Cosmos: A Spacetime Odyssey, episode 10, The Electric Boy

Logo for the television series Cosmos: A Spacetime Odyssey. Fox Entertainment

This episode focuses on the discovery of electromagnetism, specifically through the work of Michael Faraday (1791 - 1867) and "how we learned to make electrons do our bidding." To place Faraday's work in context, host Neil deGrasse Tyson points out two contrasting mysteries in science:

  • Sir Isaac Newton sought to understand how gravity could act at a distance
  • As a young boy, Albert Einstein was famously inspired by how invisible forces from a magnet could move a compass needle.

    The answer to both of these mysteries is that the forces act through fields ... which Faraday discovered in the years between Newton and Einstein.

    Faraday's story is a fascinating one. Raised as a devoutly religious Christian, his faith was always a source of strength for him. He grew up poor and had no real education to speak of, but instead worked as a bookbinder. After attending a scientific presentation, he grew fascinated, and took it upon himself to create a transcript of the demonstration, bind it, and present it to the scientist Humphrey Davy (1778 - 1829). When Davy was blinded during a chemical experiment, he remembered Faraday and sought him out to help him with his work while he was blinded.

    Working together with Davy, Faraday began to experiment with electricity, figuring out how to use this seeming curiosity to create a spindle that spun in response to an electrical current. It was, in fact, the very first electric motor!

    Jealous of the attention that Faraday was getting among the scientific community, Davy assigned Faraday the task of trying to improve optical glass by reverse engineering the production methods used by the Bavarians. (Remember the work of Joseph Fraunhoffer from episode 5?) Faraday worked on the project for years with no success, although the glass he created would eventually prove useful.

    Years later, after suffering from some memory damage, he came up with a theory that perhaps the forces at a distance happened because of fields, invisible lines of force that connected magnets. He attempted an experiment to prove this, by using the fields to get polarized light to travel through a substance. All efforts failed ... until he used the glass brick from his work years earlier with Davy. The glass brick allowed light to pass when placed within an electric field ... proving that the electric field must in fact actually exist. For the first time, a scientist had shown that electromagnetic energy could manipulate the motion of light, which laid the groundwork for Einstein's insights in the following century!

    At age 60, when Faraday's physical and mental health was in decline, he went even further, conducting research with iron filings to show that the magnets were connected by invisible lines of force. We now know that these lines of force from the Earth's magnetic field itself are part of what is used by birds to guide their migratory journeys.

    Unfortunately, Faraday was a brilliant experimental physicist, but his lack of education meant that he could not handle the mathematics necessary to transform his insights into the mathematical language of modern physics (of the day).

    However, theoretical physicist James Clerk Maxwell came along and, realizing that Faraday's insights were crucial, gave them a firm theoretical and mathematical foundation. The resulting set of equations became known as Maxwell's equations and are the foundation of the modern, classical understanding of electrodynamics.

    Here is a key insight: Within the mathematical equations that Maxwell developed, he discovered that the equations were not static, as Faraday's experiments had predicted, but rather that they were dynamic, able to change and react in time. It was through the mathematical formulation of Faraday's fields that the foundation for our modern electromagnetic communications - including the recording and broadcast of Cosmos: A Spacetime Odyssey - became possible!

    Episode Information:

    The episode aired on May 11, 2014. It is 40 minutes long. The episode is available (as of the time of this writing) on the Cosmos website and through the streaming service Hulu.  The entire series is also available on blu-ray and DVD.