Howdy, I am having difficulty visualizing the idea that in m-theory, strings are 1 dimensional hunks-o-vibrating energy which can be open or closed. How can a one dimensional construct achieve a 'closed' state?
Well, ``one dimensional'' just means that you can describe any location with one coordinate. So it's just the same as if you drew a circle on a piece of paper---you only need one coordinate to tell you where you are on the circle, so the circle is a one dimensional shape. The mathematicians here may cringe at this, but it is what we mean be ``dimension'' in physics.
