# Introductory Astronomy Videos

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## Module 3: Relativity and Gravity

**Supplements and Credits**

### Supplement the videos with "OpenStax Astronomy"

### 01: Faraday, Maxwell and the Aether

Michael Faraday and James Clerk Maxwell finalize and culminate the wave theory of light. Faraday gives us our best picture of how light “looks” and Maxwell gives us the four equations that unify electricity, magnetism and light. Also, Herchel’s discovery of infrared, and others too!

### 02: The Speed of Light and the Michelson Morley Experiment

What is the speed of light? What do the waves of light travel in? What do we know about how light gets here from there? The answers are even more puzzling. In this one, we learn that the waves of light can still be waves, even if they don’t actually “wave” anything. Nature starts to show us just how strange she is.

### 03: The Great Relativistic Conundrum

Once upon a time, there was classical physics. It had Galilean Relativity, Newtonian Mechanics and Maxwell's Laws of Electromagnetism. But, these three things, while wildly successful, did not fit together at all. Let's see why.

### 04: Special Relativity's Implications

Wherein we chat about the postulates of Special Relativity, and three of its main implications: desynchronization of clocks, time dilation and length contraction. Here are some good resources for special relativity.

### 05: Special Relativity in Detail

Wherein we detail the effects of time dilation, length contraction and clock desynchronization. We also chat about muon decay which demonstrates this effect.

### 06: General Relativity Raison d'être

General Relativity arises out of our need to reconcile the issues of Newtonian Gravity. It has some problems that only rethinking Gravity can solve.

- Equivalence principle
- What is Mass?
- Newton's Cannonball
- International Space Station
- A revised version of David Bowie's Space Oddity, recorded by Commander Chris Hadfield on board the International Space Station.
- There is no problem so bad that you can't make it worse.
- Star Trek's "Gravity Plating" (Fiction...)

### 07: General Relativity Curvature and Tests

General Relativity is one of the most successful theories of Physics. It helps us give a mechanism to gravity, and allows for testable predictions. We'll chat about the Correspondence Principle, The Equivalence Principle, intertial versus gravitational mass, and the nature of spacetime curvature and how it's measured. We'll chat about various tests of general relativity, and how they showed that it's the best explanation so far to the nature of space, time and gravity.

- Hulse–Taylor binary showing gravitational waves
- Eötvös experiment
- Inertial vs. gravitational mass
- Equivalence Principle
- Gravity Probe B
- LIGO: Laser Interferometer Gravitational Wave Observatory
- How Your GPS Uses Einstein's Relativity
- Einstein, Eddington and the 1919 Eclipse
- The Precession of the Perihelion of Mercury
- Tests of general relativity
- Parallel Transport
- Correspondence principle
- Popular Books on General Relativity: Black Holes and Time Warps
- Popular Books on General Relativity: The Whole Shebang
- Introductory Textbook on Special Relativity
- Introductory Textbook on General Relativity 1
- Introductory Textbook on General Relativity 2

### 08: General Relativity and the Bending of Light's Path

General Relativity has many interesting results. In this first of two, I try to show how we can more intuitively understand what curvature of spacetime means. In this one, we look at the Equivalence Principle and show how it requires that light's path is bent according to a distant observer, but if you're falling along with the light, the path looks straight to you

### 09: General Relativity and the Slowing of Time by Gravity

We chat about how light is redshifted as it rises out of a gravity well, and how time runs slower in a gravity well compared to clocks far away. We also dare to ask "into where does space curve."

### 10: The Tides

Wherein we discuss the nature of the tides and what causes them.

### 11: Faster Than Light Tachyons, Causality and Tacos

What happens when you go faster than light? Can you go faster than light? (well, no, but let's chat anyway). And how do we know that we can't go faster than light? Why does going faster than light mean traveling into the past?