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Old Sep 24th 2013, 03:41 PM   #1
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Where is the constant?

http://www.nobelprize.org/nobel_priz...sprize2011.pdf

Here the universes expansion is described as first slowing and then accelerating. My question is how does this jive with the Friedmann-Robertson-Walker solution?

http://www.modernrelativitysite.com/chap8.htm

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Old Sep 26th 2013, 11:27 AM   #2
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Inconstant

I had a quick glance at the sites you gave links for,
but frankly I'm too lazy to really give them the attention they deserve.

However, I noted that there was a brief phrase in http://www.modernrelativitysite.com/chap8.htm
which indicates that different assumptions for the cosmological constant give rise to different space time curvatures and thus expansion (or even contraction) rates for the universe.

Since no-one has any real clue what causes the dark-energy that they postulate gives rise to the cosmological constant, theorists are free to speculate that it can change, and thus the expansion rate can change.

In other words, I guess that they are saying the cosmological constant is not constant.

Last edited by MBW; Sep 26th 2013 at 11:28 AM. Reason: spelling
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Old Sep 26th 2013, 07:04 PM   #3
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Originally Posted by MBW View Post
In other words, I guess that they are saying the cosmological constant is not constant.
Yes, I've had the same thought for a long time. Any model of the Universe that incorporates inflation and dark energy would seem to have to have a cosmological "constant" that is changing. As the GR field equations can only be written using an extra constant we cannot have a time (or otherwise) varying cosmological constant.

Probably means that GR needs some tweaking....

-Dan
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Old Oct 7th 2013, 08:14 AM   #4
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I do have an inkling of what dark energy is...
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Old Oct 7th 2013, 11:02 AM   #5
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Talking My Inkling (apologies to Chuck Berry)

Many people have an inkling,
the trouble is they all have a different inkling...

However, you go for it!
someone somewhere is going to crack this one day
and who knows ...
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Old Oct 7th 2013, 12:59 PM   #6
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I would like to propose a primary entity that is toroidal and expanding. At a single point this entity compresses time/space infinitely, at an infinite distance time/space is expanded infinitely, and in between the relationship between time and space is exponential. The interference pattern between such entities is what we perceive as matter. Comments welcome and math desired!
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Old Oct 7th 2013, 05:02 PM   #7
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Originally Posted by Troll View Post
I would like to propose a primary entity that is toroidal and expanding. At a single point this entity compresses time/space infinitely, at an infinite distance time/space is expanded infinitely, and in between the relationship between time and space is exponential. The interference pattern between such entities is what we perceive as matter. Comments welcome and math desired!
(shrugs) Okay, I'll bite. What is your "primary entity?" Are you thinking particle, space-time "material," or something else? The way you describe it makes me think of a shock wave more than anything else.

A toroid is a basically what you get when you take a cylinder and bend it so that the end points meet. Are you saying that the Universe exists inside the volume of the toroid? But if you have more than one of these what happens? Can your toroid expand inside another? I'm really not understanding the basic geometry here.

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Old Oct 7th 2013, 05:16 PM   #8
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Originally Posted by topsquark View Post
(shrugs) Okay, I'll bite. What is your "primary entity?" Are you thinking particle, space-time "material," or something else? The way you describe it makes me think of a shock wave more than anything else.

A toroid is a basically what you get when you take a cylinder and bend it so that the end points meet. Are you saying that the Universe exists inside the volume of the toroid? But if you have more than one of these what happens? Can your toroid expand inside another? I'm really not understanding the basic geometry here.

-Dan
I am proposing primary entities that compose our universe, are responsible for all that is the universe.

They are pouring energy into our universe at an accelerating rate and pushing the expansion. The spacing and distribution in an infinite universe is meaningless, however in our finite universe they can be defined. I could be talking the higgs... not sure... could use some math. They must be toroidal because they must have polarity. There are a great number of "must be's" for example the relationship of orientation could produce the perceived "colors" of the higgs particle. Interference between them could be what we perceive as particles. Light could be waves traveling through them which would explain light as a wave and a massless particle... I could go on and on and on... My point is I think it is time we quit limiting ourselves.
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Old Oct 7th 2013, 07:19 PM   #9
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Originally Posted by Troll View Post
I am proposing primary entities that compose our universe, are responsible for all that is the universe.
Yes, but what are they? But I'll leave my other comments in the new thread you posted.

Originally Posted by Troll View Post
example the relationship of orientation could produce the perceived "colors" of the higgs particle.
The Higgs is colorless. If it weren't then we wouldn't be able to detect it.

Originally Posted by Troll View Post
Interference between them could be what we perceive as particles. Light could be waves traveling through them which would explain light as a wave and a massless particle
Wave-particle duality is a well known and on occasion a very frustrating problem for experimentalists. If you do an experiment to detect waves you detect waves, if you are looking for particles you find particles. One of the difficulties here is that quantum "particles" are neither particles, nor waves. We really don't know what they are. I like whoever coined the term "wavicles." There is no way to separate this...quantum particles are not like anything seen in the macroscopic world and trying to define them in any other way is fruitless.

-Dan
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Old Oct 9th 2013, 10:38 AM   #10
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I don't yet have the mathematical wherewithal to understand that... but what I think it is is this:
First, acceleration - due to both leftover from the inflationary period and the dark energy - slows down because the positive gravity is stronger at that range than the dark energy's negative gravity.

But at a certain distance, because dark energy is constant everywhere, but matter isn't, the dark energy's negative gravity becomes more than the positive gravity. And then it starts to accelerate again after passing this threshold.
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