Discover how astrophysicists map the universe. Focus on the tricky problem of calculating distances, seeing how a collection of overlapping techniques provide a "cosmic distance ladder" that works from nearby planets (by means of radar) to stars and galaxies (using parallax and Cepheid variable stars) to far distant galaxies (by observing a type of supernova with a standard intrinsic brightness).

Unlike the well-founded theories you've studied so far in this series, turn to one that is as-yet-unproven -- but mindboggling in its implications. Cosmic inflation proposes that a period of explosive expansion occurred in the first instants of the Big Bang. This startling idea accounts for two puzzling features of today's universe: the observed uniformity of matter and the flat geometry of space.

If you have a clever anecdote, an interesting memory, a new way to explain how something works, or an opinion on a social or political issue, then you have an essay in you. Unlike a novel, history book, or scientific publication, essays provide you with the versatility to express all the various facets that make you you. The concise and direct nature of an essay means that you may tap into your sense of wit, share your individual point of view, persuade...

Taught by noted physicist Dr. Don Lincoln of the Fermi National Accelerator Laboratory, this course follows the search for a theory that explains all physical reality-a theory of everything. Dr. Lincoln covers recent developments in particle physics and cosmology, plus the background needed to appreciate the centuries-long search for this holy grail of science. Only high-school-level math is used.

Suleiman the Magnificent presided over the zenith of the Ottoman Empire. You'll learn how, during his 46-year reign, he expanded civil bureaucracy, waged a naval war in the Mediterranean against Habsburg Spain, and also altered the imperial succession - sowing what some historians consider the seeds of the empire's downfall.

Every time you watch baseball, you’re participating in the latest chapter of a compelling story that goes back hundreds of years. In 24 lectures that paint a portrait of the sport’s remarkable past and take you from the decades before the Civil War to the pivotal year of 1920, Play Ball! The Rise of Baseball as America’s Pastime strikes a perfect balance between sports lore and cultural history.

A light -hearted romp with Jon Scieszka, beloved, award winning author/illustrator and the first National Ambassador for Young People's Literature. Get to know him as he discusses his life and aspirations.

Part biography, part day-in-the-life, this is a look into the mind and onto the pages of this prolific and well-loved children's book illustrator David McPhail.

One of the CIA's first major setbacks was the tragic failure of the Hungarian uprising, despite the agency's attempts to liberate the Eastern Bloc countries during the early 1950s. Here, investigate CIA efforts to organize anti-communist Eastern European emigres to liberate their homelands and the creation of Radio Free Europe to counteract communist-controlled media.

Amos McGee was a zookeeper who always made time for his animal friends. One day, when his sniffles and sneezes prevented him from going to the zoo, he received some unexpected guests. This is a gently humorous tale of friendship and dedication. Includes an interview with Philip and Erin Stead.