“SQM also suggests the possibility that past steps along our evolutionary ancestry may be so rare, that they have occurred no where else in the past history of the universe that we can observe”.

It is almost certain that life in the universe is a common phenomenon. It is also almost impossible that beings identical to ourselves exist anywhere else. One does not have to be a quantum theorist to fathom that! However it is interesting that certain quantum theories point to such an obvious conclusion about our uniqueness in the universe.

For similar reasons, related to genetic inheritance and environmental upbringing, each human individual who has ever lived is also unique. Cloning people doesn’t produce robots, just individuals with identical genetic inheritance- as identical twins. However, no pair of identical twins live exactly identical lives.

This comment in Don’s abstract has profound implications…

If anybody is into non-verbals, look at the expressions on Albert and Edwins faces!

A picture is truly worth 1,000 words!

I realize the picture was posed…for all we know it was taken in the daytime.

As for hard spheres in the contracting universe: the point is, not how they affect the forces, but they are an obstruction – I don’t think they could be just pulverized as if nothing there. There are contradiction problems if you try to imagine what happens to all the bodies in expanding/contracting universes if some things are impeded by material barriers/obstructions and other things just move like dust in free fall.

Garth: H_o*t_o is not equal to 1 with an accuracy of 0.6%.
t_o is known (but model dependent) to 1% and H_o (also
model dependent) to 4%. So while the product is very close to 1, the propagated uncertainy is 4%.

Yes Ned, although my post #22 was submitted before it was properly prepared (I have you Preview button on this Forum), I was simply using your Cosmology Calculator http://www.astro.ucla.edu/~wright/CosmoCalc.html,.

The present best accepted values of cosmological parameters
(using the table in WMAP Cosmological Parameters http://lambda.gsfc.nasa.gov/product/map/dr2/params/lcdm_all.cfm)
Ho = 70.4 km/sec/Mpsc
Omega_Lambda = 0.732
Omega_matter = 0.268

Feeding these values into your calculator I obtain:
The age of the universe is = 13.81 Gyrs.
But with h_100 = 0.704,
Hubble Time = 13.89 Gyrs. i.e. 0.6% difference!

In other words the calculated age turns out to be equal to Hubble Time to within the limits of the observational error of 4%.

Is this just a coincidence or is the universe trying to tell us something?

Garth

The discovery of the Hubble expansion was indeed a profound advance. But there’s even more to it than that, as you well know, so let me point out for your readers:

1. The pattern of Hubble’s law, that the recessional velocity of distant galaxies is proportional to their distance away, directly implies that contemporary observers on any galaxy will see the same pattern, and with the same proportionality. Thus the Hubble law contains the idea that the expansion has no preferred center.

2. If we extrapolate the Hubble-law motions of the galaxies backward, assuming no acceleration (a not entirely unreasonable thing to do), we discover that there was a singular moment at a finite time into the past when they were all on top of each other. So Hubble’s law also raises directly the idea of a Universe with finite age.

Hubble could/would have declared an expanding Universe based on any observation of velocity going up monotonically with distance. It is the special linear result v=Hd that also leads to the also profound picture of a uniform expansion with a finite history. It all came in the same package! as long ago as 1930, for which we can indeed be thankful.

Cheers,

Paul

Garth: H_o*t_o is not equal to 1 with an accuracy of 0.6%.
t_o is known (but model dependent) to 1% and H_o (also
model dependent) to 4%. So while the product is very close to 1, the propagated uncertainy is 4%.

Sean: I read Luminet’s review (pointed out by Daniel Fischer)
and it makes the point that Le Maitre’s little cited 1927 paper
in French to the Belgian Academy actually did the data analysis
and derived the Hubble constant two years before Hubble. Then
Luminet didn’t list this paper in his reference list! I wish
this 1927 paper were in the ADS, but last time I checked only
the translation in the 1931 MNRAS was there.