Lecture 22: Light the Messenger

What is ordinary matter made of? This lecture reviews the basic properties of matter from subatomic to atomic scales, introducing atomic structures, atomic number and chemical elements, isotopes, radioactivity, and half-life, ending with a brief overview of the four fundamental f ...  Show more

How do matter and light interact? This lecture is the first of two that will explore the interaction between light and ordinary matter, and how we measure that with spectroscopy. This lecture introduces the idea of internal energy as quantified by the temperature on the Absolute ...  Show more

There was a time when science and religion worked in harmony, as two parts of a celestial design. Astrologer and philosopher Johannes Kepler oversaw this marriage of theory and belief when he proposed the revolutionary laws of planetary motion in the early 17th century. Amidst pe ...  Show more

Melvyn Bragg and guests discuss the flow of particles from the outer region of the Sun which we observe in the Northern and Southern Lights, interacting with Earth's magnetosphere, and in comet tails that stream away from the Sun regardless of their own direction. One way of defi ...  Show more

Melvyn Bragg and guests discuss the pioneering Danish astronomer Tycho Brahe (1546 – 1601) whose charts offered an unprecedented level of accuracy.In 1572 Brahe's observations of a new star challenged the idea, inherited from Aristotle, that the heavens were unchanging. He went o ...  Show more

The sun is out, the weather is warm, and summer school is in session! Neil deGrasse Tyson, co-host Matt Kirshen, and astrophysicist Charles Liu answer fan-submitted questions on mathematics, the Big Bang, the laws of physics, neutrinos, relativity, Pluto, the smell of the Milk ...