Superluminal Quasar Jets : The Beaming "Explanation" Appears Inadequate

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 a-

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.

Dear Chris O'Riordan:

"Chris O'Riordan" wrote in message
oups.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

Chris O'Riordan 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.




http://www.mhhe.com/physsci/astronom...r24/24f09.html
http://www.mhhe.com/physsci/astronom...r24/24f10.html

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:kPkTd.81133$Yu.56373@fed1read01...
Dear Chris O'Riordan:

"Chris O'Riordan" wrote in message
oups.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

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" wrote in message
news:flmTd.994$r55.269@attbi_s52...
"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:kPkTd.81133$Yu.56373@fed1read01...
Dear Chris O'Riordan:

"Chris O'Riordan" wrote in message
oups.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

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

Nevermind. For some reason I skipped the part about the spectra being
"reasonable". I understand now.

Thomas

In message kPkTd.81133$Yu.56373@fed1read01, "N:dlzc D:aol T:com
(dlzc)" writes
Dear Chris O'Riordan:

"Chris O'Riordan" wrote in message
roups.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.
--
Support the DEC Tsunami Appeal http://www.dec.org.uk/.
Remove spam and invalid from address to reply.

Dear Jonathan Silverlight:

"Jonathan Silverlight"
wrote in message ...
In message kPkTd.81133$Yu.56373@fed1read01, "N:dlzc D:aol T:com (dlzc)"
writes
Dear Chris O'Riordan:

"Chris O'Riordan" wrote in message
groups.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

"Chris O'Riordan" ha scritto nel messaggio
oups.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 a-

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

Dear Luigi Caselli:

"Luigi Caselli" wrote in message
...
"Chris O'Riordan" ha scritto nel messaggio
oups.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 a-

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.

.... which some consider desirable.

But they must also throw away Maxwell, since he allows light to leave these
"superlumenal" event.

David A. Smith

N:dlzc D:aol T:com (dlzc) wrote:

Dear Chris O'Riordan:

"Chris O'Riordan" wrote in message
oups.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