On a dry lakebed in Nevada, a group of friends build the first scale model of the solar system with complete planetary orbits: a true illustration of our place in the universe.
Earth has a companion in space so large that it rules our nights, our months, our ocean tides. Why Earth should have such a moon is one of the deepest mysteries of the Solar System. We tell the story of how the Earth’s satellite became the unlikely object of desire of the two Cold War superpowers.
Beginning with the separation of the fuzzy thinking and pious fraud of astrology from the careful observations of astronomy, Sagan follows the development of astronomical observation. Beginning with constellations and ceremonial calendars (such as those of the Anasazi), the story moves to the debate between Earth and Sun-centered models: Ptolemy and the geocentric worldview, Copernicus' theory, the data-gathering of Tycho Brahe, and the achievements of Johannes Kepler (Kepler's laws of planetary motion and the first science-fiction novel).
More than three decades after the debut of Carl Sagan's ground-breaking and iconic series, "Cosmos: A Personal Voyage," it's time once again to set sail for the stars. Host and astrophysicist Neil deGrasse Tyson sets off on the Ship of the Imagination to discover Earth's Cosmic Address and its coordinates in space and time. Viewers meet Renaissance Italy's Giordano Bruno, who had an epiphany about the infinite expanse of the universe. Then, Tyson walks across the Cosmic Calendar, on which all of time has been compressed into a year-at-a-glance calendar, from the Big Bang to the moment humans first make their appearance on the planet.
Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into gas, forming the long tail, and also releases dust that forms a different tail. We’ve visited comets up close and found them to be lumpy, with vents in the surface that release the gas as ice sublimates. Eons ago, comets (and asteroids) may have brought a lot of water to Earth -- as well as the ingredients for life.