NEIL DeGRASSE TYSON

AGE: 49
OCCUPATION: Astrophysicist, author, director of the American Museum of Natural History's Hayden Planetarium and host of PBS's NOVA scienceNOW
NUMBER OF TIME COVERS: 0
PREVIOUS APPEARANCES ON THE TIME 100: 1

PRO: In a funny, genial voice, Tyson's best seller, Death By Black Hole, opened up the scientific community's understanding of the universe to the average Earthling.

CON: A black hole could open up and consume Tyson at any moment. Who's laughing now? Black holes are nothing to joke about.