Big Bang

In article ,
Jonathan Doolin writes:
What I would probably be interested in is developing a directional
model, which would be in line with the dipole anisotropy; I guess that
would be a simple rotation trasform, so right ascention and
declination became a polar and azimuthal angle in line with the dipole
axis.

Doing the coordinate rotation is easy.

Then I would look for explanations of a couple of anomolies:
http://www.astro.ucla.edu/~wright/sne_cosmology.html

Please, click on the link and look at the top graph. There appears to
be an outlier around 7 GPc

Only two sigma, if you look at the data table below the graph.

and then there is an extremely wide error
bar between 9 and 12 GPc.

Because there are few SNe observed at these distances.

This particular chart seems to top out at
c*z=3D500000km/s, which is z=3D5/3.

Bin centered at z=1.55 according to the table.

With data compiled by others, though, all I can really do is speculate
on what it means, but it still kind of seems to fit with this model.

I think you are way over-interpreting a statistical outlier, but I've
been wrong before. The question is whether the model you propose
fits the data at all. As you see on Ned's graph, there are eight
lines representing models, and only four fit the data. Where does
your model fall in the graph?

http://www.cfa.harvard.edu/supernova/SNarchive.html

This is the raw data, which you probably don't want. Instead, look
at Table 11 of Kowalski et al. (2008) he
http://arxiv.org/abs/0804.4142

The published version of the paper at
http://iopscience.iop.org/0004-637X/686/2/749/fulltext should become
public next month and has a machine-readable version of the table,
and I wouldn't be at all surprised if the table is already on the web
somewhere. However, Ned's compilation and averaging of the data
should be good enough to tell whether your model has a chance of
working or not.

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Steve Willner Phone 617-495-7123
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In article , I wrote:
at Table 11 of Kowalski et al. (2008) he
http://arxiv.org/abs/0804.4142

I see there's an update at
http://supernova.lbl.gov/Union/
with the full descriptive paper at
http://supernova.lbl.gov/Union/figur...2001_arXiv.pdf

I haven't looked at it in great detail, but the outlier seems to have
gone away with more data. The data tables are available via the
first link above.

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Help keep our newsgroup healthy; please don't feed the trolls.
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On Sep 8, 10:51*am, (Steve Willner) wrote:
In article , I wrote:
at Table 11 of Kowalski et al. (2008) he
http://arxiv.org/abs/0804.4142

I see there's an update athttp://supernova.lbl.gov/Union/
with the full descriptive paper athttp://supernova.lbl.gov/Union/figures/hst-2001_arXiv.pdf

I haven't looked at it in great detail, but the outlier seems to have
gone away with more data. *The data tables are available via the
first link above.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner * * * * * *Phone 617-495-7123 * *
Cambridge, MA 02138 USA * * * * * * * *

Hi Steve.

Question. In table 11. what do z, m, s, c, and mu represent? I'm
hoping they are related to right ascension, declination, redshift, and
luminosity distance.

On Sep 3, 8:27*am, Jonathan Doolin wrote:
On Sep 1, 3:22*pm, (Steve Willner) wrote:

In article ,
*Jonathan Doolin writes:

Not a fixed point--a fixed event. *A fixed "point" in space is
stationary in only one reference frame. *On the other hand, a fixed
event can be the center of an expanding sphere in any and every
reference frame.

OK, I see what you mean, I think. *There may still be a difficulty
with the cosmological principle -- that the Earth is not in any
special place -- but I'm not sure the model is ruled out on that
basis by existing observations.

SW What I asked you to compute was
SW a redshift-*distance* relation

We can do that now: the Hubble law distance is just proportional to
velocity, and I don't see why the luminosity distance (in a flat
Universe) wouldn't have the same 1+z correction as in the standard
model. *This is not the same distance law as the standard model
gives, but perhaps you could put in curvature or something to make it
agree. *Of course you also have to find agreement with such things as
the fluctuations in the microwave background.

What I would probably be interested in is developing a directional
model, which would be in line with the dipole anisotropy; I guess that
would be a simple rotation trasform, so right ascention and
declination became a polar and azimuthal angle in line with the dipole
axis.

Then I would look for explanations of a couple of anomolies:

http://www.astro.ucla.edu/~wright/sne_cosmology.html

Please, click on the link and look at the top graph. *There appears to
be an outlier around 7 GPc, and then there is an extremely wide error
bar between 9 and 12 GPc. *This particular chart seems to top out at
c*z=500000km/s, which is z=5/3.

With a high variation of distance, and a very low variation of
redshift, This would seem to indicate that there is a thick shell of
supernova that are all traveling away from us at essentially the same
speed.

I think that is consistent with some of the ascii space-time diagrams
I drew earlier, if we have scattering from multiple events, then the
shell of constant velocity would be fairly symmetrical.

* * * \ *\ * * * | * * * */ /
* * * *\ *\ * * *| * * * / /
* * * * \ *\ * */ * * */ /
* * * * * \ \ */ * * */ /
* * * * * *\ \/ * * */ /
* * * * * * \ \ * * / /
* * * * * * *\ \/\ / /
* * * * * * * \/ * \/
* * * * * * * *\ * /
* * * * * * * * \ /

...whereas if we have scattering from a more singular event, that
shell will be thinner on one side than the other:

* * * \ *\ * * | * * */ * * /
* * * *\ *\ * *| * * / * * /
* * * * \ *\ * | * */ * * /
* * * * * \ \ */ * / * */
* * * * * *\ \/ * / * */
* * * * * * \ \ */ * */
* * * * * * *\ \/ * */
* * * * * * * \/ * */
* * * * * * * *\ * /
* * * * * * * * \ /


I've produced a much better diagram at

http://www.physicsforums.com/showthr...92#post2887692

Post #94

For an explanation of the outlier at the 7 GPc mark; you have a region
where you have a fast-moving surface of supernovae--all much closer
than would otherwise be expected. *That points to a recent event; an
explosion which "created" our local universe. *Those events would
probably constitute the latest division in either of my space-time
diagrams above.

With data compiled by others, though, all I can really do is speculate
on what it means, but it still kind of seems to fit with this model.

Basically, either your model will give the same predictions as the
standard model -- in which case why bother? -- or it will give
different ones. *If the latter, it would be rather surprising for
them to agree with observations, given how well the standard model
fits everything. *But I've been wrong before, so feel free to do the
math and compare with observation.

SW I doubt very much it will agree with
SW observation (principally the supernova results).

I don't have access to much of that data.

The supernova data, at least a good quantity to work with, are online
in nicely calibrated form.

Ostensibly, that data is available he

http://www.cfa.harvard.edu/supernova/SNarchive.html

If I were a computer hacker, maybe I would be able to access it.

Jonathan Doolin *They have the Hubble Deep Field in two extremely narrow paths HDF
North and HDF South,

I'm not sure there are _any_ SNe in the deep fields, but there are
surely not many.

Other than the above comments on the astronomy, I'll suggest that if
you want to learn relativity, you should get a textbook. *Or more
than one. *One of the best suggestions I was ever given was that
(special) relativity is tricky the first time you see it, and it's
very helpful to have the same equations explained in different words.
As I recall, some of the books I personally found most helpful were
written by Minkowski in the 1930s, but my memory may be faulty about
the author and/or the date. *Anyway _for me_, the older books were
more helpful than newer ones, but it could easily be the reverse for
someone else.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner * * * * * *Phone 617-495-7123 * *
Cambridge, MA 02138 USA * * * * * * * *