Neil deGrasse Tyson

Self - Host

Ann Druyan

Carl Sagan

Self (archive footage), Self (voice) (archive footage)

Seth MacFarlane

President Harry S. Truman (voice), (voice), Giordano Bruno (voice), Sherwood Rowland (voice)

Sasha Sagan

Rachel Molly Gruber

Stoney Emshwiller

Guard (voice)

André Sogliuzzo

Weichelberger (voice), Christopher Wren (voice)

Christopher Emerson

Acolyte (voice)

Piotr Michael

Edmund Muskie (voice), Lab Assistant (voice)

Enn Reitel

Henry Norris Russell (voice)

Keythe Farley

(voice)

Patrick Stewart

William Herschel (voice)

Elizardo Torrez

Young Carl Sagan

Trang Vo

(voice), Birthmark Woman

John Steven Rocha

Bellaramine (voice)

Paul Telfer

Angry Scholar #2 (voice)

Jonathan Morgan Heit

John Herschel (voice)

Cary Elwes

Edmond Halley / Robert Hooke (voice)

Tom Konkle

Samuel Pepys (voice)

Alexander Siddig

Isaac Newton (voice)

Alfred Molina

Ibn al-Haytham (voice)

Richard Gere

Clair Patterson (voice)

Marc Worden

Harrison Brown (voice)

Kirsten Dunst

Cecilia Payne (voice)

Marlee Matlin

Annie Jump Cannon (voice)

Peggy Jo Jacobs

Margaret Harwood (voice)

Amanda Seyfried

Marie Tharp (voice)

Christiane Amanpour

Enheduanna (voice)

Michael Chochol

Jan Oort

Oliver Vaquer

Joseph von Fraunhofer (voice)

Fred Tatasciore

Democritus (voice)

Larry Cedar

Nick Jameson

Michael McConnohie

Masasa Moyo

Maria Frucci

Martin Jarvis

Humphry Davy (voice)

Noah Langford

(voice)

Fay Masterson

(voice)

Heiko Obermöller

Einstein's Father (voice)

Julian Ovenden

Michael Faraday (voice)

Jack Rainsford

(voice)

Glenn Steinbaum

Bruce Heezen (voice)

William Salyers

(voice)

Paul Sorvino

Augustin Mouchot (voice)

Eliza Schneider

(voice)

Frank Baxter

Self (archive footage)

John F. Kennedy

Self (voice) (archive footage)

Masoumeh Husseini

Monk (voice)

Harssh A. Singh

Ashoka (voice)

Nick Sagan

Clinnette Minnis

Shereen Balles

Female Voyager (voice)

Kapeneta Te'o-Tafiti

Male Voyager (voice)

Joseph Grange

John Herschel (voice)

Carol Bach Rita

Caroline Herschel (voice)

Viggo Mortensen

Nikolai Vavilov (voice)

Ken Lally

(voice)

Phil Crowley

(voice)

Yuri Lowenthal

(voice)

Edita Brychta

(voice)

Christopher Lee Parson

(voice)

Andrew Pifko

(voice)

Brendan Bradley

(voice)

Matthew Jayson Cwern

(voice)

Alan Shearman

(voice)

Natasha Goubskaya

(voice)

Skye Sammoutis

(voice)

Marcelo Tubert

(voice)

Mara Junot

(voice)

Rick Pasqualone

(voice)

Elijah Braik

(voice)

Novi Brown

(voice)

Jamie Hanes

Will Greenburg

John Goodricke

Dex de Groot

Joep Fellinger

Steve Oatway

Charles Darwin

Adam Tsekhman

Christiaan Huygens

Neil Arnote

Neil Armstrong

Ernie Vigil

Thomas Young

Judd Hirsch

Robert Oppenheimer (voice)

Olivia D'Abo

Marie Curie (voice)

Yurika Okamura

(voice)

Selyna Chan

(voice)

Sianna Chan

(voice)

Joseph J. Micucci

Young Father

Lennard Ortmann

Albert Einstein

Alex Bartram

Samuel Sagan

Brannon Braga

World's Fair Attendee

Marcello Guedes

Young Neil deGrasse Tyson

Leandro Guedes

Young Stephen Joseph Tyson