Читать книгу String Theory For Dummies - Andrew Zimmerman Jones - Страница 108

Physicists now know that electricity and magnetism are both aspects of the same electromagnetic force. This force travels in the form of electromagnetic waves. We see a certain range of this electromagnetic energy in the form of visible light, but there are other forms, such as X-rays and microwaves, that we don’t see.

In the mid-1800s, James Clerk Maxwell took the work of Faraday and others and created a set of equations, known as Maxwell’s equations, that describe the forces of electricity and magnetism in terms of electromagnetic waves. An electromagnetic wave is shown in Figure 5-8.

FIGURE 5-8: The electric field and magnetic field are in step in an electromagnetic wave.

Maxwell’s equations allowed him to calculate the exact speed that an electromagnetic wave traveled. When Maxwell performed this calculation, he was amazed to find that he recognized the value. Electromagnetic waves move at exactly the speed of light!

Maxwell’s equations showed that visible light and electromagnetic waves are different manifestations of the same underlying phenomena. In other words, we see only a small range of the entire spectrum of electromagnetic waves that exist in our universe. Extending this unification to include all the forces of nature, including gravity, would ultimately lead to theories of quantum gravity such as string theory.