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Did there exist time t = 0?



 
 
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  #1  
Old February 28th 10, 05:27 PM posted to sci.astro
Alan Mackenzie[_2_]
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Posts: 7
Default Did there exist time t = 0?

Hi, SA,

It's commonly asserted that the universe began at time t = 0 with the Big
Bang. Is there any evidence for this existence of time t = 0?

An alternative is that there exists time t for all t 0, but not t = 0
itself. In this model, time stretches back indefinitely, since it has no
boundary, and there is no Big Bang; just that the way we measure it, we
compress all t epsilon into a tiny tiny time, possibly artificially.

In this latter model, then, the universe has been expanding forever, and
the way the cosmos now looks, will carry on expanding forever.

--
Alan Mackenzie (Nuremberg, Germany).

  #2  
Old February 28th 10, 06:26 PM posted to sci.astro
dlzc
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Posts: 1,426
Default Did there exist time t = 0?

Dear Alan Mackenzie:

On Feb 28, 9:27*am, Alan Mackenzie wrote:
....
It's commonly asserted that the universe began
at time t = 0 with the Big Bang. *Is there any
evidence for this existence of time t = 0?


There is no evidence for time before about 270,000 years after the Big
Bang.

An alternative is that there exists time t for all
t 0, but not t = 0 itself.


There is no evidence for time prior to the Big Bang, since time is
just another coordinate in this Universe (depending on your
Cosmological model), and the Universe did not exist prior to the Big
Bang.

*In this model, time stretches back indefinitely,
since it has no boundary, and there is no Big
Bang; just that the way we measure it, we
compress all t epsilon into a tiny tiny time,
possibly artificially.


Unless it makes a quantifiable prediction that allows it to be
falsified, it is as useless as what we have now. Why do you waste
time positing another "model" that cannot be falsified?

In this latter model, then, the universe has
been expanding forever, and the way the cosmos
now looks, will carry on expanding forever.


Oh, so you do make a prediction that is easily falsified. Infinite
Universe has a "lack of iron and overabundance of hydrogen" problem.
Entropy has not been seen to reverse in a macroscopic scale in the 13+
billion years displayed. Yet stars continue to manufacture heavier
and heavier elements, use up their hydrogen "explode" and die. Where
is your iron?

David A. Smith
  #3  
Old February 28th 10, 07:30 PM posted to sci.astro
Alan Mackenzie[_2_]
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Posts: 7
Default Did there exist time t = 0?

dlzc wrote:
Dear Alan Mackenzie:


On Feb 28, 9:27?am, Alan Mackenzie wrote:
...
It's commonly asserted that the universe began
at time t = 0 with the Big Bang. ?Is there any
evidence for this existence of time t = 0?


There is no evidence for time before about 270,000 years after the Big
Bang.


Then there is no evidence for the Big Bang itself; a steadily expanding
universe fits the evidence just as well, does it not?

An alternative is that there exists time t for all t 0, but not t =
0 itself.


There is no evidence for time prior to the Big Bang, since time is just
another coordinate in this Universe (depending on your Cosmological
model), and the Universe did not exist prior to the Big Bang.


In this model, time stretches back indefinitely, since it has no
boundary, and there is no Big Bang; just that the way we measure it,
we compress all t epsilon into a tiny tiny time, possibly
artificially.


Unless it makes a quantifiable prediction that allows it to be
falsified, it is as useless as what we have now. Why do you waste time
positing another "model" that cannot be falsified?


I wasn't aware of that non-falsifiability, if indeed the idea is
non-falsifiable. I also want to make people think. There's something
physically abhorrent about an infinite energy density, which is surely
more abhorrent, more complicated, than time being topologically open.

In this latter model, then, the universe has been expanding forever,
and the way the cosmos now looks, will carry on expanding forever.


Oh, so you do make a prediction that is easily falsified. Infinite
Universe has a "lack of iron and overabundance of hydrogen" problem.
Entropy has not been seen to reverse in a macroscopic scale in the 13+
billion years displayed. Yet stars continue to manufacture heavier
and heavier elements, use up their hydrogen "explode" and die. Where
is your iron?


Sorry, I'm not well enough up on the subject to see how the first part of
your paragraph is related to the rest.

David A. Smith


--
Alan Mackenzie (Nuremberg, Germany).

  #4  
Old March 1st 10, 02:22 AM posted to sci.astro
dlzc
external usenet poster
 
Posts: 1,426
Default Did there exist time t = 0?

Dear Alan Mackenzie:

On Feb 28, 11:30*am, Alan Mackenzie wrote:
dlzc wrote:
Dear Alan Mackenzie:
On Feb 28, 9:27?am, Alan Mackenzie wrote:
...
It's commonly asserted that the universe began
at time t = 0 with the Big Bang. ?Is there any
evidence for this existence of time t = 0?

There is no evidence for time before about 270,000
years after the Big Bang.


Then there is no evidence for the Big Bang itself; a
steadily expanding universe fits the evidence just as
well, does it not?


No. There is no physics that is visible "this side" of the quench of
the CMBR medium, that would permit that. In fact, distant objects are
"anomalously" larger that today's, since they sourced their light into
a smaller Universe. Extrapolation back an additional 270,000 years,
based on the 13+ billion we have shown is a small step. "Infinite" is
a good bit further.

An alternative is that there exists time t for all
t 0, but not t = 0 itself.


There is no evidence for time prior to the Big Bang,
since time is just another coordinate in this Universe
(depending on your Cosmological model), and the
Universe did not exist prior to the Big Bang.


In this model, time stretches back indefinitely, since
it has no boundary, and there is no Big Bang; just
that the way we measure it, we compress all t
epsilon into a tiny tiny time, possibly artificially.


Unless it makes a quantifiable prediction that allows
it to be falsified, it is as useless as what we have
now. *Why do you waste time positing another
"model" that cannot be falsified?


I wasn't aware of that non-falsifiability, if indeed the
idea is non-falsifiable. *I also want to make people
think.


You cannot make them think of your own idea, when you've spent no
effort learning the billion or so cosmologies that are already out
there, some of which are "superficially" like your own.

*There's something physically abhorrent about an
infinite energy density, which is surely more abhorrent,
more complicated, than time being topologically open.


These are your personal choices. In a small Universe, there is as
much matter to the left as to the right. There is nothing to keep you
small...

Personally, I hold the CMBR to be the entire history of light that
entered the black hole that is our Universe, from our container
Universe. The horizon, if small enough, shreds all heavier elements
to protons, electrons and neutrons. But then we aren't discussing my
problem either...

In this latter model, then, the universe has been
expanding forever, and the way the cosmos now
looks, will carry on expanding forever.


Oh, so you do make a prediction that is easily
falsified. *Infinite Universe has a "lack of iron and
overabundance of hydrogen" problem. Entropy
has not been seen to reverse in a macroscopic
scale in the 13+ billion years displayed. *Yet
stars continue to manufacture heavier and heavier
elements, use up their hydrogen "explode" and die.
*Where is your iron?


Sorry, I'm not well enough up on the subject to see
how the first part of your paragraph is related to the rest.


Then how are you going to *make* people think, if you are not
interested enough in cosmology to know what else is out there?
http://www.astro.ucla.edu/~wright/cosmology_faq.html
http://www.astro.ucla.edu/~wright/cosmology_faq.html#RB
http://www.astro.ucla.edu/~wright/cosmo_03.htm

David A. Smith

David A. Smith
  #5  
Old March 1st 10, 02:26 AM posted to sci.astro
Androcles[_27_]
external usenet poster
 
Posts: 96
Default Did there exist time t = 0?


"dlzc" wrote in message
...
Dear Alan Mackenzie:

On Feb 28, 11:30 am, Alan Mackenzie wrote:
dlzc wrote:
Dear Alan Mackenzie:
On Feb 28, 9:27?am, Alan Mackenzie wrote:
...
It's commonly asserted that the universe began
at time t = 0 with the Big Bang. ?Is there any
evidence for this existence of time t = 0?

There is no evidence for time before about 270,000
years after the Big Bang.


Then there is no evidence for the Big Bang itself; a
steadily expanding universe fits the evidence just as
well, does it not?


No. There is no physics that is visible "this side" of the quench of
the CMBR medium, that would permit that. In fact, distant objects are
"anomalously" larger that today's, since they sourced their light into
a smaller Universe. Extrapolation back an additional 270,000 years,
based on the 13+ billion we have shown is a small step. "Infinite" is
a good bit further.

An alternative is that there exists time t for all
t 0, but not t = 0 itself.


There is no evidence for time prior to the Big Bang,
since time is just another coordinate in this Universe
(depending on your Cosmological model), and the
Universe did not exist prior to the Big Bang.


In this model, time stretches back indefinitely, since
it has no boundary, and there is no Big Bang; just
that the way we measure it, we compress all t
epsilon into a tiny tiny time, possibly artificially.


Unless it makes a quantifiable prediction that allows
it to be falsified, it is as useless as what we have
now. Why do you waste time positing another
"model" that cannot be falsified?


I wasn't aware of that non-falsifiability, if indeed the
idea is non-falsifiable. I also want to make people
think.


You cannot make them think of your own idea, when you've spent no
effort learning the billion or so cosmologies that are already out
there, some of which are "superficially" like your own.

There's something physically abhorrent about an
infinite energy density, which is surely more abhorrent,
more complicated, than time being topologically open.


These are your personal choices. In a small Universe, there is as
much matter to the left as to the right. There is nothing to keep you
small...

Personally, I hold the CMBR to be the entire history of light that
entered the black hole that is our Universe, from our container
Universe. The horizon, if small enough, shreds all heavier elements
to protons, electrons and neutrons. But then we aren't discussing my
problem either...

In this latter model, then, the universe has been
expanding forever, and the way the cosmos now
looks, will carry on expanding forever.


Oh, so you do make a prediction that is easily
falsified. Infinite Universe has a "lack of iron and
overabundance of hydrogen" problem. Entropy
has not been seen to reverse in a macroscopic
scale in the 13+ billion years displayed. Yet
stars continue to manufacture heavier and heavier
elements, use up their hydrogen "explode" and die.
Where is your iron?


Sorry, I'm not well enough up on the subject to see
how the first part of your paragraph is related to the rest.


Then how are you going to *make* people think, if you are not
interested enough in cosmology to know what else is out there?
http://www.astro.ucla.edu/~wright/cosmology_faq.html
http://www.astro.ucla.edu/~wright/cosmology_faq.html#RB
http://www.astro.ucla.edu/~wright/cosmo_03.htm

David A. Smith
Take it to religion.cosmo, Smiffy. This is sci.astro.
David A. Smith
Take it to religion.cosmo, Smiffy. This is sci.astro.

  #6  
Old March 1st 10, 05:43 AM posted to sci.astro
Yousuf Khan
external usenet poster
 
Posts: 594
Default Did there exist time t = 0?

Alan Mackenzie wrote:
Hi, SA,

It's commonly asserted that the universe began at time t = 0 with the Big
Bang. Is there any evidence for this existence of time t = 0?


The easy answer is that we don't have evidence to determine the
existence of time before the Big Bang. Similarly, we also don't have any
evidence for the existence of space before the BB either.


However, to get a little speculative, it's possible that the universe
existed before the BB, and that the universe was already infinite, long
before the BB. The universe may have existed as an infinite void, where
there was neither a direction of time nor a direction in space. Inside
the void, time neither flowed backwards or forwards, and events
(fluctuations) simply happened randomly. One such random event resulted
in the universe that we see now. Our universe is still part of the
infinite void, but it's moving in only one direction in the time
dimension. The void itself remains *on average* flowing neither forwards
or backwards, so that means that if our universe fluctuated out of it in
one direction of time, then that means some other universe was created
that has time flowing the opposite direction. The inhabitants of that
universe don't consider that their time is flowing backwards, then think
it's flowing forward.

Yousuf Khan
 




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