What are the dimensions of strings?

In summary, string theory suggests that strings are exactly 1-dimensional and their length is not necessarily bound by the Planck scale. There are different types of strings, including fundamental strings and QCD strings, which can also be thought of as 1-branes. While fundamental strings are near the Planck scale and do not expand easily, black holes have the energy to extend strings to immense sizes. Some theories also suggest that cosmological strings stretching across the universe may be remnants of the big bang.
  • #1
ShadowVegan
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According to string theory, are strings Planck length in 1 dimension and 0 in all other dimensions? Or more than Planck length in 1 dimension and exactly Planck length in all other dimensions? Or something else? Thanks.
 
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  • #2
The string is exactly 1-dimensional. I don't believe the length of the string is bounded to be at or below the Planck scale (obviously it must be close, but there is typically some wiggle room of an order of magnitude or so).
 
  • #3
Presumably you are thinking of fundamental strings...that's what's usually discussed in these forums...there are a different "brand" of string that makes up elementary nuclear particles...called QCD strings and those are huge maybe 1020 times longer. Strings can also be thought of as 1 branes...one dimensional (length only) branes...particles would be zero branes (no dimensions). So strings are a special class of branes. (I think this depends on the particular string theory.)

The former are supposedly near the Planck scale, so one dimension and largr than Planck scale, yet there IS a type of unity between the two types of strings. Leonard Susskind says "you could suspend 1040 trucks from a fundamental string"...(gotta love THAT measurement unit!) they don't expand (extend) very easily.

Susskind points out that black holes, even the supersized giants at the center of galaxies, DO have the energy needed to extend strings to immense size..such that a black hole might consist of a single string! As an example, one theory posits the horizon of a black hole as a single tangled string with quantum fluctuations...when a bump in the string appears on the horizon, it appears to an outside observer as an open string...ends connected to the horizon...and when one breaks off due to quantum zero point energy...carrying gravitational energy, voila, Hawking radiation!
 
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  • #4
Now that I think about it again, I know I read there are hints that cosmological scale strings that might stretch across the universe might be remnants of a big bang...don't recall the source...so "strings" might vary in size from just above Planck scale to cosmological size.
 

Related to What are the dimensions of strings?

1. What is the definition of string dimensions?

String dimensions refer to the physical properties that describe a string, such as its length, width, and thickness.

2. Why are string dimensions important in science?

String dimensions are important because they can affect the behavior and properties of the string. For example, the length of a string can determine the frequency of its vibrations, which is crucial in fields such as acoustics and music.

3. How are string dimensions measured?

String dimensions are typically measured using a ruler or caliper to determine the length and a micrometer or thickness gauge to measure the width and thickness. In some cases, specialized instruments such as laser interferometers may be used for more precise measurements.

4. What factors can affect the dimensions of a string?

The dimensions of a string can be affected by factors such as tension, temperature, and material properties. For example, a string may stretch or contract when under tension, and its dimensions may change with temperature due to thermal expansion or contraction.

5. How do string dimensions vary among different types of strings?

The dimensions of a string can vary greatly depending on its purpose and material composition. For instance, guitar strings are typically longer and thicker than violin strings, and steel strings may have different dimensions than nylon strings due to their different material properties.

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