This episode provides an overview of the nature of electromagnetism, as discovered through the work of Michael Faraday. Tyson explains how the idea of another force of nature, similar to gravitational forces, had been postulated by Isaac Newton before. Tyson continues on Faraday, coming from poor beginnings, would end up becoming interested in studying electricity after reading books and seeing lectures by Humphry Davy at the Royal Institution. Davy would hire Faraday after seeing extensive notes he had taken to act as his secretary and lab assistant. After Davy and chemist William Hyde Wollaston unsuccessfully tried to build on Hans Christian Ørsted's discovery of the electromagnetic phenomena to harness the ability to create motion from electricity, Faraday was able to create his own device to create the first electric motor by applying electricity aligned along a magnet. Davy, bitter over Faraday's breakthrough, put Faraday on the task of improving the quality of high-quality optical glass, preventing Faraday from continuing his research. Faraday, undeterred, continued to work in the Royal Institution, and created the Christmas Lectures designed to teach science to children. Following Davy's death, Faraday returned to full time efforts studying electromagnetism, creating the first electrical generator by inserting a magnet in a coil of wires. Tyson continues to note that despite losing some of his mental capacity, Faraday concluded that electricity and magnetism were connected by unseen fields, and postulated that light may also be tied to these forces. Using a sample of the optical glass that Davy had him make, Faraday discovered that an applied magnetic field could affect the polarization of light passing through the glass sample (a dielectric material), leading to what is called the Faraday effect and connecting these three forces. Faraday postulated that these fields existed across the planet, which would later by called Earth's magnetic field generated by the rotating molten iron inner core, as well as the phenomena that caused the planets to rotate around the sun. Faraday's work was initially rejected by the scientific community due to his lack of mathematical support, but James Clerk Maxwell would later come to rework Faraday's theories into the Maxwell's equations that validated Faraday's theories. Their combined efforts created the basis of science that drives the principles of modern communications today.
Category:Science Duration:39:00 Series: Cosmos 2014
Tyson begins the episode by explaining the nature of the speed of light and how much of what is seen of the observable universe is from light emanated from billions of years in the past. Tyson further explains how modern astronomy has used such analyzes via deep time to identify the Big Bang event and the age of the universe. Tyson proceeds to describe how the work of Isaac Newton, William Herschel, and James Clerk Maxwell contributed to understanding the nature of electromagnetic waves and gravitational force, and how this work led towards Albert Einstein's Theory of Relativity, that the speed of light is a fundamental constant of the universe and gravity can be seen as distortion of the fabric of space-time. Tyson describes the concept of dark stars as postulated by John Michell which are not visible but detectable by tracking other stars trapped within their gravity wells, an idea Herschel used to discover binary stars. Tyson then describes the nature of black holes, their enormous gravitational forces that can even capture light, and their discovery via X-ray sources such as Cygnus X-1. Tyson uses the Ship of Imagination to provide a postulate of the warping of spacetime and time dilation as one enters the event horizon of the black hole, and the possibility that these may lead to other points within our universe or others, or even time travel. Tyson ends on noting that Herschel's son, John would be inspired by his father to continue to document the known stars as well as contributions towards photography that play on the same nature of deep time used by astronomers.
Category:Science Duration:41:00 Series: Cosmos 2014
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