• 
  David O'Brien

   Narrator (3 episodes, 2016)
• 
  Phil Plait

  Self - Astronomer
• 
  Grant Tremblay

  Self - Astrophysicist
• 
  Carly Howett

  Self - Planetary Scientist
• 
  Laura Danly

  Self - Astronomer
• 
  Brian Greene

  Self - Theoretical Physicist
• 
  Caleb Scharf

  Self - Astronomer
• 
  Alex Filippenko

  Self - Astrophysicist

• 
  Parker Sawyers

  Narrator
• 
  Seth Shostak

  Self - Astronomer
• 
  Peter Schultz

  Self - Planetary Scientist
• 
  Chris McKay

  Self - Astrobiologist
• 
  Bob Nichol

  Euclid Consortium
• 
  Carolyn Porco

  Self - Cassini Imaging Team Leader
• 
  Risa Wechsler

  Self - Cosmologist

• 
  Meenakshi Wadhwa

  Self - Planetary Scientist
• 
  Michelle Thaller

  Self - Astronomer
• 
  Hakeem Oluseyi

  Self - Astrophysicist