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From: Uncle Al on 22 Jun 2010 10:40
"vincent64(a)yahoo.com" wrote:
>
> On Jun 21, 5:04 pm, Sam <sworml...(a)gmail.com> wrote:
> > On Jun 21, 6:57 pm, "vincen...(a)yahoo.com" <datashap...(a)gmail.com>
> > wrote:
> >
> > > Assuming that the Universe is compact and expanding at a constant rate
> > > in all directions, and using a model of the Universe that seems
> > > reasonable:
> >
> > > 1) Can we measure the minimum speed v at which a particle must move
> > > (assuming it is moving in the same direction in a curved Universe), in
> > > order to come back indefinitely to its initial position?
> >
> > There is no absolute reference frame.
> >
> > No Center
> > http://www.astro.ucla.edu/~wright/nocenter.html
> > http://www.astro.ucla.edu/~wright/infpoint.html
> >
> > Also see Ned Wright's Cosmology Tutorial
> > http://www.astro.ucla.edu/~wright/cosmolog.htm
> > http://www.astro.ucla.edu/~wright/cosmology_faq.html
> > http://www.astro.ucla.edu/~wright/CosmoCalc.html
> >
> > WMAP: Foundations of the Big Bang theory
> > http://map.gsfc.nasa.gov/m_uni.html
> >
> > WMAP: Tests of Big Bang Cosmology
> > http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html
>
> How can you have no center and either expand or collapse:
[snip]

EVERY point in the universe is at its exact center. All 4(pi)
steradians exactly point to an equidistant Big Bang.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz4.htm
From: vincent64 on 22 Jun 2010 17:06
On Jun 22, 7:07 am, Igor <thoov...(a)excite.com> wrote:
> On Jun 21, 8:42 pm, "vincen...(a)yahoo.com" <datashap...(a)gmail.com>
> wrote:
>
>
>
>
>
> > On Jun 21, 5:04 pm, Sam <sworml...(a)gmail.com> wrote:
>
> > > On Jun 21, 6:57 pm, "vincen...(a)yahoo.com" <datashap...(a)gmail.com>
> > > wrote:
>
> > > > Assuming that the Universe is compact and expanding at a constant rate
> > > > in all directions, and using a model of the Universe that seems
> > > > reasonable:
>
> > > > 1) Can we measure the minimum speed v at which a particle must move
> > > > (assuming it is moving in the same direction in a curved Universe), in
> > > > order to come back indefinitely to its initial position?
>
> > >   There is no absolute reference frame.
>
> > >   No Center
> > >    http://www.astro.ucla.edu/~wright/nocenter.html
> > >    http://www.astro.ucla.edu/~wright/infpoint.html
>
> > >   Also see Ned Wright's Cosmology Tutorial
> > >    http://www.astro.ucla.edu/~wright/cosmolog.htm
> > >    http://www.astro.ucla.edu/~wright/cosmology_faq.html
> > >    http://www.astro.ucla.edu/~wright/CosmoCalc.html
>
> > >   WMAP: Foundations of the Big Bang theory
> > >    http://map.gsfc.nasa.gov/m_uni.html
>
> > >   WMAP: Tests of Big Bang Cosmology
> > >    http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html
>
> > How can you have no center and either expand or collapse: if you have
> > no center, then from where are you expanding - from which reference
> > point?
>
> Any reference point.  The surface of a sphere has no center, yet it
> can expand.  Points on the surface appear to move away from each other
> and any point is as good as any other.


This link below will tell you how to compute the center of a sphere
surface:
http://mathworld.wolfram.com/Sphere.html

Keep in mind that you are talking about mathematical models of the
universe. These are just models and approximation of the real world.
Nevertheless, a sphere center has a center.

>
> >You can expand and have no center if you are not compact
> > (meaning e.g. that the average distance between 2 closest neighboring
> > stars is increasing over time, on average), but if you believe that
> > the universe is not compact, then how do you explain the big bang? Was
> > the universe compact (finite) when the big bang happened, and
> > suddenly, one day the universe became infinite (non compact)?
>
> No one has recently suggested the universe is infinite.  In fact,
> Olbers showed it can't be infinite based on what we understand about
> light in a very clever paradox.  Modern cosmology, based on GR,
> suggests that the universe is finite but unbounded (like the fore-
> mentioned spherical surface).- Hide quoted text -
>
> - Show quoted text -

From: Sam on 22 Jun 2010 20:58
On Jun 22, 4:06 pm, "vincen...(a)yahoo.com" <datashap...(a)gmail.com>
wrote:

>
> Keep in mind that you are talking about mathematical models of the
> universe. These are just models and approximation of the real world.
> Nevertheless, a sphere center has a center.
>
>

Every Point is the center of the expansion.

No Center
http://www.astro.ucla.edu/~wright/nocenter.html
http://www.astro.ucla.edu/~wright/infpoint.html

Also see Ned Wright's Cosmology Tutorial
http://www.astro.ucla.edu/~wright/cosmolog.htm
http://www.astro.ucla.edu/~wright/cosmology_faq.html
http://www.astro.ucla.edu/~wright/CosmoCalc.html

WMAP: Foundations of the Big Bang theory
http://map.gsfc.nasa.gov/m_uni.html

WMAP: Tests of Big Bang Cosmology
http://map.gsfc.nasa.gov/m_uni/uni_101bbtest.html
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