James Lurie

Narrator (voice)

Seth Shostak

Self - SETI Institute

Nick Pope

Self - U.K. Ministry of Defense

Brian De Toy

Self - Director of Defense Studies, West Point

Stephen Hawking

Self - Theoretical Physicist (archive footage)

Paul Springer

Self - USAF Air Command and Staff College

Travis Taylor

Self - Physicist & Author

Bob Boan

Self - Co-Author, Alien Invasion: How to Defend Earth