http://story.news.yahoo.com/news?tm...sc_space/leakinggravitymayexplaincosmicpuzzle I've never been very comfortable with the idea of dark energy; it seems like a copout explanation, so that physicists don't have to admit to not knowing what is causing the accelerating expansion of the universe... What do you guys think of this "gravity leak" hypothesis? It makes sense to me, but common sense is very often wrong in physics. It's years away from being testable, as is the string theory which it is based upon.
I'm not even going to pretend I understand enough physics to dabble with this. Either theres some cosmological constant causing its faster expansion, but why would an empty nothingness create a vacuum? or there are particles disappearing and reappearing in other dimensions or outside the universe, both sound really far fetched to me. Or theres some kinda gravitational energy outside the universe... I'm gonna go lie down.
Its interesting though just as theoretical as others. It leans very heavily on string theory which in itself is unproven, although the multiple dimension theories do seem to be gaining momentum these days, with indirect experiements now conceivable. Though a dark galaxy was recently discovered, though we still dont know what is made of, we know its there, its huge and it contains a lot of hydrogen and more stuff we dont know and it dont emit any light.
As I've said before I've got huge problems with string theory, and I can't understand why someone would "borrow" from one of the most purely theoretical, unproven ideas out there to try and solve a problem. Usually people base new theories on sound, or at least somewhat provable ideas. I think dark energy is very very interesting, because if there was such a thing, I wonder how it could ever be detected.
Im starting to believe superstring theory a little more than I used to. Im still not happy about taking a theory with no experimental evidence, smacks a little of religious thinking to my mind. You can prove a lot of things with maths, one thing you can prove is that we have a greater the 50% chance of living for ever. A lot of physics is about taking maths and seeing how it relates to life, to me superstring theory does not do this, at the moment it is maths not physics. In physics you do a lot of things mathematicians dont like such as implying infinity is a number, or at least treating it as one in equations. We discard solutions to equations for no reason other than one solution makes no physical sense. It is common to have a solution with more than one answer where one solution is positive and another negative. In the case of energy we usually discard the negative term with the logic, you cant have a negative energy. When solving the Dirac equation for the electron, Dirac found it had 2 solutions one positive and one negative. One solution represented the electron however the second part made no sense to known physics, Dirac didn't discard the second one but said it could represent an as of yet unknown particle. 10 years later the positron was experimentally found. That was a huge success for QED (Quantum electrodynamics) which went on to predict the vast majority of known particles before they were found experimentally.
Its greatest success was finally uniting spin with the rest of quantum theory, although this has been superceeded by you next thread
