Sagan discusses comets and asteroids as planetary impactors, giving recent examples of the Tunguska event and a lunar impact described by Canterbury monks in 1178. It moves to a description of the environment of Venus, from the previous fantastic theories of people such as Immanuel Velikovsky to the information gained by the Venera landers and its implications for Earth's greenhouse effect. The Cosmos Update highlights the connection to global warming.

This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

Push the limits of your imagination as astronomers attempt to grasp the mind-boggling extremes of size, distance and speed within our universe by bringing them down to earth. In this episode, our cast uses awesome analogies to bring the biggest objects, farthest distances and fastest speeds down to earth. To truly understand the scale of the cosmos, we jump behind the wheel of monster trucks, scale the Golden Gate Bridge, and race across the desert in a rocket-powered car.

See as never before in this series the inner workings of our world, and explore black holes, supernovae, neutron stars, dark energy, and all the titanic forces that make us. A users guide to the cosmos from the big bang to galaxies, stars, planets and moons. Where did it all come from and how does it all fit together. A primer for anyone who has ever looked up at the night sky and wondered". Beneath the hood of your car lies the history of the Universe. The iron in your chassis, the gold in your stereo and the copper in your electronics all owe their existence to violent cosmic events that took place billions of years ago.

On November 25th, 1915, Einstein published his greatest work: General Relativity. The theory transformed our understanding of nature’s laws and the entire history of the cosmos, reaching back to the origin of time itself. Now, in celebration of the 100th anniversary of Einstein’s achievement, discover the inside story of Einstein’s masterpiece". The story begins with the intuitive thought experiments that set Einstein off on his quest and traces the revolution in cosmology that is still playing out in today’s labs and observatories. Discover the simple but powerful ideas at the heart of relativity, illuminating the theory—and Einstein’s brilliance—as never before. From the first spark of an idea to the discovery of the expanding universe, the Big Bang, black holes, and dark energy, NOVA uncovers the inspired insights and brilliant breakthroughs of “the perfect theory.”

25 years ago, NASA launched one of the most ambitious experiments in the history of astronomy: the Hubble Space Telescope. In honor of Hubble's landmark anniversary, know the remarkable story of the telescope that forever changed our understanding of the cosmos and our place in it". But amazingly, when the telescope first sent images back to earth, it seemed that the entire project was a massive failure; a one-millimeter engineering blunder had turned the billion-dollar telescope into an object of ridicule. It fell to five heroic astronauts in a daring mission to return Hubble to the cutting edge of science. Hear from the scientists and engineers on the front line who tell the amazing Hubble story as never before. This single telescope has helped astronomers pinpoint the age of the universe, revealed the birthplace of stars and planets, advanced our understanding of dark energy and cosmic expansion, and uncovered black holes lurking at the heart of galaxies. For more than a generation, Hubble's stunning images have brought the beauty of the heavens to millions, revealing a cosmos richer and more wondrous than we ever imagined. Join us for the story of this magnificent machine and its astonishing discoveries.