String Theory, Dark Matter And Dark Energy

[ggolu2]

Can string theory explain dark matter and dark energy?

 

[jedishrfu]

There is a short discussion within the wiki article about String Theory and Dark Energy:

http://en.wikipedia.org/wiki/Dark_energy

Some theorists think that dark energy and cosmic acceleration are a failure of general relativity on very large scales, larger than superclusters.[citation needed] However most attempts at modifying general relativity have turned out to be either equivalent to theories of quintessence, or inconsistent with observations.[citation needed] Other ideas for dark energy have come from string theory, brane cosmology and the holographic principle, but have not yet proved[citation needed] as compellingly as quintessence and the cosmological constant.

On string theory, an article in the journal Nature described:

String theories, popular with many particle physicists, make it possible, even desirable, to think that the observable universe is just one of 10500 universes in a grander multiverse, says Leonard Susskind, a cosmologist at Stanford University in California. The vacuum energy will have different values in different universes, and in many or most it might indeed be vast. But it must be small in ours because it is only in such a universe that observers such as ourselves can evolve.
—[39]

Paul Steinhardt in the same article criticizes string theory's explanation of dark energy stating "...Anthropics and randomness don't explain anything... I am disappointed with what most theorists are willing to accept".[39]