A Reassuring Fable • 1989 • episode "3/10" • The Sagan Series

11:16

Today on Crash Course Astronomy, Phil invites you to head outside and take a look at all the incredible things you can see with your naked eye.

#2 • Crash Course Astronomy • Astronomy

11:49

Today Phil explains that YES, there are other planets out there and astonomers have a lot of methods for detecting them. Nearly 2000 have been found so far. The most successful method is using transits, where a planet physically passes in front of its parent star, producing a measurable dip in the star’s light. Another is to measuring the Doppler shift in a star’s light due to reflexive motion as the planet orbits. Exoplanets appear to orbit nearly every kind of star, and we’ve even found planets that are the same size as Earth. We think there may be many billions of Earth-like planets in our galaxy.

27 • Crash Course Astronomy • 2015 • Astronomy

11:54

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.

21 • Crash Course Astronomy • 2015 • Astronomy

42:56

The discovery of gravity waves in early 2013 was huge news around the world ... and so was the retraction after the scientists realized they'd made a mistake. This is a dramatic human story of brave scientists and big science in action at the South Pole.

2015 • Astronomy

3:52

Carl Sagan talks about religion and the universe

3/10 • The Sagan Series • 1989 • Astronomy

58:39

Horizon takes the ultimate trip into the unknown, to explore a dizzying world of cosmic bounces, rips and multiple universes, and finds out what happened before the big bang.

Horizon • 2010 • Astronomy