PBS
Pbs Learning Media: Sagan on Time Travel
Astronomer Carl Sagan discusses the possibility of time travel in this audio-enhanced interview from the NOVAWeb site.
PBS
Pbs Teachers: Time Travel
Use this NOVA lesson to discuss the nature of time and the grandfather paradox. Examine time from different perspectives by plotting ages on a timeline, estimating how long a minute is and imagining going back in time to change something...