What is a black hole? Learn about frame dragging, space-time, cosmic strings, and what they mean to time-travelers. This is a very interesting clip that uses CG graphics, scientific discussion, and comprehensive narration to postulate...

How does a massive star go supernova? This video is a follow-up to the Khan Academy video on the life cycle of massive stars, explaining the chemical collapse that results in a supernova. Sal explains the process with neutron stars and...

Part two of this three-part series asks us to think what life would be like if we lived in a binary star system. We are also introduced to black holes and Einstein's theory of relativity. A great clip shown in its three-part entirety or...

Part three concludes "A Practical Guide to the Universe," completing the description of the Big Bang Theory and what it means. This episode touches on light travel, light speed, and what that means in relation to what we see. While this...