Theory of Theodor Kaluza and Oskar Klein. German and Swedish Physicists Famous for the Kaluza-Klein Concept. Brief biographies and work of physicists Theodor Kaluza and Oskar Klein, who conceived the idea of the higher level fifth-dimension of unifying forces.

Theodor Kaluza was a German mathematician and physicist, and Oskar Klein, a Swedish theoretical physicist. They are famous for the Kaluza-Klein theory which relates to field equations in five-dimensional space. Their idea is that fundamental forces can be unified by introducing additional dimensions, a concept that much later re-emerged in string theory.

### Brief Biography of Theodor Kaluza

Theodor Franz Eduard Kaluza was born in Ratibor, Germany on November 9, 1894. In 1919, he wrote to Einstein, in 1919, to explain his ideas about how to unify Einstein’s theory of relativity with Maxwell’s theory of light.

It tool almost two years before Einstein eventually saw the potential of Kaluza’s and to agree in publishing his theory. Kaluza became professor at Kiel University in 1935, after Einstein’s recommendation of his brilliance. He passed away in Germany, on January 19, 1954.

### Brief Biography of Oskar Klein

Oskar Klein was born in Mörby, Sweden in 1894. In 1917, aged 23, he worked with Niels Bohr in Copenhagen. In 1923, Klein marries Gerda Koch and moves to the University of Michigan.

While teaching electromagnetism he begins to consider introducing a fifth dimension in order to unify gravitational and electromagnetic fields. Two years later, he contracted hepatitis and returned to Copenhagen. In 1926, Klein becomes aware of Kaluza’s work, and publishes his own ideas in the science journal *Nature.* Oskar Klein passed away in Stockholm on February 5, 1977.

### Unification from Higher Dimensions

The common conception is that an infinitely small dot has no dimensions, that a line has one dimension. Dimensions can be drawn on a graph with the usual x, y and z coordinates. However, to describe how an object can alter, a fourth dimension — the dimension of time — is needed. This is quite obvious, much of basic science with the use of a ruler and time.

The theoretical physicists met with challenges the more they looked at Einstein’s theory of relativity and James Maxwell’s theory of light. They were convinced that there must be a way of joining them together, by creating a unified theory. This is where the fifth dimension comes in to play.

### Theodor Kaluza and Oskar Klein, and their Fifth Dimension

Kaluza and Klein independently came up with the same conclusion opening up a new era that even Einstein, who initially rejected the idea eventually embraced the concept of the fifth dimension and took trouble to publicize it to gain promotions for Kaluza and Klein.

All electromagnetic waves can be thought of as vibrations of this fifth dimension. The question is, Why can’t the fifth dimension be seen? The answer is that it is very small, curled up in a circle. Kaluza and Klein insisted that it is more than a matter a mathematical equation, however, it has a physical existence, that the distance traveled before a particle gets back to starting point, the circumference of the circle, is the size of this fifth dimension. The Kaluza-Klein theory was conceived.

### String Theory Enters the Scene

After the Kaluza-Klein theory, physicist worked on more standard models pf particles that provided the emergence of the string theory. This theory proposed that everything is made of strings, the smallest possible particles with a lent of 10 centimeters, no width, no height. A string has a fixed point in time and space. Mathematically, the string theory works in equations using 10 dimensions.

The Kaluza-Klein theory explains the existence of the six dimensions that cannot be ordinarily experienced.

### Importance of the Kaluza-Klein Theory

Although the general public was captivated by the brilliance of Albert Einstein and his theory of relativity, they were still coming to terms with it. Despite the manifestations of his work as shown in moving stars and exploding bombs, physicists still looked for further explanations in terms of electrodynamics and gravity, and decided that the three dimensions of space seen were not enough.

Theodor Kaluza and Oskar Klein conceived of the higher fifth dimension that significantly solved the problems and perplexity of the lower level dimensions.