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PHVSICS OF THE IMPOSSIBLE
what is waving? Light can pass through billions of light-years of empty
space, but empty space is a vacuum, devoid of any material. So what is
waving in the vacuum? With Raluza's theory we had a concrete proposal to answer this problem: light is ripples in the fifth dimension.
Maxwell's equations, which accurately describe all the properties of
light, emerge simply as the equations for waves traveling in the fifth dimension.
Imagine fish swimming in a shallow pond. They might never suspect the presence of a third dimension, because their eyes point to the
side, and they can only swim forward and backward, left and right. A
third dimension to them might appear impossible. But then imagine it
rains on the pond. Although they cannot see the third dimension, they
can clearly see the shadows of the ripples on the surface of the pond.
In the same way, Kaluza's theory explained light as ripples traveling on
the fifth dimension.
Raluza also gave an answer as to where the fifth dimension was.
Since we see no evidence of a fifth dimension, it must have "curled up"
so small that it cannot be observed. (Imagine taking a two-dimensional
sheet of paper and rolling it up tightly into a cylinder. From a distance,
the cylinder looks like a one-dimensional line. In this way, a two-dimensional object has been turned into a one-dimensional object by
curling it up.)
Raluza's paper initially created a sensation. But in the coming
years, objections were found to his theory. What was the size of this
new fifth dimension? How did it curl up? No answers could be found.
For decades Einstein would work on this theory in fits and starts.
After he passed away in 1955, the theory was soon forgotten, becoming
just a strange footnote to the evolution of physics.
STRING THEORY
All this has changed with the coming of a startling new theory, called
the superstring theory. By the 1980s physicists were drowning in a sea
of subatomic particles. Every time they smashed an atom apart with
PHVSICS OF THE IMPOSSIBLE
what is waving? Light can pass through billions of light-years of empty
space, but empty space is a vacuum, devoid of any material. So what is
waving in the vacuum? With Raluza's theory we had a concrete proposal to answer this problem: light is ripples in the fifth dimension.
Maxwell's equations, which accurately describe all the properties of
light, emerge simply as the equations for waves traveling in the fifth dimension.
Imagine fish swimming in a shallow pond. They might never suspect the presence of a third dimension, because their eyes point to the
side, and they can only swim forward and backward, left and right. A
third dimension to them might appear impossible. But then imagine it
rains on the pond. Although they cannot see the third dimension, they
can clearly see the shadows of the ripples on the surface of the pond.
In the same way, Kaluza's theory explained light as ripples traveling on
the fifth dimension.
Raluza also gave an answer as to where the fifth dimension was.
Since we see no evidence of a fifth dimension, it must have "curled up"
so small that it cannot be observed. (Imagine taking a two-dimensional
sheet of paper and rolling it up tightly into a cylinder. From a distance,
the cylinder looks like a one-dimensional line. In this way, a two-dimensional object has been turned into a one-dimensional object by
curling it up.)
Raluza's paper initially created a sensation. But in the coming
years, objections were found to his theory. What was the size of this
new fifth dimension? How did it curl up? No answers could be found.
For decades Einstein would work on this theory in fits and starts.
After he passed away in 1955, the theory was soon forgotten, becoming
just a strange footnote to the evolution of physics.
STRING THEORY
All this has changed with the coming of a startling new theory, called
the superstring theory. By the 1980s physicists were drowning in a sea
of subatomic particles. Every time they smashed an atom apart with