Re: lorenz transformation and spped of light

On Sep 23, 6:37 pm, "JM Albuquerque" <jmDO...@xxxxxxx> wrote:
"PD" <TheDraperFam...@xxxxxxxxx> escreveu na mensagemnews:1190586491.552346.91620@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Sep 23, 4:17 pm, "JM Albuquerque" <jmDO...@xxxxxxx> wrote:
"The Draper family" <TheDraperFam...@xxxxxxxxx> escreveu na
mensagemnews:C31B5A23.E7D8%TheDraperFamily@xxxxxxxxxxxx
I rest my case.

I agree with you.

So why chose and earth centred point of view and jump
to conclusions about a Big Bang, simply because it looks so
taken our special point of view here on earth?

We don't choose an earth-centered view. The big bang looks just the
same from any point in the universe. This, in this case, is an
"invariant event", for lack of a better term. It would be the same
conclusion drawn by any observer in this universe.

If so, what comes to my mind imediatly is that the universe
has to be infinite, because from every point in the universe
the big bang looks the same, so that I can be one billion LY
away, or 2, 3, 4, 5...., up to 13.7 BLY and I still would see
the big bang, like if I'm in the center of the universe.

Can you get the picture?

Maybe. A couple of comments:

You have in your mind that a space without a boundary must be
infinite. That's incorrect. Some simple examples follow but please
keep your brain within the dimensionality of the example.
1. In 1D, a line segment or a portion of a curve is both finite and
has a boundary (the end points). But a circle (which is still as 1D as
a line segment) is still finite but has no boundary.
2. In 2D, a *** or a portion of a hyperboloid is both finite and has
a boundary (the curve that bounds the ***). But the surface of a
sphere (which is still as 2D as a ***) is finite and has no
boundary.
3. It is a simple matter to extend the same idea to 3D and 4D, to find
spaces that are both finite and have no boundaries. An interesting
question to ask about the 1D and 2D cases is how you can recognized
those finite and boundaryless cases *without* embedding them in a
higher-dimensionality space to examine them. (It certainly is
possible, in fact it's quite straightforward.) Once you figure that
out, then you can apply the same methods to evaluate the 3D space
*without* having to embed in a 4D space to answer the same questions.

Secondly, you may be right that it's an infinite universe. That
doesn't pose a problem for the big bang at all. To see that, let's
consider an *infinite* line, and you are standing at a point on the
line marked E. Now you look along the line and you see a point 14
clicks away (marked F) and observe somehow that it is receding from
you at a rate of 2 clicks per year. And you look at another point G
that is 21 clicks away and observe that it is receding at a rate of 3
clicks per year. And you look at another point H that is 42 clicks
away and it is receding at 6 clicks per year, and so on. You will be
able to conclude a few important things from this exercise:
1. The line is expanding uniformly, which produces the behavior that
the recession rate is proportional to the distance. (That
proportionality is 7 clicks per year recession per click distance
away.)
2. This conclusion is the VERY same conclusion that someone on F would
arrive at. In fact, it is the very same conclusion that someone on G
or H, or any other point on this *infinite* line would arrive at.
3. Even though it's an *infinite* line, if you track back how long ago
each of the points F, G, H (and others) were on top of E, you come up
with the *same* answer: 7 years. The *infinite* line started from a
single point 7 years ago, if the expansion rate was constant.

Draw this, and ponder it a bit. It may surprise you off the top of
your head that an *infinite* space could be traced back to a single
point in any finite amount of time, but this exercise should not only
convince you it's possible, but also give you the very basics of the
thinking behind the big bang.

PD

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