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Nick
http://www.physorg.com/news90776642.html

By definition these are absolute quantities.
AlphaNumeric
How so? The fine structure constant is a measure of how strong electrons feel one another's presence. If they feel one another less strongly as time passes then something is changing. Since the fine structure constant is defined in terms of the electric charge, Plancks constant, permittivity of free space and pi, then if it changes, one or more of those quantities must be changing, so no, they aren't absolute just because they seem to be.
rpenner
QUOTE (Nick+Feb 15 2007, 10:34 PM)
By definition these are absolute quantities.

In the Standard Model they are modeled as absolute quantities. Other physical theories do allow them to change over time. The universe is not an object constructed out of pure reason, so experiments and measurements are required to know anything. Over time, as data is accumulated, various models are rejected outright or modified by constraining the value of some parameter.
ERNRAM
Can someone tell me why this equation works (estimates the age of the earth to approxately 14 billion years) ?

t0 = (pi*(Gn * L)^1/2)^-1

t0 = Age of Universe (seconds)
Gn (Newton's Gravitational Constant) ~ 6.67x10^-11 m^3/kg*s^2
L (Cosmological Constant) ~ 0.74 x10^-26 kg/m^3

It seems to really have 2 constants which would somehow have to change for it to be true.

Thanks,
Ernie
rpenner
1) That's the age of the universe, not the Earth. The age of the Earth is about 5.5 billion years.

2) In SI units, the "Dark Energy Density", ρΛ, works out to be about: (0.685±0.055)×10^−26 kg/m³ (relative error = 0.09)

3) In SI units, the Age of the universe, t0, works out to be about: (4.33±0.04)×10^17 s (relative error = 0.011)

4) In SI units, the Gravitational constant, G, is about (6.6742±0.0010)×10^−11 m³/kg/s² (relative error = 0.00015)

So if t0 = k/sqrt(G×ρΛ) then k = t0×sqrt(G×ρΛ) = 0.29 with a relative error of 0.046 = 4.6%, so it's over 50 standard deviations from π.

Now it's still close because H0, the Hubble constant, is close to 1/t0 and in certain geometric units, the critical density of the universe is close to H0, and by measurement ρΛ is between 0.7 and 0.78 times this critical density, but it's nothing mystical.

http://en.wikipedia.org/wiki/Lambda-CDM_model
http://lambda.gsfc.nasa.gov/product/map/cu...ibliography.cfm
http://pdg.lbl.gov/2006/reviews/consrpp.pdf
ERNRAM
rpenner,

Thanks for the feedback.

The "earth" was a typo, and as shown in the definition for t0, which was correctly labeled as age of universe. See orginal posting.

I think you may be missing my points which are the following:

1. This equation is not something I copied from a website or a book, but something I derived.

2. The "constants" in the equation (Gravitational & Cosmological) would have to change for the age of the universe to continue to change. From my calculations if the Gravational constant was held constant, the Cosmological "constant" would have to decrease by about 14% over the next 1 billion years.

Ernie

mott.carl
the time rates are measure through of the variations of the universal constants that
are linkeds to the stretch and shrinking of the space.then the click of the clocks are
differents given by gravitational potential,and also by curvatures of spacetime that
are derived by deformations of distict energy states coupled,and measured by the
velocity,in the case the constant,that is variable in spacetime through of temporal exolution,then the curvatures of spacetime are whithin of non-linear structures.that modify with tick of the clocks and distortion of space,connected with G,e,h,H,and c...
rpenner
And I'm saying:
1) You missed a factor of 10
2) The data does not support your claim
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