What Was That Odd 'Thud' Sound During the Debate? Listen Here

During tonight's U.S. presidential debate around 10:07 p.m. ET, a loud noise briefly interrupted the dialogue. The "thud" seemed to come from behind the stage, where the candidates were jockeying back and forth on domestic issues.

The brief moment of uncertainty did little to dissuade Republican presidential candidate Mitt Romney, who was speaking at the time. For a split-second, he acknowledged that he heard the noise, but promptly continued speaking. However, his Democratic contender, President Barack Obama, more noticeably looked behind him (and smiled) to see if he could locate where, exactly, it was coming from.

The moderator, Jim Lehrer, didn't stop the debate and nobody openly discussed what caused the noise, leaving TheBlaze -- and viewers who noticed it -- wondering what unfolded backstage.

Watch below and listen for the bizarre noise. What do you think it was? Let us know in the comments section: