Steven Tyler, Jennifer Lopez, Randy Jackson

The nerds have slain the singers!

American Idol's second Season 11 outing drew 18 million viewers, down from the 21.6 million who tuned in for the season premiere on Wednesday. Fox's reality series bested The Big Bang Theory in total viewers (15.8 million), but the 100th episode of the CBS comedy scored a 5.3 in the coveted 18-49 demo, with Idol trailing at 5.2 during its first half-hour.

Overall, Idol was down 20 percent from the Wednesday telecast, and down 28 percent from last season's first Thursday airing.

8 p.m.
CBS:
The Big Bang Theory 15.82 million viewers (5.3 demo rating); Rob 11.41 million viewers (3.5)
ABC: Wipeout 5.85 million (1.8)
Fox: American Idol 18.02 million (5.7)
NBC: 30 Rock 4.05 million (1.6); Parks & Recreation 4.25 million (1.9)
CW: The Vampire Diaries 2.71 million (1.1)

9 p.m.
CBS:
Person of Interest 14.4 million viewers (3.2 demo rating)
ABC: Grey's Anatomy 9.42 million (3.5)
FOX: The Finder 6.58 million (2.2)
NBC: The Office 6.02 million (3.0); Up All Night 3.98 million (1.9)
CW: The Secret Circle 1.63 million (0.7)

10 p.m.
CBS:
The Mentalist 14.22 million viewers (3.0 demo rating)
ABC: Private Practice 6 million (2.1)
NBC: The Firm 3.42 million (0.9)