Neil deGrasse Tyson (55)

Self - Host

Ann Druyan (64)

Unknown

John Steven Rocha (43)

Bellaramine (voice)

Paul Telfer (34)

Angry Scholar #2 (voice)

Jonathan Morgan Heit (13)

John Herschel (voice)

Cary Elwes (51)

Edmond Halley / Robert Hooke (voice)

Tom Konkle

Samuel Pepys (voice)

Alexander Siddig (48)

Isaac Newton (voice)

Alfred Molina (60)

Ibn al-Haytham (voice)

Richard Gere (64)

Clair Patterson (voice)

Marc Worden (37)

Harrison Brown (voice)

Kirsten Dunst (31)

Cecilia Payne (voice)

Marlee Matlin (48)

Annie Jump Cannon (voice)

Peggy Jo Jacobs

Margaret Harwood (voice)

Amanda Seyfried (28)

Marie Tharp (voice)

Stoney Emshwiller (55)

/ Guard (voice)

Christiane Amanpour (56)

Enheduanna (voice)

Michael Chochol

Jan Oort

André Sogliuzzo (47)

Weichelberger (voice) / Christopher Wren (voice)

Oliver Vaquer (64)

Joseph von Fraunhofer (voice)

Christopher Emerson (32)

/ Acolyte (voice)

Fred Tatasciore (45)

Democritus (voice)

Piotr Michael (25)

Lab Assistant (voice) / Edmund Muskie (voice)

Larry Cedar (59)

Unknown

Nick Jameson (63)

Unknown

Michael McConnohie (62)

Unknown

Enn Reitel (63)

/ Henry Norris Russell (voice)

Keythe Farley

/ (voice)

Masasa Moyo (44)

Unknown

Maria Frucci

Unknown