The Expanding Universe • 2025 • The Sky at Night

10:16

In today's Crash Course Astronomy, Phil takes a look at the explosive history of our cosmic backyard. We explore how we went from a giant ball of gas to the system of planets and other celestial objects we have today.

#9 • Crash Course Astronomy • Astronomy

60:25

Carl Sagan opens the program with a description of the cosmos and a "Spaceship of the Imagination" (shaped like a dandelion seed). The ship journeys through the universe's hundred billion galaxies, the Local Group, the Andromeda Galaxy, the Milky Way, the Orion Nebula, our Solar System, and finally the planet Earth. Eratosthenes' successful calculation of the circumference of Earth leads to a description of the ancient Library of Alexandria. Finally, the "Ages of Science" are described, before pulling back to the full span of the Cosmic Calendar. Note: This revised version of the series adds an introduction by Ann Druyan, in which she discusses some of the changes that occurred in the years after its broadcast.

1/13 • Cosmos: A Personal Voyage • 1980 • Astronomy

47:38

In 1972, the crew of Apollo 17 captured the iconic 'Blue Marble': the first photograph ever taken by an astronaut of the entire Earth. This photo had a profound effect on our perception of ourselves. Since then, Nasa has taken millions more. In this epic, powerful and revelatory documentary, a new generation of astronauts, including Tim Peake, use those images of the Earth from space to reveal the astonishing transformation humanity has wrought in the 45 years since 'Blue Marble'. Together, the astronauts provide an armchair tour of the change they've witnessed from orbit, as humankind etches our presence on the planet. Using stunning time-lapse sequences, the programme reveals how we are reshaping our world, for better and for worse: from the sprawling megacities of China to vast desert farms in the Middle East and from the melting snowcap of Kilimanjaro to giant solar arrays in Nevada.

2017 • Astronomy

12:00

Double stars are stars that appear to be near each other in the sky, but if they’re gravitationally bound together we call them binary stars. Many stars are actually part of binary or multiple systems. If they are close enough together they can actually touch other, merging into one peanut-shaped star. In some close binaries matter can flow from one star to the other, changing the way it ages. If one star is a white dwarf, this can cause periodic explosions, and possibly even lead to blowing up the entire star.

34 • Crash Course Astronomy • 2015 • Astronomy

58:18

Right now researchers are hunting for extra-terrestrial life on several fronts. To find out just how close we might be to a breakthrough, astrophysicist Dr Graham Phillips visits telescopes, swims among the stromatolites on the remote West Australian coastline, and chats with scientists from around the world

S1E3 • Catalyst: Series 18 • 2017 • Astronomy

44:01

See how little things like a stripped screw or a faulty toilet can become big emergencies when they happen in space.

S1E4 • Space Disasters • 2020 • Astronomy