Erik Dellums

Himself - Narrator

Mike Rowe

Himself - Narrator

Chris Mckay

Self - Astrobiologist

Carly Howett

Self - Planetary Scientist

Nina Lanza

Self - Planetary Scientist

Hakeem Muata Oluseyi

Self - Astrophysicist

Amber Straughn

Self - Astrophysicist

Max Tegmark

Self - Theoretical Physicist

Moogega Cooper

Self - Planetary Protection Engineer

Alex Philippenko

Self - Astrophysicis

Jani Radebaugh

Self - Planetary Scientist

Katie Freese

Self - Cosmologist

Dan Durda

Self - Planetary Scientist

Grant Tremblay

Self - Astrophysicist

Chiara Mingarelli

Self - Astrophysicist

Kevin J. Walsh

Acteur

Paul M Sutter

Acteur

Michelle Thaller

Acteur

Phil Plait

Self - Astronomer

James S. Bullock

Acteur

Richard Lintern

Himself - Narrator

Albert Einstein

Himself (Archive footage)

Lawrence Krauss

Himself

Michio Kaku

Himself