This recording has several abrupt gains in amplitude (volume), so do not turn your local volume up too high when listening, or you may be surprised by the sudden increase in the sound level.

[00:00]	Black Holes
[00:42]	Escape Velocity
[05:34]	Black Hole Physics
[10:59]	Pilot & Explorer
[18:19]	Twin Paradox
[26:36]	Black Hole Physics (reprise)
[37:35]	Solar Black Hole
[40:00]	Solar Mass Black Hole
[43:04]	Million Solar Mass Black Hole

Learning Objectives

1. Relate the concept of escape velocity to a black hole (an object whose escape velocity is greater than the speed of light within the event horizon).

2. Visualize a black hole as an object with finite mass, infinite density, and zero size.

3. Understand how the strong increasing gravitational force of a black hole will separate your toes from your nose (due to the differential tidal force).

4. Visualize the consequences of gravitational fields affecting the passage of time.
   1. Time passes slower in the presence of a stronger gravitational field.
   2. Time is thus a relative quantity - there is no absolute clock keeping correct time.
   3. The difference in clock speeds can actually be measured by placing clocks closer to or further from the Earth's surface.

   4. A spacecraft approaching the event horizon of a black hole will thus appear to travel slower and slower, from the point of view of a distant observer.
   5. A spacecraft approaching the event horizon of a black hole will thus observe the rest of the universe fast-forwarding through the rest of its lifetime, from the point of view of the pilot.

5. Visualize the effect of gravitational lensing on a star field (strong gravity can bend light rays).

6. Understand how a black hole in a binary star system can gain fuel from its companion, creating an accretion disk.

7. Comprehend the consequences of replacing the Sun with a black hole.