Our Expanding Universe

I have always wanted an answer that I can understand to the following question.

Simply asked, "What is our Universe expannning into"?

Please explain it assuming I am an *ordinary* 13 years old.

I finally found this question and its answer, in a FAQ called
"Frequently Asked Questions in Cosmology":

http://www.astro.ucla.edu/~wright/cosmology_faq.html

It is all "%^$@^$%@^" to me. :-(

Thanks in advance to "anyone/everyone" who can explain it to
me so that I understand.

BluMax

Dear BluMax:

"BluMax" wrote in message
news:2004112913055116807%alsimcoe@alsimcoecom...
I have always wanted an answer that I can understand to the following
question.

Simply asked, "What is our Universe expannning into"?

Please explain it assuming I am an *ordinary* 13 years old.

I finally found this question and its answer, in a FAQ called
"Frequently Asked Questions in Cosmology":

http://www.astro.ucla.edu/~wright/cosmology_faq.html

It is all "%^$@^$%@^" to me. :-(

Thanks in advance to "anyone/everyone" who can explain it to
me so that I understand.

Look at a cell in a spreadsheet. Put in a value of 1. Increment the value
by 1. Allow iteration, and have the formula self-increment. What is the
cell "expanding into"?

Spacetime is similar to a giant spreadsheet that quantum mechanics plays
out on. We're just trying to figure out the formulas that populate it.

David A. Smith

"BluMax" wrote in message
news:2004112913055116807%alsimcoe@alsimcoecom...
I have always wanted an answer that I can understand to the following
question.

Simply asked, "What is our Universe expannning into"?

Please explain it assuming I am an *ordinary* 13 years old.

I finally found this question and its answer, in a FAQ called
"Frequently Asked Questions in Cosmology":

http://www.astro.ucla.edu/~wright/cosmology_faq.html

It is all "%^$@^$%@^" to me. :-(

Thanks in advance to "anyone/everyone" who can explain it to
me so that I understand.

BluMax

Hi BluMax,

It's hard to get your head around this, because we tend to think of
things in terms we already understand and changing our understanding
involves thinking in the abstract.

The best way I can get to understand it is to think in the *wrong* way,
and then work out how to change the way I'm thinking to get the *right*
mental image.

First the *wrong* way . . .
Think of it as if we took a movie of a firework going off at the in the
middle of a large room like a school hall. The space is filled with
sparkles and streamers. As the movie plays, fast moving objects are
quicker to get to the walls while the slower ones are nearer the centre.
In this case, as time progresses, the explosion moves into the empty
space of the concert hall. This empty space is already there, and we
see the fastest moving sparks fill this space.
But that is the *wrong* way to view it.

Now let's modify this to get closer to the *right* idea.
To change the mental image in your head, imagine that you are looking at
the movie frame where the firework has just filled the hall - everywhere
is filled with something. Now mentally play the movie backwards, but
imagine that the walls of the hall itself are moving back with the
firework. Instead of the explosion getting smaller inside the hall; the
whole hall and explosion are getting smaller at the same time. Mentally
play the movie forwards and backwards in your head seeing how the whole
thing is expanding/contracting as a single item. There is no need to
think about what the universe is expanding 'into', because there is
nothing 'outside' - the whole universe is 'inside' the model, it's just
getting bigger all the time.

It's not a complete answer, and it's not perfect, but I hope you can see
how the two mental images differ. Don't expect to understand it straight
away, but keep plugging away with it .

Hope this helps.

BluMax wrote:

I have always wanted an answer that I can understand to the following
question.

Simply asked, "What is our Universe expannning into"?

Please explain it assuming I am an *ordinary* 13 years old.

I finally found this question and its answer, in a FAQ called
"Frequently Asked Questions in Cosmology":

http://www.astro.ucla.edu/~wright/cosmology_faq.html

It is all "%^$@^$%@^" to me. :-(

Thanks in advance to "anyone/everyone" who can explain it to
me so that I understand.

BluMax

Hi BluMax
Objects in space, in our normal space, grow by taking
*more space*.

But for Space itself to do that, Space must take more of
Space, and in order to do that, Space must be larger than it is.

Hence, the notion of space expansion is self-contradictory
and can't exist. There can be no expansion of Space itself,
only of an object in Space.

Your intuition is 100% right BluMax, do not let the talk lead you
astray.

Furthermore, there is no such thing as the Universe. The
Universe denotes no special object; in fact, it denotes no
object of any kind. The fact that all things have a cause does
not mean that the Universe has a cause any more than the
fact that all men have a mother means that Humanity has a
mother. Hence the Universe does not have a cause. The
Universe does not have an age.

The universe is a short hand, comprehensive reference
to all things that exist.

And things being many, they have many ages . Hence, there is no
such thing as the age of the universe, unless we mean an
....average age. The Universe is just an inventory word, an
inventory meant to be exhaustive. And inventories have no
size. (I guess.) Hence, the universe has no size either.

References:

Apeiron, Vol 10 Nr 1, January 2003
"A Bang into Nowhere"
Constantin Antonopoulos
National Technical University of Athens

OG wrote:
[snip]
Now let's modify this to get closer to the *right* idea.
To change the mental image in your head, imagine that you are looking at
the movie frame where the firework has just filled the hall - everywhere
is filled with something. Now mentally play the movie backwards, but
imagine that the walls of the hall itself are moving back with the
firework. Instead of the explosion getting smaller inside the hall; the
whole hall and explosion are getting smaller at the same time.

Then, the hall is shrinking *IN SPACE*. The concept of expansion
(or its opposite contraction) are irrevocably tied to the concept
of SPACE. There is *NO WAY OUT* of this contradiction.

Mentally
play the movie forwards and backwards in your head seeing how the whole
thing is expanding/contracting as a single item. There is no need to
think about what the universe is expanding 'into', because there is
nothing 'outside' - the whole universe is 'inside' the model, it's just
getting bigger all the time.

There is no sense to something getting "bigger" if there is
no concept of an empty space where this thing is getting bigger into!

The intuition of BluMax is 100% right!

It's not a complete answer, and it's not perfect, but I hope you can see
how the two mental images differ. Don't expect to understand it straight
away, but keep plugging away with it .

Hope this helps.




It doesn't.

"jacob navia" wrote in message
...
OG wrote:
[snip]
Now let's modify this to get closer to the *right* idea.
To change the mental image in your head, imagine that you are
looking at
the movie frame where the firework has just filled the hall -
everywhere
is filled with something. Now mentally play the movie backwards, but
imagine that the walls of the hall itself are moving back with the
firework. Instead of the explosion getting smaller inside the hall;
the
whole hall and explosion are getting smaller at the same time.

Then, the hall is shrinking *IN SPACE*. The concept of expansion
(or its opposite contraction) are irrevocably tied to the concept
of SPACE. There is *NO WAY OUT* of this contradiction.

I'm sure it doesn't really matter if you don't get a feel for it.

Mentally
play the movie forwards and backwards in your head seeing how the
whole
thing is expanding/contracting as a single item. There is no need to
think about what the universe is expanding 'into', because there is
nothing 'outside' - the whole universe is 'inside' the model, it's
just
getting bigger all the time.

There is no sense to something getting "bigger" if there is
no concept of an empty space where this thing is getting bigger into!

It's not the end of the world if you don't get it.

The intuition of BluMax is 100% right!

It's not a complete answer, and it's not perfect, but I hope you can
see
how the two mental images differ. Don't expect to understand it
straight
away, but keep plugging away with it .

Hope this helps.




It doesn't.

OG wrote:

"jacob navia" wrote in message
...

OG wrote:
[snip]

Now let's modify this to get closer to the *right* idea.
To change the mental image in your head, imagine that you are

looking at

the movie frame where the firework has just filled the hall -

everywhere

is filled with something. Now mentally play the movie backwards, but
imagine that the walls of the hall itself are moving back with the
firework. Instead of the explosion getting smaller inside the hall;

the

whole hall and explosion are getting smaller at the same time.

Then, the hall is shrinking *IN SPACE*. The concept of expansion
(or its opposite contraction) are irrevocably tied to the concept
of SPACE. There is *NO WAY OUT* of this contradiction.


I'm sure it doesn't really matter if you don't get a feel for it.


"But the Emperor has nothing on! said a little child.
And one person whispered to the other what the child
had said. "He has nothing on -- a child says he has nothing
on!

"But he has nothing on!" cried all the people. The Emperor
writhed, for he knew it was all true. But he thought "the
procession must go on now". So he held himself stiffer than
ever, and the chamberlains held up the invisible train.


H.C. Andersen. The Emperor's new clothes.

On 2004-11-30 11:24:50 -0500, jacob navia said:

BluMax wrote:

I have always wanted an answer that I can understand to the following question.

Simply asked, "What is our Universe expannning into"?

Please explain it assuming I am an *ordinary* 13 years old.

I finally found this question and its answer, in a FAQ called
"Frequently Asked Questions in Cosmology":

http://www.astro.ucla.edu/~wright/cosmology_faq.html

It is all "%^$@^$%@^" to me. :-(

Thanks in advance to "anyone/everyone" who can explain it to
me so that I understand.

BluMax

Hi BluMax
Objects in space, in our normal space, grow by taking
*more space*.

But for Space itself to do that, Space must take more of
Space, and in order to do that, Space must be larger than it is.

Hence, the notion of space expansion is self-contradictory
and can't exist. There can be no expansion of Space itself,
only of an object in Space.

Your intuition is 100% right BluMax, do not let the talk lead you
astray.

Furthermore, there is no such thing as the Universe. The
Universe denotes no special object; in fact, it denotes no
object of any kind. The fact that all things have a cause does
not mean that the Universe has a cause any more than the
fact that all men have a mother means that Humanity has a
mother. Hence the Universe does not have a cause. The
Universe does not have an age.

The universe is a short hand, comprehensive reference
to all things that exist.

And things being many, they have many ages . Hence, there is no
such thing as the age of the universe, unless we mean an
...average age. The Universe is just an inventory word, an
inventory meant to be exhaustive. And inventories have no
size. (I guess.) Hence, the universe has no size either.

References:

Apeiron, Vol 10 Nr 1, January 2003
"A Bang into Nowhere"
Constantin Antonopoulos
National Technical University of Athens

Wow, hmmm..... maybe now I might be *Starting" to understand.

So, if I understand correctly, the volume (so to speak) of space is
already there
and the Universe is merely expanding into it.

Right?

Do I also extrapulate from your answer then, that the volume of Space
would be endless (to infinity) ?

BluMax

jacob navia wrote:
OG wrote:
[snip]

Now let's modify this to get closer to the *right* idea.
To change the mental image in your head, imagine that you are looking at
the movie frame where the firework has just filled the hall - everywhere
is filled with something. Now mentally play the movie backwards, but
imagine that the walls of the hall itself are moving back with the
firework. Instead of the explosion getting smaller inside the hall; the
whole hall and explosion are getting smaller at the same time.


Then, the hall is shrinking *IN SPACE*. The concept of expansion
(or its opposite contraction) are irrevocably tied to the concept
of SPACE. There is *NO WAY OUT* of this contradiction.

Yes, there is. Simply replace "the universe is getting bigger"
(essentially an external view) with "the distance between
any two points in the universe is increasing" (an internal view).
The latter works also for a universe with infinite volume.


Mentally
play the movie forwards and backwards in your head seeing how the whole
thing is expanding/contracting as a single item. There is no need to
think about what the universe is expanding 'into', because there is
nothing 'outside' - the whole universe is 'inside' the model, it's just
getting bigger all the time.


There is no sense to something getting "bigger" if there is
no concept of an empty space where this thing is getting bigger into!

Well, then don't say that the universe is getting bigger - which
anyway makes no sense if its volume is infinite.


The intuition of BluMax is 100% right!

No. Like you, he is simply approaching the problem from the wrong
point of view.



[snip]

Bye,
Bjoern

jacob navia wrote:
BluMax wrote:

I have always wanted an answer that I can understand to the following
question.

Simply asked, "What is our Universe expannning into"?

Please explain it assuming I am an *ordinary* 13 years old.

I finally found this question and its answer, in a FAQ called
"Frequently Asked Questions in Cosmology":

http://www.astro.ucla.edu/~wright/cosmology_faq.html

It is all "%^$@^$%@^" to me. :-(

Thanks in advance to "anyone/everyone" who can explain it to
me so that I understand.

BluMax

Hi BluMax
Objects in space, in our normal space, grow by taking
*more space*.

Wrong. They do not grow *by* taking more space. It's the
other way round: *because* they grow, they occupy more space.


But for Space itself to do that, Space must take more of
Space, and in order to do that, Space must be larger than it is.

Non sequitur. Why should space behave in the same way as objects
in space?



Hence, the notion of space expansion is self-contradictory
and can't exist.

No, it isn't. Perhaps you should look at the actual equations
of GR and the math behind it (Riemannian geometry) instead of
relying on poor analogies, don't you think?


There can be no expansion of Space itself,
only of an object in Space.

Starting with a false premise, you can arrive at any conclusion
you like...



Your intuition is 100% right BluMax, do not let the talk lead you
astray.

Intuition is very often misleading in physics. My intuition tells
me also that the sun goes around the earth, that heavy things fall
faster than light ones, and that when I shoot particles at two
slits, they will go only through one of them.


Furthermore, there is no such thing as the Universe.

Ouch.


The Universe denotes no special object; in fact, it denotes no
object of any kind.

Beside "everything there is", you mean?


The fact that all things have a cause

Even that is not right. What is the cause of the decay of
an unstable particle? (please note that "its instability" is
not in any way a sufficient answer)


does not mean that the Universe has a cause any more than the
fact that all men have a mother means that Humanity has a
mother. Hence the Universe does not have a cause.

Non sequitur. The only logical conclusion you can draw is
"the universe does not need to have a cause". It does *not*
follow that the universe indeed has no cause.


The Universe does not have an age.

And that follows even less.


The universe is a short hand, comprehensive reference
to all things that exist.

Just above you said "there is no such thing as the Universe".
So you want to said that "there is no such thing as 'all things
that exist'"? Interesting statement.

Or do you want to quibble now that in one case, you wrote "Universe" and
in the other only "universe"?


And things being many, they have many ages. Hence, there is no
such thing as the age of the universe,

This is sophistry. And rather bad sophistry even.


unless we mean an
...average age. The Universe is just an inventory word, an
inventory meant to be exhaustive. And inventories have no
size. (I guess.)

You mean that we can't assign a size to the collection of
"all things which exist"? Why not?


Hence, the universe has no size either.

Again, starting from a false premise...



References:

Apeiron, Vol 10 Nr 1, January 2003
"A Bang into Nowhere"
Constantin Antonopoulos
National Technical University of Athens

Does Antonopoulos also use such strange arguments as the one
you presented above?


Bye,
Bjoern