
news:KjsTd.49915$QG6.8...@twister2.libero.it...
... which some consider desirable.
But they must also throw away Maxwell, since he allows light to leave these
"superlumenal" event.
David A. Smith
Martin Brown
> Dear Chris O'Riordan:
>
> "Chris O'Riordan" <cor...@hotmail.com> wrote in message
> news:1109240200.5...@z14g2000cwz.googlegroups.com...
>
>>The conventional explanantion for the superluminal motions observed in
>>many quasar-type jets is that it is an optical illusion due to the jets
>>being oriented at a fairly narrow angle to our line of sight.
>
And it is a very good explanation that fits the observations nicely.
> ...
>
> If the jets are truly superlumenal, how is it that we can see light from
> them? Since we *do* see light from them, and their spectra are
> "reasonable", the rest is "tricks of geometry". If they were superlumenal,
> the light could never leave...
Not quite. Provided that the beam is pointing roughly towards us and/or
not receding faster than the speed of light we can still see it easily.
If a truly superluminal jet were pointed at us the material in the jet
would arrive marginally before the light emitted from it (assuming that
it continued to emit light and stayed superluminal all the way).
But even if it were truly receding faster than the speed of light we
would still see the turbulent backwash it created in the intergalactic
medium. The high resolution 5GHz image of the radio galaxy Cygnus A
shows one relativistic jet very clearly most of the way out into the lobe.
But by far the simplest explanation of apparent superluminal motion in
quasar jets is that it is a purely geometrical line of sight effect of
beaming with standard relativistic physics.
Regards,
Martin Brown
Luigi Caselli
messaggio news:QosTd.81173$Yu.50458@fed1read01...
> Dear Luigi Caselli:
>
> "Luigi Caselli" <luigic...@anyspamrefusediol.it> wrote in message
> news:KjsTd.49915$QG6.8...@twister2.libero.it...
> >
> > universe...
> > So superluminal motions must be only optical illusion...
> > Otherwise you must create a new theory and throw away relativity.
>
> ... which some consider desirable.
Yes, for example Star Trek fans hate this kind of silly speed limit...
> But they must also throw away Maxwell, since he allows light to leave
these
> "superlumenal" event.
Too many things to throw away...
Luigi Caselli
DavidBowman
good, concise article from astrophysical journal. It includes
fascinating pix of the "superluminal" features over time, too:
http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v520n2/39787/39787.html
=[ d
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Martin Brown" <|||newspam|||@nezumi.demon.co.uk> wrote in message
news:cvlkkp$2th$1...@news7.svr.pol.co.uk...
> N:dlzc D:aol T:com (dlzc) wrote:
...
>>>The conventional explanantion for the superluminal motions observed in
>>>many quasar-type jets is that it is an optical illusion due to the jets
>>>being oriented at a fairly narrow angle to our line of sight.
>>
> And it is a very good explanation that fits the observations nicely.
>> ...
>>
>> If the jets are truly superlumenal, how is it that we can see light from
>> them? Since we *do* see light from them, and their spectra are
>> "reasonable", the rest is "tricks of geometry". If they were
>> superlumenal, the light could never leave...
>
> Not quite. Provided that the beam is pointing roughly towards us and/or
> not receding faster than the speed of light we can still see it easily.
> If a truly superluminal jet were pointed at us the material in the jet
> would arrive marginally before
We are going to pick nits here, I guess. At 6c, without "Cerenkov braking"
(my apologies to purists), "marginally before" would be 5000 years before,
for a 6000 year trip at c.
Classical Cerenkov radiation involves a medium and a moving charge.
Uncharged matter would theoretically not be subject to Cerenkov radiation
(I don't know if neutron streams are faster than c/1.4, but it would be
hard to separate them from the other particles in the mix that *are*
charged).
> the light emitted from it (assuming that it continued to emit light and
> stayed superluminal all the way).
And the intensity and spectrum received would be... blueshifted beyond
what? Gamma, cosmic, what? Light could not leave the surface of the face
coming at us, if it were superlumenal. 1/2 wavelength out, and the
emitting object "crashes" into the photon stream.
> But even if it were truly receding faster than the speed of light we
> would still see the turbulent backwash it created in the intergalactic
> medium. The high resolution 5GHz image of the radio galaxy Cygnus A shows
> one relativistic jet very clearly most of the way out into the lobe.
>
> But by far the simplest explanation of apparent superluminal motion in
> quasar jets is that it is a purely geometrical line of sight effect of
> beaming with standard relativistic physics.
Absolutely correct.
David A. Smith
Sam Wormley
Thanks David.
-Sam
Chris O'Riordan
N:dlzc D:aol T:com (dlzc) wrote:
I had in mind a VSL (variable light speed) possible explanation, where
the jet knots would not exceed the *local* value of c. The latter
would need to be ~3 X 10^9 m/s at least in the case of quasar 3C273,
for example.
This is just a speculation, of course. I don't know why c would
increase significantly outward along the axis of a (rotating,
supermassive) black hole. Something to do with twizzled-up spacetime,
mayhap?!
Chris O'Riordan
> N:dlzc D:aol T:com (dlzc) wrote:
>
> > Dear Chris O'Riordan:
> >
> > "Chris O'Riordan" <cor...@hotmail.com> wrote in message
> > news:1109240200.5...@z14g2000cwz.googlegroups.com...
> >
> >>The conventional explanantion for the superluminal motions observed
in
> >>many quasar-type jets is that it is an optical illusion due to the
jets
> >>being oriented at a fairly narrow angle to our line of sight.
> >
> And it is a very good explanation that fits the observations nicely.
There are key cases where it emphatically DOESN'T appear to fit, as I
mentioned in
http://www.geocities.com/chrisori2000/superjet.htm
To recap:-
(For the 7 known superluminals in 1983,) the structures did NOT in
general appear to be oriented close to the line-of-sight;
Mackay, Thompson et al suggested in 1993 that the (outer) jet of quasar
3C273 was nearly PERPENDICULAR, rather than nearly parallel, to the
line-of-sight. Superluminal motion of up to ~9.6c has been observed
along the (inner) jet;
The jet of the galaxy M87 needs to be at ~19 degrees to the
line-of-sight to explain by beaming superluminal motion of up to ~6c in
it -- but independent evidence on the jet's orientation suggests it is
at ~43 degrees to our line-of-sight.
Joseph Lazio
NDT> My point was, if they are moving towards us in any sense, faster
NDT> than c, then the particle/body/object will outrun the light. We
NDT> could *see* nothing coming towards us. And the faster it is,
NDT> the closer it would have to be to "motion at 90 deg to line of
NDT> sight" to keep from outrunning light that leaves towards us.
Yes, but the model isn't that the ejecta is moving faster than the
speed of light. Consider ejecta moving at 0.999c and moving toward
you.
--
Lt. Lazio, HTML police | e-mail: jla...@patriot.net
No means no, stop rape. | http://patriot.net/%7Ejlazio/
sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html
Joseph Lazio
CO> There are key cases where it emphatically DOESN'T appear to fit,
CO> as I mentioned in
CO> http://www.geocities.com/chrisori2000/superjet.htm
There appears to be some link rot here.
CO> To recap:-
CO> (For the 7 known superluminals in 1983,) the structures did NOT in
CO> general appear to be oriented close to the line-of-sight;
CO> Mackay, Thompson et al suggested in 1993 that the (outer) jet of
CO> quasar 3C273 was nearly PERPENDICULAR, rather than nearly
CO> parallel, to the line-of-sight. Superluminal motion of up to
CO> ~9.6c has been observed along the (inner) jet;
I can find no paper in ADS with the authors "Mackay" and "Thompson."
Perhaps you could post a reference?
CO> The jet of the galaxy M87 needs to be at ~19 degrees to the
CO> line-of-sight to explain by beaming superluminal motion of up to
CO> ~6c in it -- but independent evidence on the jet's orientation
CO> suggests it is at ~43 degrees to our line-of-sight.
Doesn't this require independent knowledge of the speed of the ejecta?
Reference?
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Joseph Lazio" <jla...@adams.patriot.net> wrote in message
news:llbra7m...@adams.patriot.net...
>>>>>> "NDT" == N:dlzc D:aol T:com \(dlzc\) <N> writes:
>
> NDT> My point was, if they are moving towards us in any sense, faster
> NDT> than c, then the particle/body/object will outrun the light. We
> NDT> could *see* nothing coming towards us. And the faster it is,
> NDT> the closer it would have to be to "motion at 90 deg to line of
> NDT> sight" to keep from outrunning light that leaves towards us.
>
> Yes, but the model isn't that the ejecta is moving faster than the
> speed of light. Consider ejecta moving at 0.999c and moving toward
> you.
The concern appears to be "what if they are superlumenal". The standard
model doesn't have the problem I described. He has so far ignored the
"normal spectrum", which also limits the jet to sublumenal speed.
Maxwell provides the conundrum I describe, since light travels at c for all
observers, yet light leaves "forward" from an object travelling at c. He
seems to be running towards Fizeau next...
David A. Smith
jgr...@seol.net.au
Then wasn't Maxwell saying c'=c+v , and thus in direct conflict with
AE?
How is the increasing length per time (velocity) of these jets
measured?
SR believers might claim that the only legitimate measurement would be
that of a traveller on the jet! Otherwise, SR is decapitated right
here, with the obvious and trivial observation that velocity has NOT
shrunken the moving body!
Jim G
c'=c+v
Jonathan Silverlight
<jla...@adams.patriot.net> writes
>>>>>> "CO" == Chris O'Riordan <cor...@hotmail.com> writes:
>
>CO> There are key cases where it emphatically DOESN'T appear to fit,
>CO> as I mentioned in
>CO> http://www.geocities.com/chrisori2000/superjet.htm
>
>There appears to be some link rot here.
>
>CO> To recap:-
>
>CO> (For the 7 known superluminals in 1983,) the structures did NOT in
>CO> general appear to be oriented close to the line-of-sight;
>
>CO> Mackay, Thompson et al suggested in 1993 that the (outer) jet of
>CO> quasar 3C273 was nearly PERPENDICULAR, rather than nearly
>CO> parallel, to the line-of-sight. Superluminal motion of up to
>CO> ~9.6c has been observed along the (inner) jet;
>
>I can find no paper in ADS with the authors "Mackay" and "Thompson."
>Perhaps you could post a reference?
There's a paper in Nature 9 September 1993, vol 365 no 6442
"Internal structure and polarisation of the optical jet of the quasar
3C273" RC Thomson CD MacKay and AE Wright, but I don't have access
online.
George Dishman
<jgr...@seol.net.au> wrote in message
news:1109461004.9...@f14g2000cwb.googlegroups.com...
>
> N:dlzc D:aol T:com (dlzc) wrote:
>>
>> Maxwell provides the conundrum I describe, since light travels at c for
>> all
>> observers, yet light leaves "forward" from an object travelling at c. He
>> seems to be running towards Fizeau next...
>
> Then wasn't Maxwell saying c'=c+v
David said "light travels at c for all observers"
hence c'=c.
http://www.fnal.gov/pub/inquiring/more/light/light_page9.html
> , and thus in direct conflict with AE?
See section 6 of Einstein's original paper:
http://www.fnal.gov/pub/inquiring/more/light/light_page9.html
> How is the increasing length per time (velocity) of these jets measured?
Length isn't too meaningful as the jets are a
continuous flow so there is no clear end to the
jet. Measuring the speed depends on non-uniformity
in the flow by following the progress of 'knots'
of matter. For example:
http://www.stsci.edu/ftp/science/m87/m87.html
and in particular this set of frames:
http://www.stsci.edu/ftp/science/m87/bw3.gif
Or look at the attached radio map here:
http://www.phy.duke.edu/~kolena/superluminalmotion.html
You might also practice your maths by trying
to answer the questions on that page ;-)
> SR believers might claim that the only legitimate measurement would be
> that of a traveller on the jet!
SR provides a set of rules for converting
measurements in one frame into another frame.
Both measurements are "legitimate" in their
respective frames.
> Otherwise, SR is decapitated right
> here, with the obvious and trivial observation that velocity has NOT
> shrunken the moving body!
It has. Someone riding on the jet would measure
a greater distance between the same knots than
an observer at rest wrt the source and viewing
the jet perpendicular to its motion.
George
jgr...@seol.net.au
George Dishman wrote:
> <jgr...@seol.net.au> wrote in message
> news:1109461004.9...@f14g2000cwb.googlegroups.com...
> >
> > N:dlzc D:aol T:com (dlzc) wrote:
> >>
> >> Maxwell provides the conundrum I describe, since light travels at
c for
> >> all
> >> observers, yet light leaves "forward" from an object travelling at
c. He
> >> seems to be running towards Fizeau next...
> >
> > Then wasn't Maxwell saying c'=c+v
>
> David said "light travels at c for all observers"
> hence c'=c.
If c'=c for ALL observers, does not l'=l for those SAME observers?
>
> http://www.fnal.gov/pub/inquiring/more/light/light_page9.html
>
> > , and thus in direct conflict with AE?
>
> See section 6 of Einstein's original paper:
>
> http://www.fnal.gov/pub/inquiring/more/light/light_page9.html
>
> > How is the increasing length per time (velocity) of these jets
measured?
>
> Length isn't too meaningful as the jets are a
> continuous flow so there is no clear end to the
> jet. Measuring the speed depends on non-uniformity
> in the flow by following the progress of 'knots'
> of matter. For example:
The view is of a train coming out of a tunnel; select a carriage (=
knot)
and measure to engine. Length is carriage -> engine velocity is
carriage
-> tunnel mouth / time
>
> http://www.stsci.edu/ftp/science/m87/m87.html
>
> and in particular this set of frames:
>
> http://www.stsci.edu/ftp/science/m87/bw3.gif
>
> Or look at the attached radio map here:
>
> http://www.phy.duke.edu/~kolena/superluminalmotion.html
>
> You might also practice your maths by trying
> to answer the questions on that page ;-)
>
> > SR believers might claim that the only legitimate measurement would
be
> > that of a traveller on the jet!
>
> SR provides a set of rules for converting
> measurements in one frame into another frame.
> Both measurements are "legitimate" in their
> respective frames.
If we applied SR to the observed velocity length which we are seeing,
then the jet would vanish! (Travelling at c it reduces to nil)
We can see the speed of the jet by way of the increasing angle between
the source and the "top", if we have a fair idea of the distance from
here.
The passenger on the jet has NO angle to observe, and so he continues
to be mistaken in his belief that he is closer to the top than he
measures. :-)
>
> > Otherwise, SR is decapitated right
> > here, with the obvious and trivial observation that velocity has
NOT
> > shrunken the moving body!
>
> It has. Someone riding on the jet would measure
> a greater distance between the same knots than
> an observer at rest wrt the source and viewing
> the jet perpendicular to its motion.
similar to above
Cheers
Jim G
c'=c+v
Sam Wormley
George Dishman
<jgr...@seol.net.au> wrote in message
news:1109545483....@l41g2000cwc.googlegroups.com...
>
> George Dishman wrote:
>> <jgr...@seol.net.au> wrote in message
>> news:1109461004.9...@f14g2000cwb.googlegroups.com...
>> >
>>
>> David said "light travels at c for all observers"
>> hence c'=c.
>
> If c'=c for ALL observers, does not l'=l for those SAME observers?
You know better than that Jim. Remember our email
discussions
IF
speed = c
THEN
....
ENDIF
>> http://www.fnal.gov/pub/inquiring/more/light/light_page9.html
>>
>> > , and thus in direct conflict with AE?
>>
>> See section 6 of Einstein's original paper:
>>
>> http://www.fnal.gov/pub/inquiring/more/light/light_page9.html
>>
>> > How is the increasing length per time (velocity) of these
>> > jets measured?
>>
>> Length isn't too meaningful as the jets are a
>> continuous flow so there is no clear end to the
>> jet. Measuring the speed depends on non-uniformity
>> in the flow by following the progress of 'knots'
>> of matter. For example:
>
> The view is of a train coming out of a tunnel; select a
> carriage (= knot) and measure to engine. Length is
> carriage -> engine velocity is carriage -> tunnel
> mouth / time
The engine passed long ago and is now out of sight
but you can choose any two carriages to get the
same effect.
>> http://www.stsci.edu/ftp/science/m87/m87.html
>>
>> and in particular this set of frames:
>>
>> http://www.stsci.edu/ftp/science/m87/bw3.gif
>>
>> Or look at the attached radio map here:
>>
>> http://www.phy.duke.edu/~kolena/superluminalmotion.html
>>
>> You might also practice your maths by trying
>> to answer the questions on that page ;-)
>>
>> > SR believers might claim that the only legitimate measurement
>> > would be that of a traveller on the jet!
>>
>> SR provides a set of rules for converting
>> measurements in one frame into another frame.
>> Both measurements are "legitimate" in their
>> respective frames.
>
> If we applied SR to the observed velocity length which we are seeing,
> then the jet would vanish! (Travelling at c it reduces to nil)
The jet is travelling at less than c, and what
we see is the reduced length, if measured on the
jet it would be longer.
> We can see the speed of the jet by way of the increasing angle between
> the source and the "top", if we have a fair idea of the distance from
> here.
> The passenger on the jet has NO angle to observe, and so he continues
> to be mistaken in his belief that he is closer to the top than he
> measures. :-)
>>
>> > Otherwise, SR is decapitated right
>> > here, with the obvious and trivial observation that velocity has NOT
>> > shrunken the moving body!
>>
>> It has. Someone riding on the jet would measure
>> a greater distance between the same knots than
>> an observer at rest wrt the source and viewing
>> the jet perpendicular to its motion.
>
> similar to above
Similar but the other way round.
George
Chris O'Riordan
http://uk.geocities.com/chrisori2000/superjet.htm , which has links to
*some* of the references.
As Jonathan Silverlight below remarks, the Nature article by Thompson,
Mackay and Wright isn't online. It appeared in 1993, and Nature hasn't
got round to putting these online yet. But, basically, the authors say
that the (outer) jet appears to be nearly parallel to the line of sight
because of the way it apparently intersects the surface of a gaseous
halo around the quasar. (Brightening of the jet coincides with
apparent edge-brightening of the halo.)
Martin Brown
>>>>>>"CO" == Chris O'Riordan <cor...@hotmail.com> writes:
>
>
> CO> There are key cases where it emphatically DOESN'T appear to fit,
> CO> as I mentioned in
> CO> http://www.geocities.com/chrisori2000/superjet.htm
>
> There appears to be some link rot here.
>
> CO> To recap:-
>
> CO> (For the 7 known superluminals in 1983,) the structures did NOT in
> CO> general appear to be oriented close to the line-of-sight;
>
> CO> Mackay, Thompson et al suggested in 1993 that the (outer) jet of
> CO> quasar 3C273 was nearly PERPENDICULAR, rather than nearly
> CO> parallel, to the line-of-sight. Superluminal motion of up to
> CO> ~9.6c has been observed along the (inner) jet;
>
> I can find no paper in ADS with the authors "Mackay" and "Thompson."
> Perhaps you could post a reference?
All the ADS links I can find for 3c273 since 1995 say that the
observations are entirely consistent with a precessing relativistic jet.
There are oblique references to the discrepancy between what is seen in
VLBI at near the core out way out in the optical. eg.
>
> CO> The jet of the galaxy M87 needs to be at ~19 degrees to the
> CO> line-of-sight to explain by beaming superluminal motion of up to
> CO> ~6c in it -- but independent evidence on the jet's orientation
> CO> suggests it is at ~43 degrees to our line-of-sight.
>
> Doesn't this require independent knowledge of the speed of the ejecta?
> Reference?
Again the modellers seem to have things under control. eg
http://searcht.netscape.com/ns/boomframe.jsp?query=%2BADS+%2Babstracts&page=1&offset=0&result_url=redir%3Fsrc%3Dwebsearch%26requestId%3D6b5238c53e22f25e%26clickedItemRank%3D1%26userQuery%3D%252BADS%2B%252Babstracts%26clickedItemURN%3Dhttp%253A%252F%252Fadsabs.harvard.edu%252Fabstract_service.html%26invocationType%3D-%26fromPage%3DNSCPToolbarNS%26amp%3BampTest%3D1&remove_url=http%3A%2F%2Fadsabs.harvard.edu%2Fabstract_service.html
And being close to us it is well studied at high resolution eg
http://searcht.netscape.com/ns/boomframe.jsp?query=%2BADS+%2Babstracts&page=1&offset=0&result_url=redir%3Fsrc%3Dwebsearch%26requestId%3D6b5238c53e22f25e%26clickedItemRank%3D1%26userQuery%3D%252BADS%2B%252Babstracts%26clickedItemURN%3Dhttp%253A%252F%252Fadsabs.harvard.edu%252Fabstract_service.html%26invocationType%3D-%26fromPage%3DNSCPToolbarNS%26amp%3BampTest%3D1&remove_url=http%3A%2F%2Fadsabs.harvard.edu%2Fabstract_service.html
Regards,
Martin Brown
Bjoern Feuerbacher
[snip]
> If c'=c for ALL observers, does not l'=l for those SAME observers?
If you mean "length" here, then no. Why should it?
[snip]
Bye,
Bjoern
Bjoern Feuerbacher
[snip]
> Then wasn't Maxwell saying c'=c+v ,
No, he indeed was not saying that.
Why do you think he was?
[snip]
Bye,
Bjoern
Jonathan Silverlight
<http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993Natur.365..1
33T&db_key=AST>, but having read the paper I'm not entirely
convinced by their argument.
For instance, has anyone confirmed the existence of this shell, whose
radius coincides with knot A1 in the jet? They say
"If this interpretation is correct and the shell feature is real and
edge-brightened, then the jet in 3C273 cannot be aligned nearly parallel
to the line of sight; it must be viewed in the plane of the sky nearly
perpendicular to the line of sight. This follows from the observed
coincidence of knot A1 with the (possibly) edge-brightened shell, which
would then be a remarkable coincidence if the jet were actually aligned
nearly parallel to the line of sight.
Consequently, the optical jet could not be beamed towards us and must be
one-sided".
That sounds a bit circular, and if we aren't seeing a shell, or not
seeing edge-brightening, the coincidence disappears.
And you still have to explain the one sided jet.
jgr...@seol.net.au
If the "transverse doppler effect" is as claimed, then the material
being emitted is giving us a false wave signature (eg fast moving H
would exhibit a wavelength other than 21cm). The composition of the jet
would need to be reappraised.
(But don't bother- Transverse Doppler was just invented to prop SR)
Jim G
c'=c+v
Greg Hennessy
<jgr...@seol.net.au> wrote:
> If the "transverse doppler effect" is as claimed, then the material
> being emitted is giving us a false wave signature (eg fast moving H
> would exhibit a wavelength other than 21cm). The composition of the jet
> would need to be reappraised.
Why are you assuming that the observed jet is of 21 cm radiation?
Jonathan Silverlight
jgr...@seol.net.au writes
>
>
>If the "transverse doppler effect" is as claimed, then the material
>being emitted is giving us a false wave signature (eg fast moving H
>would exhibit a wavelength other than 21cm). The composition of the jet
>would need to be reappraised.
>(But don't bother- Transverse Doppler was just invented to prop SR)
I don't see the relevance of this to anything that has gone before in
this thread.
No-one's talking about spectral or composition information - the
argument is about geometry and proper motion. And much of it is from
optical observation.
But are there any spectra of the jet showing lines - optical or radio?
Martin Brown
I'm not sure but I don't think any spectral lines have been seen in the
jets. The polarisation suggests it is mostly synchrotron emission.
Closest matches I could find are:
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2005A%26A...431..477J&db_key=AST&high=40c7ffefc507870
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2004A%26A...419...25F&db_key=AST&high=40c7ffefc507870
Regards,
Martin Brown
Joseph Lazio
j> The view is of a train coming out of a tunnel; select a carriage (=
j> knot) and measure to engine. Length is carriage -> engine velocity
j> is carriage tunnel mouth / time
O.k., suppose you make this measurement. Say you get 2
milliarcseconds. Suppose you also know the distance to the quasar, so
that you can convert the angular distance (in milliarcseconds) to a
linear distance (in parsecs).
Now what? You have one measurement. We don't know the velocity of
the material in the jet (other than it is probably close to c), and
you cannot necessarily use the motion of the knots, because they might
be shock waves within the jets and not reflecting the actual motion of
the material in the jet.
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Joseph Lazio" <jla...@adams.patriot.net> wrote in message
news:ll8y55o...@adams.patriot.net...
>>>>>> "j" == jgreen <jgr...@seol.net.au> writes:
>
> j> The view is of a train coming out of a tunnel; select a
> carriage (=
> j> knot) and measure to engine. Length is carriage -> engine
> velocity
> j> is carriage tunnel mouth / time
>
> O.k., suppose you make this measurement. Say you get 2
> milliarcseconds. Suppose you also know the distance to the
> quasar, so
> that you can convert the angular distance (in milliarcseconds)
> to a
> linear distance (in parsecs).
>
> Now what? You have one measurement. We don't know the
> velocity of
> the material in the jet (other than it is probably close to c),
> and
> you cannot necessarily use the motion of the knots, because
> they might
> be shock waves within the jets and not reflecting the actual
> motion of
> the material in the jet.
A shock wave *would be* the momentary motion of the material of
the jet. Not saying it is bulk jet velocity, but the knot, *if
it is pressure driven*, is motion of the material at some point.
Now if it is simply excitation due to some EM pulse... exciting a
plasma...
And if it is simply superlumenal scissors...
David A. Smith
jgr...@seol.net.au
I suppose I should apologise for taking a cheap shot at SR in this
thread- just couldn't resist :-)
OTH, if the thread is discussing material v >>c, surely the composition
of that material is relevent? And that is determined by spectra, which
I am
suggesting would be very flawed data, were transverse doppler effects
as posited.
So your question leads in an interesting direction.
Jim G
c'=c+v
jgr...@seol.net.au
Joseph Lazio wrote:
> >>>>> "j" == jgreen <jgr...@seol.net.au> writes:
>
> j> The view is of a train coming out of a tunnel; select a carriage
(=
> j> knot) and measure to engine. Length is carriage -> engine velocity
> j> is carriage tunnel mouth / time
>
> O.k., suppose you make this measurement. Say you get 2
> milliarcseconds. Suppose you also know the distance to the quasar,
so
> that you can convert the angular distance (in milliarcseconds) to a
> linear distance (in parsecs).
>
> Now what? You have one measurement. We don't know the velocity of
> the material in the jet (other than it is probably close to c), and
> you cannot necessarily use the motion of the knots, because they
might
> be shock waves within the jets and not reflecting the actual motion
of
> the material in the jet.
At a later time, see how much the angle has increased. Trig will
calculate the velocity of the "top" as it has moved per time ref its
origin.
Jim G
c'=c+v
Martin Brown
Not at all. The shock wave represents a position in the plasma where
there is a sudden change in flow speed and hence of pressure. This might
be due to a reflected density pulse going back down the beam from an
encounter further up with denser material.
A pretty good analogue for understanding shock waves is to watch how
traffic bunches on a busy motorway or turnpike when someone makes a
mistake, hits the breaks and all their tailgaters do the same. Traffic
may slow from 80mph to 60mph abruptly. And the shockwave pulse then
usually runs backwards against the flow of the traffic whilst a gap
opens up ahead of the instigators of the instability. The speed of the
knot tells you little or nothing about the bulk traffic speed.
There is also the possibility that the bright knots represent only the
position where the relativistic beam impinges upon denser gas/dust. In
this scenario nothing physical is moving faster than c even though the
point where the beam lights up the IGM can be. Precessing beams are a
distinct possibility and hints have been seen in some objects. eg
http://www.mpa-garching.mpg.de/HIGHLIGHT/2001/highlight0101_e.html
http://www.bu.edu/blazars/3c120.html
Regards,
Martin Brown
dlzc1 D:cox T:net@nospam.com N:dlzc D:aol T:com (dlzc)
"Martin Brown" <|||newspam|||@nezumi.demon.co.uk> wrote in
message news:d06jmf$kqs$1...@newsg3.svr.pol.co.uk...
> N:dlzc D:aol T:com (dlzc) wrote:
>> Dear Joseph Lazio:
>>
>> "Joseph Lazio" <jla...@adams.patriot.net> wrote in message
>> news:ll8y55o...@adams.patriot.net...
>>
>>>>>>>>"j" == jgreen <jgr...@seol.net.au> writes:
>>>
>>>j> The view is of a train coming out of a tunnel; select
>>>j> a carriage (= knot) and measure to engine. Length
>>>j> is carriage -> engine velocity is carriage tunnel
>>>j> mouth / time
I see a lot of problems with this. Communications based on a
plasma-version of a traffic jam, occurs at light speed (seeing
the brake lights). Communications based on pressure requires the
plasma to travel as fast as the knot, *at the knot*, and its
speed of sound to be altered to match the necessary velocity.
And the speed of the knot is less than the speed of traffic.
Physical alterations of the plasma stream will be speed-limited
to c or less. Granted Fizeau might extend this some (but probably
not).
> There is also the possibility that the bright knots represent
> only the position where the relativistic beam impinges upon
> denser gas/dust. In this scenario nothing physical is moving
> faster than c even though the point where the beam lights up
> the IGM can be. Precessing beams are a distinct possibility and
> hints have been seen in some objects. eg
>
> http://www.mpa-garching.mpg.de/HIGHLIGHT/2001/highlight0101_e.html
> http://www.bu.edu/blazars/3c120.html
I think this is superior. Superlumenal scissors, or the
incidence of two streams of matter, can be made to appear FTL.
David A. Smith
George Dishman
<jgr...@seol.net.au> wrote in message
news:1109826374....@l41g2000cwc.googlegroups.com...
>
> Jonathan Silverlight wrote:
>> In message <1109733419....@o13g2000cwo.googlegroups.com>,
>> jgr...@seol.net.au writes
>> >
>> >
>> >If the "transverse doppler effect" is as claimed, then the material
>> >being emitted is giving us a false wave signature (eg fast moving H
>> >would exhibit a wavelength other than 21cm). The composition of the
> jet
>> >would need to be reappraised.
>> >(But don't bother- Transverse Doppler was just invented to prop SR)
>>
>> I don't see the relevance of this to anything that has gone before in
>
>> this thread.
>> No-one's talking about spectral or composition information - the
>> argument is about geometry and proper motion. And much of it is from
>> optical observation.
>> But are there any spectra of the jet showing lines - optical or
> radio?
>
> I suppose I should apologise for taking a cheap shot at SR in this
> thread- just couldn't resist :-)
[Note: must try harder]
> OTH, if the thread is discussing material v >>c, surely the composition
> of that material is relevent? And that is determined by spectra, which
> I am
> suggesting would be very flawed data, were transverse doppler effects
> as posited.
> So your question leads in an interesting direction.
In your other reply you said:
<jgr...@seol.net.au> wrote in message
news:1109826598.8...@z14g2000cwz.googlegroups.com...
>
> Joseph Lazio wrote:
>>
>> O.k., suppose you make this measurement. Say you get 2
>> milliarcseconds. Suppose you also know the distance to the quasar, so
>> that you can convert the angular distance (in milliarcseconds) to a
>> linear distance (in parsecs).
>>
>> Now what? You have one measurement. We don't know the velocity of
>> the material in the jet (other than it is probably close to c), and
>> you cannot necessarily use the motion of the knots, because they might
>> be shock waves within the jets and not reflecting the actual motion of
>> the material in the jet.
>
> At a later time, see how much the angle has increased. Trig will
> calculate the velocity of the "top" as it has moved per time ref its
> origin.
That is the method used.
Jonathan asked "But are there any spectra of the jet showing
lines - optical or radio?".
If the speed is measured by trig and there are no spectra
available, what various people have asked is why you think
Transverse Doppler would be a factor.
George
Joseph Lazio
j> [...] surely the composition of that material is relevent? And that
j> is determined by spectra, which I am suggesting would be very
j> flawed data, were transverse doppler effects as posited.
Yes, the composition of the material is relevant. Unfortunately,
there are few means available to determine that. The spectra of the
jets are essentially a featureless continuum. There are no spectra
lines. Other than being reasonably confident that the emission is
synchrotron radiation, there's not a whole lot more that can be said.
jgr...@seol.net.au
The composition of an emitting source (say H) is assumed from its
emitted wavelength (as received by us). If that wavelength has been
altered by TD, then the composition of the source is assumed
incorrectly. I agree that this may not have anything to do with the
actual separation of the "top" from its origin- what I don't see taken
into consideration is say 25cm radiation being claimed to be H, because
the cloud is crossing our view (and therefore should have TD altered
wavelength).
SR supporters will be looking very hard for evidence that the angle is
NOT increasing as it seems- superlumenal material is anathema.
Optical effects / illusions may be the way for DHR's to try to
discredit
these superlumenal effects, but beware! They may be the same ones which
are used to SUPPORT SR, and return to savage their posteriors.
Jim G
c'=c+v
jgr...@seol.net.au
The composition of an emitting source (say H) is assumed from its
jgr...@seol.net.au
Joseph Lazio wrote:
> >>>>> "j" == jgreen <jgr...@seol.net.au> writes:
>
> j> [...] surely the composition of that material is relevent? And
that
> j> is determined by spectra, which I am suggesting would be very
> j> flawed data, were transverse doppler effects as posited.
>
> Yes, the composition of the material is relevant. Unfortunately,
> there are few means available to determine that. The spectra of the
> jets are essentially a featureless continuum. There are no spectra
> lines. Other than being reasonably confident that the emission is
> synchrotron radiation, there's not a whole lot more that can be said.
Fair enough, that a fast-moving mixture of atoms / molecules is just
"brown", and doesn't show lines. Pity really- it would be nice to see
whether the H atoms could travel faster than the Fe, or viceversa.
Jim G
c'=c+v
George Dishman
<jgr...@seol.net.au> wrote in message
news:1110069221.8...@g14g2000cwa.googlegroups.com...
<snip>
>> Jonathan asked "But are there any spectra of the jet showing
>> lines - optical or radio?".
>>
>> If the speed is measured by trig and there are no spectra
>> available, what various people have asked is why you think
>> Transverse Doppler would be a factor.
>
> emitted wavelength (as received by us).
You are assuming there exists a single emitted
wavelength. That is not the case for the radiation
produced by heated material, it glows at all
wavelengths. That is the case for the jets.
> If that wavelength has been
> altered by TD, then the composition of the source is assumed
> incorrectly. I agree that this may not have anything to do with the
> actual separation of the "top" from its origin-
There is no "top", just a continuous but
somewhat variable stream.
> what I don't see taken
> into consideration is say 25cm radiation being claimed to be H,
That is because there are no lines. Why don't you
just listen to what Jonathan and Joseph have been
telling you?
George
George Dishman
<jgr...@seol.net.au> wrote in message
news:1110069598.1...@g14g2000cwa.googlegroups.com...
OK, you did listen. Sorry for my previous comment.
best regards
George
Paul Hollister
>>>>>> "j" == jgreen <jgr...@seol.net.au> writes:
>
> j> [...] surely the composition of that material is relevent? And that
> j> is determined by spectra, which I am suggesting would be very
> j> flawed data, were transverse doppler effects as posited.
>
> Yes, the composition of the material is relevant. Unfortunately,
> there are few means available to determine that. The spectra of the
> jets are essentially a featureless continuum. There are no spectra
> lines. Other than being reasonably confident that the emission is
> synchrotron radiation, there's not a whole lot more that can be said.
What a fascinating subject this is. Although as a hematologist I spent most
of my life looking at the universe through a microscope rather than
telescope, the unique morphological pattern of the plasma jet exploding out
of the nuclear center of galaxy M87 has to have enormously relevant
structural and functional significance. In hematology, as a microscopist,
when we encounter a single aberrant cell in the bone marrow that is
difficult to identify, we can usually identify the nature of the cell line
by examining the company it keeps. As the characteristic features of certain
cell populations gradually transition toward their progenitors, it becomes
possible to morphologically identify how an individual cell transforms into
its present morphological appearance, structurally speaking. I therefore
looked at cosmic plasma jets in a variety of celestial objects and was
surprised by what I saw. These jets from quasars and the nuclear center of
galaxies consistently appear to be an integral part of their morphological
structure and physical ontogeny, rather than an aberrant result of a
catastrophic event. Obviously, visually speaking, these plasma jets are
exploding out of the nuclear centers of quasars and a wide variety of
interrelated galaxy types that have identical giant plasma jets. By aligning
these structures according to specific criteria including the presence of
jets, I was able to recognize that the quasar and its jettison of particle
plasma appeared to be forming the active nuclear center of all these
galaxies, which appear to extend as an interrelated structural continuum all
the way from quasar to radio galaxy to elliptical galaxies, exactly like
galaxy M87. This alignment indicates to me that the material flooding into
surrounding space is potentially composed of hydrogen, because the ongoing
expansion of this radio emitting material results in the formation of a
radio galaxy, wherein star birth is visibly vigorously active.
By looking at the process on either side of the jet in galaxy M87 (i.e.
within the supermassive density of the quasar at galaxy center and within
the massive radio structure that results from this ongoing process of
particle formation that is visibly flooding into surrounding space), the
composition of the material can be investigated in theoretical terms. Citing
evidence from recent reports about the supermassive "black hole" and plasma
jet exploding out of galaxy M87, by using a Gravity Implosion---Energy
Explosion Model analogous to stellar evolution, I have demonstrated how the
supermassive gravitational density of the quasar at galaxy center is
potentially the actual physical site of Ongoing "Big-Bang" nucleosynthesis
of hydrogen that results in formation of the circumnuclear torus and
jettison of hydrogen (proton-electron plasma) into surrounding regional
space. See Evidence of Ongoing-Big-Bang in Center of Every Active Galaxy at
http://www.origin-of-universe.com/chapters/chapter_10.htm
When the jets are modeled as newly formed hydrogen that transitions within
the cooler regions of surrounding space into ionic and atomic and molecular
hydrogen, the entire process of galaxy evolution unfolds from inside outward
as a result. See Illustration and concise summary of resulting Mainstream
Sequence of Galaxy Evolution at.
http://www.origin-of-universe.com/#Galaxy_Evolution
Respectfully,
Paul Hollister
http://www.Origin-of-Universe.com contains complete manuscript of
Origin and Evolution of the Universe, a Unified Scientific Theory
by Paul Hollister, M.D.
macro...@internetcds.com
we see them emiting enormous amounts of energy and matter.
But how exactly is this happening if the motion of everything
is falling at tremendous velocity toward the black hole?
What is giving the jets their outward push?
And why would it be only up through the poles?
How does matter arive at the poles first?
Mitch -- Light Falls --
Sam Wormley
> When we look at the black holes at the center of every galaxy
> we see them emiting enormous amounts of energy and matter.
>
> But how exactly is this happening if the motion of everything
> is falling at tremendous velocity toward the black hole?
Conservation of Angular Momentum
http://scienceworld.wolfram.com/physics/ConservationofAngularMomentum.html
macro...@internetcds.com
How, first, does matter arive at the poles?
mitch
Sam Wormley
macro...@internetCDS.com wrote:
> Why is it up through the poles only?
Conservation of Angular Momentum ==> accretion disk ==> friction ==> heating
And don't forget those magnetic fields.
macro...@internetcds.com
Sam Wormley
> How first does it arive at the bottom of the poles?
>
You best google accretion disk dynamics!
macro...@internetcds.com
How does it get there?
mitch
Mitch Perkins
> How does it first arive at the poles?
> How does it get there?
>
Sneaky Nitchky
Mitch
chosp
<macro...@internetCDS.com> wrote in message
news:1110349498.0...@l41g2000cwc.googlegroups.com...
> How does it first arive at the poles?
Late for dinner.
Not appropriately dressed.
> How does it get there?
Walks. Slowly.
Takes years.
Chris O'Riordan
I guess the features are too faint for spectral lines to be detected.
E.g, the 4c-6c superluminal globs in the M87 jet have ~10 Sun-masses
apiece, but are each dispersed over a volume of a few dozen cubic
parsecs.
It would be most interesting to obtain spectra for 3C273's jet. If, as
Thomson et al argued in 1993, the outer jet is nearly perpendicular to
the line of sight, the jet must -- to satisfy the beaming hypothesis --
almost turn a corner at some point, or else do some entertaining
convolutions. Or else the theory does ...
Jonathan Silverlight
Chris O'Riordan <cor...@hotmail.com> writes
>
>I guess the features are too faint for spectral lines to be detected.
>E.g, the 4c-6c superluminal globs in the M87 jet have ~10 Sun-masses
>apiece, but are each dispersed over a volume of a few dozen cubic
>parsecs.
>
>It would be most interesting to obtain spectra for 3C273's jet. If, as
>Thomson et al argued in 1993, the outer jet is nearly perpendicular to
>the line of sight, the jet must -- to satisfy the beaming hypothesis --
>almost turn a corner at some point, or else do some entertaining
>convolutions. Or else the theory does ...
>
apparently a "synchrotron continuum"
<http://www.cfht.hawaii.edu/Reference/Bulletin/Bull36/bulleti3.htm> and
the only useful information you can get is the slope of the spectrum
(look at <http://obswww.unige.ch/3c273/>, for instance - but I'm almost
out of my depth !)
Jim Greenfield
> In message <1111427524.1...@l41g2000cwc.googlegroups.com>,
> Chris O'Riordan <cor...@hotmail.com> writes
> >
> >I guess the features are too faint for spectral lines to be detected.
> >E.g, the 4c-6c superluminal globs in the M87 jet have ~10 Sun-masses
> >apiece, but are each dispersed over a volume of a few dozen cubic
> >parsecs.
> >
> >It would be most interesting to obtain spectra for 3C273's jet. If, as
> >Thomson et al argued in 1993, the outer jet is nearly perpendicular to
> >the line of sight, the jet must -- to satisfy the beaming hypothesis --
> >almost turn a corner at some point, or else do some entertaining
> >convolutions. Or else the theory does ...
> >
> Spectra have been obtained but they don't show any lines - they are
> apparently a "synchrotron continuum"
> <http://www.cfht.hawaii.edu/Reference/Bulletin/Bull36/bulleti3.htm>
If c'=c+v then radiation emitted from a jet of superlumenal material
of any approach angle to us which is positive will be visible, and of
an undetermined blue shift (as we don't know the emitted frequency at
source. EMR from a receding jet may be red shifted so much that it has
negative velocity to us, and the jet is invisible.........
........which explains precisely why only one of a likely pair of jets
is observed!
Jim G
c'=c+v
Joseph Lazio
JG> Jonathan Silverlight
JG> <jsilve...@spam.merseia.fsnet.co.uk.invalid> wrote in message
>>> It would be most interesting to obtain spectra for 3C273's jet.
>>> If, as Thomson et al argued in 1993, the outer jet is nearly
>>> perpendicular to the line of sight, the jet must -- to satisfy the
>>> beaming hypothesis -- almost turn a corner at some point, or else
>>> do some entertaining convolutions. Or else the theory does ...
>> Spectra have been obtained but they don't show any lines - they are
>> apparently a "synchrotron continuum"
>> <http://www.cfht.hawaii.edu/Reference/Bulletin/Bull36/bulleti3.htm>
JG> If c'=c+v then radiation emitted from a jet of superlumenal
JG> material of any approach angle to us which is positive will be
JG> visible, and of an undetermined blue shift (as we don't know the
JG> emitted frequency at source. EMR from a receding jet may be red
JG> shifted so much that it has negative velocity to us, and the jet
JG> is invisible......... ........which explains precisely why only
JG> one of a likely pair of jets is observed!
Of course, one can make a similar prediction within special
relativity. Highly relativistic material emits radiation into a
fairly narrow beam. If the beam is not pointed toward you, the
radiation from the material is strongly dimmed.