Dark Energy vs. String Theory

[killer900]

ok, i read that there is a "leakage" of gravity out of the universe, and so do you think that it is "Dark Energy", or do the gravitons in String Theory cause it?

Dark Energy: it is estimated that 70% of the universe is dark energy, and it is the complete oppisite of gravity, and this is why gravity is weaker

String Theory: Since "gravitons" are not connected to our 3 deminsions (there are 11 deminsions in string theory) they can pass through all the deminsions. and right now there is not a high concentration of these "gravitons" in our 3 deminsions.

NOTE: the gravity leakage is only apparent on huge scales (like the whole universe)

Sources:
Scientific American
Dark Energy
String Theory

 

[MacMan]

Dark energy isn't a theory, it's a conjecture, stuff they haven’t found yet but are pretty sure exists. There's nothing between the two that contradict each other, dark energy itself does not explain gravity, that is more on the string theory side.

 

[killer900]

not really, i hope you read all the sites.... anyways, if String Theory is true, then there is no need for Dark Energy, for we would be able to explain the leakage of gravity by the gravitons moving through our 3 deminsions but not staying in any of our deminsions... and they are not "pretty sure" it exists, but it be a great thing if string theory turns out to be true.

 

[MacMan]

What you're saying sounds like a really user-friendly version of everything I've read before, but I've never heard gravity described by "leaks" or whatever, I've only known is as a force on particles. Gravitons, along with every other sub particle, exist in a world with 11 dimensions, so do we. The Grassman dimensions are so small though, I've never heard of anything on the matter of particles "staying" in them, they're almost nonexistent. I don't see how if one is true then the other isn't, dark energy (which I thought was energy in the form of matter, I always confuse it with dark matter) is just another something to add to the collection of quantum particles and forces, string theory is not going to collapse if they find something new.
There are also images on NASA's cosmology site of gravity around stars, with suspected dark energy circled in red, look around, maybe I'll take the time to find them.

 

[killer900]

ok, you ought to read "The Elegant Universe" by Brian Greene, excellent book, explains everything. I'm getting "The Fabric of The Cosmos" by him to, seems cool to. (I know i'm so geeky...)

o, and read that "scientific american" it's the one about gravity "leakage" and come on people REPLY!!!

 

[MacMan]

I've read Elegant Universe and many other books on the subject. That Scientific American article says nothing about gravity "leaks."

 

[killer900]

hmmm, well heres a site: Variable Strength of Gravity

it basically states that if string theory is true that we should expect that gravity will kinda go up and down in strength, because of "gravitons" going in and out of our 3 deminsions.