• 

  Erik Thompson

  饰：Self - Narrator,

• 

  Kevin R. Grazier

  饰：Self - Planetary Scientist,(as Kevin Grazier)

• 

  Lucianne Walkowicz

  饰：Self - Princeton University

• 

  Alex Filippenko

  饰：Self - Ask 'The Universe'

• 

  Seth Shostak

  饰：Self - SETI Institute

• 

  Clifford V. Johnson

  饰：Self - Univ. of Southern California,(as Clifford Johnson)