Main Characters Astrophysicist 152 main appearances Narrator 126 main appearances Astronomer 94 main appearances Astronomer, NASA Goddard Space Flight Center 72 main appearances Planetary Scientist 27 main appearances Planetary Protection Engineer 33 main appearances Astrophysicist / Planetary Scientist, Southwest Research Institute 33 main appearances Cosmologist / Theoretical Physicist, Arizona State University 28 main appearances Planetary Scientist and Geologist 26 main appearances Theoretical Physicist, City University of New York 15 main appearances
Recurring Guest Characters Astrophysicist 117 guest appearances Astronomer 23 guest appearances Planetary Scientist 25 guest appearances Theoretical Physicist 38 guest appearances Astrobiologist 24 guest appearances Cosmologist 17 guest appearances Theoretical Astrophysicist 11 guest appearances Astronomer, Harvard-Smithsonian Center for Astrophysics 8 guest appearances Planetary Astrophysicist 7 guest appearances Particle Physicist 5 guest appearances Physicist 4 guest appearances Geologist 3 guest appearances Solar Physicist 2 guest appearances Cassini Mission Imaging Lead 2 guest appearances New Horizons Co-Investigator 2 guest appearances Cassini Mission Project Scientist 2 guest appearances Impact Specialist 1 guest appearances Solar Astronomer 1 guest appearances Aerospace Engineer 1 guest appearances Experimental Physicist 1 guest appearances ⇤ « 1 2 3 » ⇥