Dark Energy vs Fifth Force

[IM Egdall]

Saw interesting article on testing dark energy and general relativity versus the idea that there is a fifth force affecting gravity out there. Seems like Einstein wins, at least so far:

 

http://spaceandearthsciencearticles.blogspot.com/2012/05/is-there-fifth-force-that-alters.html?spref=tw

 

 

Comments?

[timo]

So astrophysicists performed a measurement fully compatible with mainstream physics that constrains the parameters of some not-further specified set of other models such that the extra parameters cannot have arbitrary values, anymore - unless the model is expanded by even more free parameters, of course .

 

My first thought is: Boring.

(but hey, that's just my personal first impression, and possibly due to not being familiar with the motivation for "5th force"-models in the first place)

[IM Egdall]

So astrophysicists performed a measurement fully compatible with mainstream physics that constrains the parameters of some not-further specified set of other models such that the extra parameters cannot have arbitrary values, anymore - unless the model is expanded by even more free parameters, of course .

 

My first thought is: Boring.

(but hey, that's just my personal first impression, and possibly due to not being familiar with the motivation for "5th force"-models in the first place)

 

Ya but no one knows what is causing the acceleration of the expansion of the universe. The most popular theory is the vacuum of space itself is somehow producing this outward push. And physicists model this mysterious "dark energy" by adding a cosmological constant to the right side of Einstein's field equations of general relativity.

 

Or maybe its Einstein's general relativity itself which is wrong at cosmic distances? Maybe there is some fifth force or other idea which accounts for the acceleration of the expansion.

 

I've heard these arguments for a number of years now. The link I gave is the first actual test I have come across which examines this question. And the test results tend to support general relativity. They point to this vacuum energy as the cause. I think this is a very big deal. And not at all boring.

Edited May 15, 2012 by IM Egdall

[space noob]

10 billion light years away? 3.7 billion years after the big bang, wouldn't we be looking at unevolved galaxies, it makes no sense to compare them to ours, or am I thinking wrong? Is this a new article? I feel like I've read this before,

Why can't the acceleration be like Christos Tsagas states, just an illusion, that way it would define that all forces would work the same way, still retaining dark flow and relativity would still be in affect, for this to be true I think all that needs to be changed is the existence of dark matter, don't we already know that dark matter isn't really there? i'm not too advanced in the Christos Tsagas area but it's still a possibility given my current knowledge of the universe but hey i'm no genius

Edited May 16, 2012 by space noob

[IM Egdall]

10 billion light years away? 3.7 billion years after the big bang, wouldn't we be looking at unevolved galaxies, it makes no sense to compare them to ours, or am I thinking wrong? Is this a new article? I feel like I've read this before,

Why can't the acceleration be like Christos Tsagas states, just an illusion, that way it would define that all forces would work the same way, still retaining dark flow and relativity would still be in affect, for this to be true I think all that needs to be changed is the existence of dark matter, don't we already know that dark matter isn't really there? i'm not too advanced in the Christos Tsagas area but it's still a possibility given my current knowledge of the universe but hey i'm no genius

 

Dark flow? Your words sent me on a google search. I found an article on testing with supernovas that seems to say this dark flow theory isn't right.

 

http://arstechnica.c...k-flow-mystery/

 

So I think dark matter and dark energy are still the favored theories of current mainstream physics.

 

Comments?

Edited May 16, 2012 by IM Egdall

[space noob]

I don't know whether i'm talking about dark flow or dark fluid

Dark fluid merits a wiki post

http://en.m.wikipedia.org/wiki/Dark_flow#section_2

Two groups have been constantly arguing over it's existence but it says that even in 2012 it can't be proven or unproven until we have further technology,

Your link may be from a side that is against dark flow,

Either way anyone could be right about it

What I was referring to was the way that dark matter affects the movements of galaxies,

I'm not stating dark matter isn't real i'm thinking if the only way we know it exists is due to gravity then is that really enough, there's still debate about dark matter

http://m.phys.org/news/2012-04-dark-theories-mysterious-lack-sun.html

http://science.slashdot.org/story/12/04/20/195215/survey-finds-no-hint-of-dark-matter-near-solar-system

Edited May 16, 2012 by space noob