Cosmological Redshift and Expansion of Space

Right-it is a way to measure redshift developed by a lawyer from observations he made but what is the force causing the observed effect if not acceleration? And why is the Hubble Constant writen in obscure acceleration units?

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />what is the force causing the observed effect if not acceleration?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The cause of redshift is theory-dependent. In the Big Bang, it is expansion, a Doppler effect. In MM, it is friction from gravitons causing lightwaves to lose energy as they propagate.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">And why is the Hubble Constant written in obscure acceleration units?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Look again. It is not in acceleration units. Commonly, it is expressed in kilometers per second per megaparsec. The first and third of these are units of length. By making those two length units the same, length cancels out of the Hubble constant, and we see that its true dimensions are simply 1/time (reciprocal time). That is why the inverse of the Hubble constant is a time, which in BB is the age of the universe, and in MM is the time for a lightwave to lose 63% of its remaining energy. (The percentage comes from 1/e, if you are familiar with exponential decay.) -|Tom|-

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by tvanflandern</i>
<br /><blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />what is the force causing the observed effect if not acceleration?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">The cause of redshift is theory-dependent. In the Big Bang, it is expansion, a Doppler effect. In MM, it is friction from gravitons causing lightwaves to lose energy as they propagate.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
We can try various origins for the loss of energy of light. The simplest one is interactions with ordinary matter. This simplest solution has an advantage: the redshift has a dispersion (the relative frequency shift varies in the spectrum, this variation being considered in the big bang theory as due to an acceleration of the expansion). Dispersions are common in light matter interactions, for instance in refraction.
Many physicists tried incoherent Raman scatterings. The incoherent scatterings, studied in the 19th century for the theory of the blue of the sky, require fluctuations of density to introduce the phaseshifts which give the incoherence. In low pressure gas, these fluctuations correspond to collisions. In a given volume, the number of binary collisions is proportional to the square of the pressure, so that the scattered intensity is proportional to this square, negligible if the pressure has the values of interstellar gas. An other problem with incoherent scattering is that it blurs the images and the spectra.
Coherent scattering, on the contrary, is destroyed by the collisions, therefore works well at low pressures; it is much more intense than incoherent scattering. To get the coherence, the physicists use, in the labs, lots of tricks, for instance two indices of refraction of a crystal. G. L. Lamb gave "conditions" which allow the coherence without any apparatus, which therefore work in space. It is the CREIL effect. Lamb's conditions require a low pressure and convenient Raman frequencies available in excited atomic hydrogen; the energy lost by the redshift is usually transferred by an other Raman coherent scattering bound to the first one, to radio (thermal) radiation. It is remarkable that the three following observations are connected:
- Presence of excited atomic hydrogen mainly produced by the extreme UV radiated by an extremely hot star (supernova, quasar)
- High redshift
- Relatively high temperature of the thermal emission.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jim</i>
<br />The Hubble constant is what exactly? I assume its acceleration but no one agrees with that, so what is it?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

The notion 'Hubble constant' is actually a bit of a misnomer, as Hubble himself never fully shared the interpretation of the redshift as a recession velocity (see home.pacbell.net/skeptica/edwinhubble.html ). Strictly speaking, Hubble only showed that the redshift increases linearly with distance (that it increases at all, was already known before), and in this sense, the Hubble constant merely indicates how strong this increase with distance is. The interpretation of the redshift as a recession velocity (let alone as an expanding space) has as such nothing to do with Hubble.

Thomas

The simple fact is a lightyear or parsec is a unit of time as well as a unit of distance. So, if you look again using units of time rather than units of distance the constant appears as acceleration and the 1/e is a model dependant function. Models have a way of hiding the truth and all the math is smoke and mirrors. They use H^2 as if that means something too. Does that one fit into the MM?

About light loosing energy due to redshift: it could be this too is a result of modeling and not a real effect. The Planck bundle would loose energy but that in no way means energy is lost along the way. This happens because models misuse data and all photons may have the exact energy while the Planck bundle is billions of photons that is handy just as a kilogram is handy.