Guest Stars Grant Tremblay as Himself (Astrophysicist) Amber Straughn as Herself (Astrophysicist) Alex Filippenko as Himself (Astrophysicist) Max Tegmark as Himself (Theoretical Physicist) Sean Carroll as Himself (Theoretical Physicist) Clifford V. Johnson as Himself (Theoretical Physicist) Katherine Freese as Herself (Cosmologist) Carlos Frenk as Himself (Cosmologist)
