Professor Dave Explains
Dark Matter and Dark Energy: The Frontier of Astronomy
For a while now, we've been discussing all of things we know about the universe. What about some of the things we don't know? If we look to the current frontier of astronomy, we find two mystifying concepts, dark matter and dark energy....
MinutePhysics
Do We Expand With the Universe?
The cat's out of the bag (or off the leash, in this case) regarding the expansion of the universe. In this intriguing episode, the narrator explains that space is expanding, not the objects within it. He also tells how expansion...
Khan Academy
Hubble's Law, Scale of the Universe, Cosmology and Astronomy
Sal defines and explains the premise of Hubble's Law and then uses trigonometry to show the relationship between velocity and distance. He explains that as the universe expands, objects get farther away from each other; as objects move...
Khan Academy
Radius of Observable Universe, Scale of the Universe, Cosmology and Astronomy
The concept of the universe can be incredibly complex on both physical and mathematical levels. Yet Salman Khan can explain concepts that lead to conclusions about the universe's size. He uses intriguing diagrams and presents information...
Other
Physics Girl: Is Energy Always Conserved?
When light passes through the universe and is redshifted by the expansion of space itself, how is energy conserved? The stretched light has a longer wavelength and therefore a lower energy. Is energy conserved? If so, where does it go?...
Crash Course
Crash Course Big History #201: Why Cosmic Evolution Matters
This video that discusses why cosmic evolution matters including the rapid growth of after the Big Bang beginning with cosmic inflation and continuing through external inflation to theories of how the universe might end.
Khan Academy
Khan Academy: Ways of Knowing Introduction to Cosmology
The history of the Universe decorates the night sky. Learn how to watch this history by studying cosmic light emissions. [6:22]
Science Friday Initiative
Science Friday: Adam Riess: One Cosmic Puzzle Solved, Many to Go
Nobel Prize-winning astrophysicist Adam Riess discusses the mysterious force known as dark energy in this audio recording. Learn how he believes this dark energy is accelerating the expansion of the universe. [22:36]