Hubble deep field question

I'm reading "Chasing Hubble's Shadows" by Jeff Kanipe, and he
states on page 140 that "blobjects" at redshift 6 that were
13,000 light years across would appear 0.2 seconds of arc in
size. But that's assuming the light left when the object was 12.7
billion light years away.

I had thought that the objects would have been much closer when
the light first left and it took 12.7 billion years to reach us because
of cosmic expansion, which would not have made the objects look
smaller.

At redshift 6 they would be traveling at about 0.9c, but how would
you figure out how far away they were when the light first left from
that? I thought it would be 1/6 * 12.7bly, but that's assuming the
author is wrong, which may not be warranted.

--
Craig Franck

Cortland, NY

"Craig Franck" wrote in message
...
I'm reading "Chasing Hubble's Shadows" by Jeff Kanipe, and he
states on page 140 that "blobjects" at redshift 6 that were
13,000 light years across would appear 0.2 seconds of arc in
size. But that's assuming the light left when the object was 12.7
billion light years away.

I had thought that the objects would have been much closer when
the light first left and it took 12.7 billion years to reach us because
of cosmic expansion, which would not have made the objects look
smaller.

At redshift 6 they would be traveling at about 0.9c, but how would
you figure out how far away they were when the light first left from
that? I thought it would be 1/6 * 12.7bly, but that's assuming the
author is wrong, which may not be warranted.

--
Craig Franck

Cortland, NY
Nobody sane would take seriously the so-called "Big Bang" creation theory,
yet the apparent red shift of distant galaxies is perplexing.

However, if one takes the Principle of Relativity seriously one is compelled
to accept a variation in the speed of light that is source velocity
dependent,
and with a little study one can soon realise that what works for one star in
a galaxy must work for them all.

This diagram:
http://www.androcles01.pwp.blueyonder.co.uk/Doolin'sStar.GIF

is for one star, and one can quickly see that dT is greater than dt
for most of the period. For a distant galaxy at the appropriate distance,
ALL stars will show a red shift MOST of the time. So statistically, red
shift is exactly what is to be expected for a galaxy without any
recessional velocity.

Attempting to gather light from a single star in a galaxy is an
impossibility, even the closest appears as a blur.
http://antwrp.gsfc.nasa.gov/apod/ap090109.html

In other words if your theory is that the speed of light is fixed
and what you see isn't illusion then you'll forever run into ever-
increasing conundrums such as objects being 13,000 light years
across!

Dear Craig Franck:

"Craig Franck" wrote in message
...
I'm reading "Chasing Hubble's Shadows" by Jeff
Kanipe, and he states on page 140 that "blobjects"
at redshift 6 that were 13,000 light years across
would appear 0.2 seconds of arc in size. But that's
assuming the light left when the object was 12.7
billion light years away.

No,, that assumes the objects look to be 12.7 Gly away "now".

I had thought that the objects would have been
much closer when the light first left and it took
12.7 billion years to reach us because of cosmic
expansion, which would not have made the
objects look smaller.

.... and hence further away, and with the correct intensity.

At redshift 6 they would be traveling at about
0.9c,

No. A Z of 1 is "receeding" at c.

http://www.astro.ucla.edu/~wright/cosmo_01.htm
.... the text below the little sketch with the text "You're
receding"

but how would you figure out how far away they
were when the light first left from that? I thought it
would be 1/6 * 12.7bly, but that's assuming the
author is wrong, which may not be warranted.

I think you are trying to get to a number that has little
meaning.

David A. Smith

On Jan 22, 5:55*pm, "Craig Franck" wrote:
I'm reading "Chasing Hubble's Shadows" by Jeff Kanipe, and he
states on page 140 that "blobjects" at redshift 6 that were
13,000 light years across would appear 0.2 seconds of arc in
size. But that's assuming the light left when the object was 12.7
billion light years away.

I had thought that the objects would have been much closer when
the light first left and it took 12.7 billion years to reach us because
of cosmic expansion, which would not have made the objects look
smaller.
....

Under the standard cosmologies, this is true. For example, see
http://en.wikipedia.org/wiki/Angular_diameter_distance
Beyond a redshift of about 1-2 objects of the same physical size start
to grow *larger* in apparent angular size.

Craig

On Thu, 22 Jan 2009 17:00:01 -0700, "N:dlzc D:aol T:com \(dlzc\)"
wrote:

Dear Craig Franck:

"Craig Franck" wrote in message
snip

No. A Z of 1 is "receeding" at c.

I beg to differ. This is a common and grievous error, if we attribute
redshift to straight Doppler. The laboratory measurement is
L'/L = 1 + z
Letting v/c = b (for beta), doppler causes the frequency reduction
f'/f = 1 - b
from which the wavelength is given by the inverse
L'/L = 1/1-b = 1 + b + b^2 + b^3 which is not 1 + z
z is not v/c.
A little algebra shows that recession velocity is given by
c*z/1+z, so for z = 1, the recession is c/2.
I think this has been lost sight of in the current fiction
that space stretches wavelengths by 1+z, a concept which panders to
Einsteins space-time.
I see the graphs that routinely present v/c1 with velocities
equal to 2 and 3c. It isn't true, and this is the reason, which should
come as a great relief, since viewing c is impossible.

http://www.astro.ucla.edu/~wright/cosmo_01.htm
... the text below the little sketch with the text "You're
receding"

David A. Smith

John Polasek

"John Polasek" wrote in message
...
On Thu, 22 Jan 2009 17:00:01 -0700, "N:dlzc D:aol T:com \(dlzc\)"
wrote:

Dear Craig Franck:

"Craig Franck" wrote in message
snip

No. A Z of 1 is "receeding" at c.

I beg to differ. This is a common and grievous error, if we attribute
redshift to straight Doppler. The laboratory measurement is
L'/L = 1 + z
Letting v/c = b (for beta), doppler causes the frequency reduction
f'/f = 1 - b
from which the wavelength is given by the inverse
L'/L = 1/1-b = 1 + b + b^2 + b^3 which is not 1 + z
z is not v/c.
A little algebra shows that recession velocity is given by
c*z/1+z, so for z = 1, the recession is c/2.
I think this has been lost sight of in the current fiction
that space stretches wavelengths by 1+z, a concept which panders to
Einsteins space-time.
I see the graphs that routinely present v/c1 with velocities
equal to 2 and 3c. It isn't true, and this is the reason, which should
come as a great relief, since viewing c is impossible.

http://www.astro.ucla.edu/~wright/cosmo_01.htm
... the text below the little sketch with the text "You're
receding"

David A. Smith

John Polasek

Either the galaxies are speeding up or the light from them is slowing down.
The former requires dork energy, the latter a better understanding of
light's (and human) behaviour.

"Hubble had confused two different kinds of Cepheid variable stars used for
calibrating distances" says it all.
http://www.androcles01.pwp.blueyonder.co.uk/Doolin'sStar.GIF

On Sat, 24 Jan 2009 07:42:20 -0000, "Androcles"
wrote:

Either the galaxies are speeding up or the light from them is slowing down.
The former requires dork energy, the latter a better understanding of
light's (and human) behaviour.

If the value of c changes it changes the value of the fine structure
constant and that affects emission and absorption lines in spectra. No
such change seems to be visible.

Bud

"William Hamblen" wrote in message
...
On Sat, 24 Jan 2009 07:42:20 -0000, "Androcles"
wrote:

Either the galaxies are speeding up or the light from them is slowing
down.
The former requires dork energy, the latter a better understanding of
light's (and human) behaviour.

If the value of c changes it changes the value of the fine structure
constant and that affects emission and absorption lines in spectra. No
such change seems to be visible.

Bud

Ok. Changing the value of pi affects the ratio of the circumference
of a circle to its diameter. No such change seems to be visible.

Change the value of the fine structure constant so that you affect
emission and absorption lines in spectra, then publish your results.

****ing dork!

Dear John Polasek:

On Jan 23, 9:51*pm, John Polasek wrote:
On Thu, 22 Jan 2009 17:00:01 -0700, "N:dlzcD:aol T:com \(dlzc\)"

wrote:
Dear Craig Franck:

"Craig Franck" wrote in message
snip

No. *A Z of 1 is "receeding" at c.

I beg to differ. This is a common and grievous
error, if we attribute redshift to straight Doppler.

The Universe has no unique center, therefore the expansion is not from
an explosion in space. So there is no theoretical support to your
"manipulations".

David A. Smith

"dlzc" wrote in message
...
Dear John Polasek:

On Jan 23, 9:51 pm, John Polasek wrote:
On Thu, 22 Jan 2009 17:00:01 -0700, "N:dlzcD:aol T:com \(dlzc\)"

wrote:
Dear Craig Franck:

"Craig Franck" wrote in message
snip

No. A Z of 1 is "receeding" at c.

I beg to differ. This is a common and grievous
error, if we attribute redshift to straight Doppler.

The Universe has no unique center, therefore the expansion is not from
an explosion in space. So there is no theoretical support to your
"manipulations".

David A. Smith
================================
David A. Smith has no brain, therefore what he says has no meaning.
So there is no factual support to your "rambling rants".