Re: Old Stars

[jmclean@chem.ucsd.edu (James Mclean)]

Alex. F. Burr says:
>      During a close play at first base the 1st base man runs back and
> to his left to snag a ground ball. The pitcher runs to cover first.
> The first baseman tosses the ball toward 1st base even though the pitcher
> is not there yet. But the pitcher gets there befor the ball because it
> takes a while for the ball to get there. The ball comes from the
> direction of where the 1st baseman was when he threw it, not where he
> is when the pitcher catches it. Furthemore in the unlikely event that
> the 1st baseman wrote the time that he caught the ball on it before he
> threw it the pitcher would find it labled with the time it was fielded
> not the time it got to first base.

But, unlike the pitcher and 1st baseman, the galaxies are presumably all
moving away from the place where the big bang happened.

Say the 1st and 2nd basemen, after a conference at the pitcher's mound,
head back to their positions at the same time.  Say the 2nd baseman wants
to throw the ball so that the 1st baseman catches it as he arives at 1st
base.  He must wait for some time after leaving the mound.  He can not
throw the ball arbitrarily early, even if he chooses to walk off in some
other direction.

I kind of suspect that the answer to this question is related to how the
expanding universe is always depicted by drawing little galaxies on a
rubber baloon.  There is apparently no one location that is identifiable as
where the big bang happened.  However, I don't think I really understand
the analogy.  Can someone make this clearer?

Since the light has to travel along the surface of the baloon (not through
it's volume), I can see that you could see earlier times. Even back to
time zero if the light is allowed to go around the baloon multiple times.
Is that really a good analogy?

-- 
--James McLean
jmclean@chem.ucsd.edu
post doc
UCSD