Subjects: Astronomy

The study of stellar evolution is presented by examining the birth of stars. Different types of nebulae are introduced and the necessary ingredients to produce a star: dust, gas, gravity, and maybe a little push are discussed. The mass-luminosity relation is reintroduced and suggests the role that mass will play in the life and death of a star.

This lesson details the life and the death of stars. The fact that stars spend most of their lives on the main sequence consuming their nuclear fuel in a stable manner is detailed and illustrated, as well as how a star’s mass determines how quickly it consumes its fuel, how long it will live and how it will die. A presentation of the study of stellar remnants, the leftover products after a star dies, concludes the lesson and leads us to the topic of the next lesson, neutron stars and black holes.

This lesson describes the fascinating objects that remain after the deaths of large stars-neutron stars and black holes. Gamma-ray bursts and hypernovae are presented as some of the most energetic objects in the universe.

Most discussions of galaxies begin with our very own Milky Way. This lesson presents the history of the study of the size and scale of our galaxy and our place in it. The anatomy of the galaxy is introduced and the mapping techniques are unveiled.

This video lesson looks at the classification of galaxies in general, and discusses the fact that, when these “island universes” were discovered, how the perceived size of our universe increased immensely. It goes on to describe distance indicators and introduces the Hubble Law. The lesson ends with interaction and evolution of galaxies and with a sneak peek into the furthest depths of the universe

This lesson begins with an explanation of the processes that allowed the planets in this part of the solar system to grow to such large sizes. How the gravity of Jupiter produces tidal heating of Io and Europa, causing the extensive volcanic activity on Io and a liquid ocean beneath the surface of Europa is explained. Saturn’s interior and atmosphere are compared with those of Jupiter. The formation and characteristics of the ice giants Uranus and Neptune are also discussed.

Astronomy: Observations and Theories explores a broad range of astronomy topics, concepts, and principles, from the motions of the visible sky to dark matter, from our own planet to the stars and galaxies.

A presentation on the foundations of astronomy, The Birth of Astronomy examines the observations, theories, and contributions of Aristotle, Ptolemy, and other ancient scientists and philosophers. Copernicus, Tycho Brahe, Kepler, Galileo, and Sir Isaac Newton’s contributions are discussed throughout this lesson.

This lesson describes the thermonuclear process in the core of the sun, identifying the layers of the interior and atmosphere showing spectacular pictures of surface features, such as granulation and sunspots. The magnetic cycle and magnetic effects on the surface are also introduced. Discussions of how the sun affects Earth’s climate conclude the lesson.

To determine how bright a star actually is, we need to know how far away it is. This lesson illustrates how to find distance to nearby stars and how to plot them on an H-R diagram. It also shows why binary stars are important for the study of stars and their mass-luminosity relation.