It is common for sitcom pilots to run a little longer to establish characters and the setting, and The Big Bang Theory is no exception.
If you are wondering why some episodes of The Big Bang Theory (TBBT) feel like they end in the blink of an eye, you aren't imagining it. While the show occupies a standard 30-minute television slot, the actual content length is much shorter. big bang theory episode length
You might wonder why a show with such complex dialogue (referencing string theory, Klingon, and comic book lore) keeps things so short. It is common for sitcom pilots to run
If you are looking for "hour-long" episodes, they do exist, but they are essentially two-parters fused together. For example: they do exist