More than 20 years after the ’90s-era PBS series “Bill Nye the Science Guy,” the 61-year-old still wears the bow ties, and he still punctuates his speech with impassioned catchphrases. (“It’s not magic, it’s science!” is his new favorite.) But now his disheveled locks and vaguely Vulcan eyebrows are streaked with gray, and his persona has assumed a new edge. He has become more than the zany educator-entertainer who charmed kids with cartoonish sound effects. He is an activist for science, leading those now-grownups into political battle.
Of all the roles he has played, this is the one he was preparing for all along.