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It seems that as Dark Energy increases, Dark Matter decreases astime goes on



 
 
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  #21  
Old December 27th 12, 10:29 PM posted to sci.astro
Yousuf Khan[_2_]
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Posts: 1,686
Default It seems that as Dark Energy increases, Dark Matter decreasesastime goes on

On 24/12/2012 10:07 AM, dlzc wrote:
Dear Yousuf Khan:

On Monday, December 24, 2012 1:24:25 AM UTC-7, Yousuf Khan wrote:
On 18/12/2012 11:21 AM, dlzc wrote:

On Monday, December 17, 2012 6:07:45 PM UTC-7, Yousuf Khan
wrote:
On 19/11/2012 3:09 PM, dlzc wrote:


OK, but this is not required, is not detectable in the
laboratory, and violates the laws of physics not changing
over time.


I doubt that this law has been absolutely proven.


Nothing is Science can be.


It may hold true within our current era, but that's just a
localized phenomenon.


Fine structure constant does not change as much as 1 part in 10^8
over the displayed history of the Universe, and the observations
you have drawn your conclusions on *assume* no change in physics
over that time.


It's hard to tell what the laws of physics were like during the
Inflationary Big Bang period. We can only see as far back as the
CMBR,


The observation that started this post was clearly this side of the
CMBR. And the observation *assumed* the laws of physics did not
change over that time, to reach their conclusions.


Yes, it may have started about post-CMBR universe, but quite obviously
it's quite clear we're now discussing pre-CMBR too.

i.e. 300k years after the BB, which would already be too late after
the Inflationary period. By the time of the CMBR, the Universe had
already settled into its current stable state. The Fine Structure
Constant was pretty much already at the current level, give or take
a few parts per whatever. However, during Inflation that FSC might
have been quite wildly different.


Sure. And the CMBR might be what our container Universe looks like,
and there was no Big Bang.


When you say, "no Big Bang" are you talking about a constantly
Inflationary universe without Big Bang, or are you talking about good
old Static universe?

Gravity is often thought of as negative energy.


Incorrectly so, since it is energy-neutral.


No idea where you get that.


Gravity just changes "energy of position" to "energy of motion", net
energy does not change, until friction kicks in.


Never knew that standing still had any energy at all. As Newton said,
"things at rest, remain at rest; things in motion, remain at that same
motion." No energy needed for those.

If it was not already matter, no push was required.


The matter would've had to come later, after Inflation ended.
That which is being "pushed", is space itself.


Which arises from matter / energy, and cannot exist without it.
Which is why it plays such a strong role in the curvature of
spacetime.


Or more likely matter-energy requires space-time, and cannot exist
without it. I don't even think this is just another classic
chicken/egg problem,


I agree here, however...

I think it's quite plainly obvious that energy condenses out of
spacetime, and that matter condenses out of energy. I think
spacetime is the basic building block, and energy and then matter
come out of that.


Time evolves from the 2nd law of thermodynamics, and space evolves
from conservation of momentum and multiple bodies. So to me it is
most likely that they all cooked out *precisely* together.


The laws of thermodynamics is probably a macroscopic end-effect of the
laws of quantum mechanics. Time's direction likely is another end-effect.

As for space being just whatever is between two objects, is a bit
old-fashioned. It's quite clearly an object in and of itself these days.

Yousuf Khan
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  #22  
Old December 28th 12, 02:00 AM posted to sci.astro
dlzc
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Posts: 1,426
Default It seems that as Dark Energy increases, Dark Matter decreasesastime goes on

Dear Yousuf Khan:

On Thursday, December 27, 2012 2:29:23 PM UTC-7, Yousuf Khan wrote:
On 24/12/2012 10:07 AM, dlzc wrote:
On Monday, December 24, 2012 1:24:25 AM UTC-7, Yousuf Khan wrote:
On 18/12/2012 11:21 AM, dlzc wrote:

....
Fine structure constant does not change as
much as 1 part in 10^8 over the displayed
history of the Universe, and the observations
you have drawn your conclusions on *assume*
no change in physics over that time.


It's hard to tell what the laws of physics
were like during the Inflationary Big Bang
period. We can only see as far back as the
CMBR,


The observation that started this post was
clearly this side of the CMBR. And the
observation *assumed* the laws of physics
did not change over that time, to reach
their conclusions.


Yes, it may have started about post-CMBR
universe, but quite obviously it's quite
clear we're now discussing pre-CMBR too.


Not based on this observation, this finding, this original post.

i.e. 300k years after the BB, which would
already be too late after the Inflationary
period. By the time of the CMBR, the
Universe had already settled into its
current stable state. The Fine Structure
Constant was pretty much already at the
current level, give or take a few parts per
whatever. However, during Inflation that
FSC might have been quite wildly different.


Sure. And the CMBR might be what our container
Universe looks like, and there was no Big Bang.

When you say, "no Big Bang" are you talking
about a constantly Inflationary universe
without Big Bang, or are you talking about good
old Static universe?


http://math.ucr.edu/home/baez/gr/oz1.html
.... if behind our event horizon is an identical Universe, then "beyond" the CMBR, is the Universe that contains ours. Just another option, still outside the realm of this discussion.


Gravity is often thought of as negative energy.


Incorrectly so, since it is energy-neutral.


No idea where you get that.


Gravity just changes "energy of position" to
"energy of motion", net energy does not change,
until friction kicks in.


Never knew that standing still had any energy
at all.


Water behind a dam has no energy? A pendulum at the top of its swings, has no energy?

As Newton said, "things at rest, remain at rest;
things in motion, remain at that same motion."
No energy needed for those.


Missing the examples above, aren't we?

....
Which arises from matter / energy, and
cannot exist without it. Which is why it
plays such a strong role in the curvature
of spacetime.


Or more likely matter-energy requires
space-time, and cannot exist without it. I
don't even think this is just another classic
chicken/egg problem,


I agree here, however...


I think it's quite plainly obvious that
energy condenses out of spacetime, and that
matter condenses out of energy. I think
spacetime is the basic building block, and
energy and then matter come out of that.


Time evolves from the 2nd law of
thermodynamics, and space evolves from
conservation of momentum and multiple bodies.
So to me it is most likely that they all
cooked out *precisely* together.


The laws of thermodynamics is probably a
macroscopic end-effect of the laws of
quantum mechanics.


Nope. Quantum mechanics does not "predict" either the 2nd law, nor time.

Time's direction likely is another end-effect.


I find no convincing evidence.

As for space being just whatever is between two
objects, is a bit old-fashioned. It's quite
clearly an object in and of itself these days.


I find no convincing evidence.

David A. Smith
  #23  
Old January 2nd 13, 10:28 PM posted to sci.astro
Steve Willner
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Posts: 1,169
Default It seems that as Dark Energy increases, Dark Matter decreases as time goes on

In article ,
Yousuf Khan writes:
Isn't it true that the reasons for the CMB spectrum are complete
guesswork?


No, I wouldn't say that's true. Given a model, the expected CMB
spectrum can be calculated. Most models disagree with observations.

The Mixed Dark Matter model fit the CMB just as
well as Lambda-CDM did, and it still does,


Reference, please? I'd be astonished if mixed dark matter fits the
WMAP spectrum. (The key is that neutrinos don't cluster the same way
dark matter does.)

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
  #24  
Old January 3rd 13, 12:00 AM posted to sci.astro
Steve Willner
external usenet poster
 
Posts: 1,169
Default It seems that as Dark Energy increases, Dark Matter decreases as time goes on

In article , I wrote:
I'd be astonished if mixed dark matter fits the
WMAP spectrum. (The key is that neutrinos don't cluster the same way
dark matter does.)


Maybe I should be prepared to be astonished; apparently some models
in this class are still considered worth discussing. At least a
quick search turned up one paper discussing them:
D. Anderhalden et al. JCAP 10, 047 (2012).
I didn't see anything about comparisons with WMAP data, though.

One thing obvious even to a non-expert like me is that such models
introduce two new free parameters: the mass of the putative warm
particles and the fraction of the overall dark matter they
constitute. That makes mixed models unattractive unless data show a
clear need for the extra component.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
 




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