David Attenborough

Self - Narrator (archive sound)

Sean Carroll

Self - Narrator (archive sound)

Craig Childs

Self - Narrator (archive sound)

Brian Cox

Self - Narrator (archive sound)

Alex Filippenko

Self - Narrator (archive sound)

Stephen Hawking

Self - Narrator (archive sound)

Michio Kaku

Self - Narrator (archive sound)

Lawrence Krauss

Self - Narrator (archive sound)

Janna Levin

Self - Narrator (archive sound)

Phil Plait

Self - Narrator (archive sound)

Martin Rees

Self - Narrator (archive sound)

Mike Rowe

Self - Narrator (archive sound)

Michelle Thaller

Self - Narrator (archive sound)

Neil deGrasse Tyson

Self - Narrator (archive sound)