# Exploring String Dimensions in The Elegant Universe

• LogicalAtheist
In summary, "The Elegant Universe" discusses the onedimensional nature of strings and how they can still oscillate despite only having one dimension. The author explains that the string itself is a line and can be completely specified with one number, regardless of any curves or twists it may have. The book goes on to explore the multidimensionality of strings in more depth.
LogicalAtheist
Two days ago I bought THE ELEGANT UNIVERSE.

My first question is:

Mr. Greene states that a string is a one dimensionl string.

1. The nature of a string would require two dimensions, as I know it.

2. If these strings are to oscillate, needn't they be two dimensional?

3. How could it be one dimensional?

Is he meaning it's literally one dimensional, or is he being a bit lax..

Recall that a line is one dimensional.

You need to keep reading, he explains multi dimensionality of strings deeper in the book.

He actually means onedimensional.

Why do you say that "The nature of a string would require two dimensions"?

Imagine a cable, and make it extremely (infinitely) thin. In order to specify a point on it, you need only one number. By definition, it has then one dimension.

In order to oscillate, the can be embedded in a higher dimensional space, but the string itself does not need to have any more dimensions.

Maybe a rookie question, but can't the inverse square law of expanding energy/matter describe our dimensia?

ahrkron - Yes I understand, but the drawings show them as a loop. And he says they're like a rubber band. He doesn't say a straight string, he says a loop, and draws a loop.

A loop must be two dimensional.

Originally posted by LogicalAtheist
A loop must be two dimensional.

Only if you are talking about the "interior" of the loop.

However, the string is only the perimeter itself, which is a line. As such, any point on it can be completely specified via one number.

It doesn't matter if such line is straight or not.

In a similar way, the surface of a sphere is a two-dimensional space, just as a table top is; as far as the numner of dimensions goes, the apparent curvature (as seen from the 3D space in which both are embedded) does not matter.

Maybe this will help: think about a point living on the string, able to travel along it. Regardless of the curves and twists the string may have, the point only needs one number to know any "address" within its world.

Put in a different way, the structure of the manifold resembles that of any other line (straight lines included): a point on it has neighbors only in two directions (which you can call "forward" and "backward").

On the other hand, on a 2D space, each point has an infinity of directions to choose neighbors from, and it can characterize locally its neighborhood by using a copy of R2.

## 1. What is "The Elegant Universe"?

"The Elegant Universe" is a book and documentary series by physicist Brian Greene that explores the concept of string theory and its potential to unify the laws of physics.

## 2. What is string theory?

String theory is a theoretical framework that suggests that the fundamental building blocks of the universe are not particles, but rather tiny, vibrating strings. These strings exist in multiple dimensions and their vibrations determine the properties of particles and the forces between them.

## 3. How many dimensions does string theory propose?

String theory proposes that there are 10 dimensions in total - 9 spatial dimensions and 1 time dimension. However, these extra dimensions are thought to be compactified or "curled up" so that they are not observable at our scale.

## 4. How does string theory relate to the concept of space-time?

String theory suggests that space and time are not separate entities, but rather intertwined in a concept known as space-time. This concept helps to explain the effects of gravity and how it warps space and time.

## 5. What are the potential implications of string theory?

If string theory is proven to be true, it could potentially lead to a unified theory of physics, solving many of the mysteries and inconsistencies in our understanding of the universe. It could also have practical applications in fields such as quantum computing and space travel.

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