Today Phil’s explaining the stars and how they can be categorized using their spectra. Together with their distance, this provides a wealth of information about them including their luminosity, size, and temperature. The HR diagram plots stars’ luminosity versus temperature, and most stars fall along the main sequence, where they live most of their lives.
10m • 2015 • Crash Course Astronomy
This visually stunning program chronicles a sweeping journey, from 1609 when Galileo revealed mankind's place in the galaxy to 2009, the International Year of Astronomy. Narrated by NOVA's Neil deGrasse Tyson, the compelling program takes viewers on an adventure through the heavens and around the globe, visiting the world's leading astronomers, cosmologists and observatories. The Interstellar Studios production team traveled the globe to interview leading astronomers and cosmologists from the world's renowned universities and observatories. The producers sought the most acute minds at great astronomical centers including the European Southern Observatory, Institute for Astronomy, SETI Institute, Space Telescope Science Institute, Anglo-Australian Observatory, and Harvard University. They journeyed across five continents to visually write the story of the past and the future of telescopes, astronomy, and our ever-changing perception of the cosmos. Compelling interviews throughout the film leave no stone unturned. A carefully chosen array of today's leading astronomers explain concepts ranging from Galileo's act of revealing the telescopic cosmos to humanity and challenging religious teachings of the day, to the latest discoveries in space, including startling new ideas about life on other planets and dark energy – a mysterious vacuum energy that is accelerating the expansion of the universe. On the horizon, viewers learn of emergent telescopes the size of stadiums. With unprecedented resolution and light gathering, these enormous new instruments will look back to the initial moments of the Big Bang and – like Galileo's first telescopic observations – will reshape our model of the universe.
55m • 2009