We all know Bill Nye as “The Science Guy” from ’90s TV, but we’re all grown up now: Tonight, the scientist-turned-TV star will engage in a debate with Creation Museum founder Ken Ham to defend the theory of evolution. The debate, which can be watched for free online and is expected to be seen by more than 1 million Americans, was spurred when museum officials from Ham’s Creationist institution claimed that Nye hasĀ “stepped outside of observational science” by claiming that teaching creationist science in schools is bad for children. Nye, on the other hand, says that creationist views hinder science education and hopes to support evolutionism with scientific research.

Hey, speaking of evolution — yours, specifically, from ’90s kid who watched Nye to a semi-functional adult — why not look back on how rad Bill’s theme song was? If you grew up in the ’90s, chances are you learned a thing or two from this dude. Back in the day, he knew what was up with dinosaurs, electricity, the water cycle, and a whole bunch of other fun stuff. Watch this video of him teaching what evolution is and take a trip back in time.