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From: Infinity on 5 Jan 2010 15:19
Suppose you are told that the linear size of everything in the univers
has been doubled overnight.

1. Can you test this statement by measuring the sizes with a metre
stick?

2. Can you test it by using the fact that the speed of light is a
universal constant and has not changed?

3. What will happen if all the clocks in the universe also start
running at half the speed?
From: Sam Wormley on 5 Jan 2010 15:29
On 1/5/10 2:19 PM, Infinity wrote:
> Suppose you are told that the linear size of everything in the univers
> has been doubled overnight.
>

Dimensions don't have "fixed lengths"...

Do you mean to ask what would happen if distances between any two
arbitrary points increased by a factory of two? And ct increased
by a factor of two? Can't happen.

From: Infinity on 5 Jan 2010 23:40
On Jan 6, 1:29 am, Sam Wormley <sworml...(a)gmail.com> wrote:
> On 1/5/10 2:19 PM, Infinity wrote:
>
> > Suppose you are told that the linear size of everything in the univers
> > has been doubled overnight.
>
>    Dimensions don't have "fixed lengths"...
>
>    Do you mean to ask what would happen if distances between any two
>    arbitrary points increased by a factory of two? And ct increased
>    by a factor of two? Can't happen.

Yes, what if distances between any two arbitrary points increased by a
factor of two? Why can't ct increase by a factor of two?
From: Benj on 6 Jan 2010 03:14
On Jan 5, 3:29 pm, Sam Wormley <sworml...(a)gmail.com> wrote:

>    Do you mean to ask what would happen if distances between any two
>    arbitrary points increased by a factory of two? And ct increased
>    by a factor of two? Can't happen.

Obviously Sam, since this is a "thought experiment", your botware
brain is at a distinct disadvantage to the rest of us here. What
"can't happen" is for you to have a logical thought.
From: Benj on 6 Jan 2010 03:29
On Jan 5, 3:19 pm, Infinity <countableinfin...(a)gmail.com> wrote:
> Suppose you are told that the linear size of everything in the univers
> has been doubled overnight.
>
> 1. Can you test this statement by measuring the sizes with a metre
> stick?
>
> 2. Can you test it by using the fact that the speed of light is a
> universal constant and has not changed?
>
> 3. What will happen if all the clocks in the universe also start
> running at half the speed?

This is an old thought experiment that has long ago been answered.

1. The answer to this is no. since the size of your reference
increases to match the objects measured.

2. So what if instead of a meter stick we use the current standard of
so many wavelengths of a certain color light? Well That should
probably give no clue either although now we are getting into the
details of exactly HOW and what it means that dimensions have
"increased". We do pretty much have to assume that as matter stretches
that the wavelengths alongside it also stretch keeping the number of
wavelengths per meter the same number.

So then, can one tell if dimensions suddenly doubled on all objects
overnight? The physicist with whom I discussed this question told me
the answer is simple. The way you tell if all dimensions have secretly
doubled is that all the sausages in the meat store would fall down!
Think about why that would be! Good luck!

3. Now the question of time is a different dimension from space. And
you need to separate two ideas here. One is that all CLOCKS run
slower. The other is that TIME actually is slowed. Of course you'd
have to know what these things actually mean. But one can easily show
that some clocks (say crude electromagnetic clocks) actually do change
speed when observed in relative motion. SOME but not ALL such clocks
change with the well known Einsteinian time dilation. Some such clocks
even have the time shift depend on orientation. So an examination of
CLOCKS is an interesting exercise that can be enlightening. But a
shift in TIME would need be something quite different. If actual time
perception sped up or slowed down, how would you know? The question
would be "is there a sausage test" for time shifts? Who knows.

All interesting and good questions but it's highly doubtful you'll get
any meaningful or sensible answers from any of the regulars here.
Sam, for example, doesn't even understand the question!
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