
Narrator
Mike Rowe

Himself - Narrator / Self - Narrator
Erik Dellums

Self - Theoretical Physicist
Lawrence Krauss

Self - Theoretical Physicist
Michio Kaku

Herself
Michelle Thaller

Self - Astronomer
Phil Plait

Himself - Narrator
Richard Lintern

Stephen Hawking

Self - Astronomer
Andrea Ghez

Self - Astronomer
Shep Doeleman