Tyson, Neil deGrasse
From The Big Bang Theory Wiki
Neil deGrasse Tyson (born October 5, 1958) is an American astrophysicist, science communicator, the Frederick P. Rose Director of the Hayden Planetarium at the Rose Center for Earth and Space, and a Research Associate in the Department of Astrophysics at the American Museum of Natural History. Since 2006, he has hosted PBS's educational television show NOVA scienceNOW. He has been a frequent guest on The Daily Show, The Colbert Report and Jeopardy! (from Wikipedia).
Dr Tyson appears as himself, chatting with Raj in the corridor at Caltech. Raj introduces Dr Tyson to Sheldon, who dismisses him out of hand due to Tyson's involvement with the "demotion" of Pluto] to minor planet status.
