In a message dated 11/11/00 1:29:07 AM,
[EMAIL PROTECTED] writes:
<< Another model is a loaf of raisin bread rising. The raisins are the
galaxies (or, probably more accurately, clusters of galaxies). As the
bread rises, say it doubles in diameter in one hour. Then the distance
between any two raisins also doubles during that hour. If two raisins
were, say, 5 cm apart at the start, they would be 10 cm apart an hour
later, and the average velocity of separation would be 5 cm/hour. Two
raisins that were 10 cm apart at the start would be 20 cm apart at the end,
and would be separating at 10 cm/hour, and so on, so the velocity is
proportional to the distance between the raisins, which is the same thing
we see with Hubble's law v=Hd. >>
Are the raisins themselves expanding? I mean, are the raisins themselves
getting bigger? (Not the raisins in the loaf, but the galaxies themselves,
and the individual stars within the galaxies.)
Distance is, from a perceptual point of view, also proportional, in this
case, to the size of the separated objects. A five-foot gap looks much
larger to an ant than to a human being. If you double it to a ten-foot gap,
it looks larger still - unless both the ant and the person have similarly
gotten bigger (even if they don't realize it - I'm not suddenly 11 foot six!)
Tom Beck
