Ideas about time and space are explored in the changes that constellations undergo over time, the redshift and blue shift measured in interstellar objects, time dilation in Albert Einstein's theory of relativity, the designs of both Leonardo da Vinci and spacecraft that could travel near light speed, time travel and its hypothetical effects on human history, the origins of the Solar System, the history of life, and the immensity of space. In Cosmos Update, the idea of faster-than-light travel by wormholes (researched by Kip Thorne and shown in Sagan’s novel Contact) is discussed.
Gamma-ray bursts are not only incredible to study, but their discovery has an epic story all its own. Today Phil takes you through some Cold War history and then dives into what we know. Bursts come in two rough varieties: Long and short. Long ones are from hypernovae, massive stars exploding, sending out twin beams of matter and energy. Short ones are from merging neutron stars. Both kinds are so energetic they are visible for billions of light years, and both are also the birth announcements of black holes.
Dallas Campbell looks back through almost 50 years of the Horizon archives to chart the scientific breakthroughs that have transformed our understanding of the universe. From Einstein's concept of spacetime to alien planets and extra dimensions, science has revealed a cosmos that is more bizarre and more spectacular than could have ever been imagined. But with every breakthrough, even more intriguing mysteries that lie beyond are found. This great journey of discovery is only just beginning.
This episode concentrates on how the universe was made in the Big Bang and how scientists predict it could end similarly as it continues to expand. Several theories are covered including the "Big Crunch" where the universe shrinks back to its original size, and the "Big Chill" with the universe slowly freezing to death.