In message , Aladar
writes
"William C. Keel" wrote in message
...
[...]

The concern is that Cepheid properties might vary somewhat

[...]


Still, it's always really really good to check important conclusions
in as many ways as one can.

Bill Keel

I wonder how could Hubble come-up with a 500 km/s per Mpc value from
the same thing, which is now used to support a 72(!) km/s per Mpc?



According to Gale Christianson's "Edwin Hubble: Mariner of the Nebulae"
he later revised it _upwards_ to 558 km/s/Mpc.
He was only using a very limited data set, of relatively bright and
close galaxies (46 in 1929). The fact that there were two different
types of Cepheids was announced over 20 years later, and doubled the
distance scale.
I'm sure his measurements are available somewhere.
I haven't (yet ?) been able to confirm this, but I wonder if the reason
that he considered a cause for the red shift other than recession was
that he was aware that the figure he found meant that the universe was
less than 2 billion years old, which was known to be absurd. A figure of
50 to 100 doesn't have this problem.
--
Rabbit arithmetic - 1 plus 1 equals 10
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