The Local Group of Galaxies

[webolife]

I am curious about the local group of galaxies depicted in the introductory graphic of Thomas Wilson's recent TPOD series.
What is the redshift info on these nearest galaxies? Do the redshifts support Arp's hypothesis, or as I assume from the way standard astronomical distancing is done, are these assumed to be our neighbors based on their similar, low redshifts?
I've looked at the Nov 4 2005 TPOD for a comparative discussion, and am unsure how the two pictures correlate...
I could use some expert clarification on this...anyone?

[Steve Smith]

Distances in the Local Group are all measured by redshift, since the galaxies are too far away for parallex measurements.

Distances of the Local Group member galaxies, from various sources

I'm not sure what you mean by the redshifts supporting Arp's hypothesis. According to Arp, redshift is an inherent characteristic of matter and not a measurement of recessional velocity. Who knows how far away they are?

[nick c]

Also, [url2=http://imagine.gsfc.nasa.gov/docs/scien ... pheid.html]Cepheid variable[/url2] stars are the main method used to estimate the distances of nearby galaxies:

http://adsabs.harvard.edu/abs/1985EdES...38..127S

Parallax is only useful for nearby stars, within the Milky Way.
Beyond the Local Group, supernova estimates, globular clusters, and the Red Shift (Hubble Constant) are the primary means of estimating distance.

Tools used for distance measurements in astronomy:
http://hyperphysics.phy-astr.gsu.edu/Hb ... ce.html#c1


nick c

[Steve Smith]

Variable stars are not an accurate measuring stick.

See: Variable Stars

[nick c]

Steve,
I'm with you there, you're preaching to the choir.
My post was only relating how astronomers calculate the distances we commonly see in mainstream material. Cepheids are the main tool astronomers use for measuring distances to nearby galaxies.
We also know that the redshift is not reliable but, again, that is the (main long distance) tool that they use.
So, in reality astronomers are assuming a degree of precision which is not justified and we are left with only rough estimates of distance; such as estimates of the absolute luminosity of globular clusters, nova and supernova, as compared to their apparent luminosity, etc.
"See that galaxy there, it's precisely... very far away!"

nick c

[webolife]

I'm with both Steve and Nick on this issue... but that leaves my original quest[ion] unsatisfied...
What is the connection in concept between Thomas Wilson's graphic and that from Arp's work shown on TPOD Nov 4,2005?

[webolife]

(Late edit):

I'm with both Steve and Nick on this issue... but that leaves my original quest[ion] unsatisfied...
What is the connection in concept between Thomas Wilson's graphic and that from Arp's work [and accompanying explanation] shown in TPOD Nov 4,2005? One shows scattered galaxies in somewhat of a "halo" about the Milky Way, the other has a much more linear array...both supposedly built from redshift reference material. I'm having trouble synthesizing a relationship between the two. I have disputed the Cepheid concept for over 20 years, and the redshift for nearly 30, so that is not the key issue for me.

[nick c]

Hi webolife,

What is the connection in concept between Thomas Wilson's graphic and that from Arp's work [and accompanying explanation] shown in TPOD Nov 4,2005? One shows scattered galaxies in somewhat of a "halo" about the Milky Way, the other has a much more linear array...both supposedly built from redshift reference material.

I think that I understand the issue you are raising. Maybe not. At the risk of answering the wrong question...
the graphic in the [url2=http://www.thunderbolts.info/tpod/2009/ ... tolemy.htm]Feb 4, 2009[/url2] TPOD depicts the immediate environment of the Milky Way. The graphic is a product of mainstream astronomy. All the galaxies in the graphic are satellite dwarfs surrounding the Milky Way. The graphic has little to do with Arp's theory but is put in as a reference showing the mainstream view of our immediate galactic environment. The text goes on to draw a comparison between the Ptolemaic theory of the solar system with all its' ad hoc add ons (epicycles, spheres within spheres) and the current state of cosmology with all its' ad hoc add ons (dark matter, dark energy, singularities, etc.)
The TPOD of [url2=http://www.thunderbolts.info/tpod/2005/ ... lgroup.htm]November 4, 2005[/url2] depicts on a 2d graph a larger section of the Local Group, where as the Feb 4, 2009 TPOD graphic is on a much smaller scale, showing the dwarf satellite galaxies of the Milky Way. Note that M31, the Great Andromeda Galaxy, is not in the Feb 4 TPOD graphic, that is because it is much farther out than could fit in the depicted cube of space. So the line of galaxies that Arp talks about may be obscured because the graphic is just on too small of a scale, a few hundred thousand light years. Whereas, M31 is 2.5 million light years (again mainstreams' numbers) away.
Also, on the Feb 4, 2009 graphic, the galaxies are named by the constellation they occupy, rather than their catalog (NGC or Messier) number, which adds to the confusion.
I think the Nov 4, 2005 graph is put in to show Arp's thought that the local group stretches in a line to M31, it is Arp's graph. The Feb 4, 2009 graphic is a mainstream construction. Perhaps that is another source of conflict in addition to the scale issue.
As I wrote in my other posts, these distances were most likely arrived at by observations of Cepheid Variables, as that is the main tool for measuring distances in our galactic neighborhood. So the validity of that technique would affect the accuracy of any graphic representations.

nick c

[webolife]

Yes, you have clarified the reasons for my question... I also saw these differences, but I'm stilll interested in hearing the connection in concept. Arp's contention, as you also reviewed, is that the local galaxies stretch somewhat linearly between us and Andromeda, a very interesting observation, if it is actually true; but I was unsure as to whether I might be misunderstanding the graphics. I'm much more familiar with the standard array of the satellite galaxies, and am equally cautious about assumptions regarding their distance, but would be interested in a further synthesizing of the two views, of course from the EU perspective.