We all know it’s been 14 billion years since our universe was in a hot dense state and expansion started — but we’re having trouble believing it’s been nearly a decade since The Big Bang Theory premiered back in 2007!

And while it’s been incredible seeing the actors change — and the characters mature — on our TVs every week, it’s equally amazing to see their transformations in front of our very eyes!

Scroll through the gallery to see what the stars of BBT looked like in season 1 compared to what they look like today!