The title of tonight’s episode is “The Proton Regeneration” – which is great news, because that promises another appearance by Bob Newhart as Sheldon’s childhood hero, TV science host Professor Proton. Newhart won an Emmy – his first! – for portraying the character, in what has become a sporadic but welcome recurring guest role. And it’s recurring even though the character has died, because the good professor now exists as a figment of Sheldon’s imagination. And what makes it so funny is that, even in Sheldon’s own imagination, Professor Proton is irritated by him.