The quantum accelerator, a.k.a. the Aronov device, was previously seen in the series premiere.
The title comes from a monologue from William Shakespeare's Macbeth, Act 5, Scene 5. "She should have died hereafter; there would have been a time for such a word. Tomorrow and tomorrow and tomorrow creeps in this petty pace from day to day, to the last syllable of recorded time; and all our yesterdays have lighted fools the way to dusty death." A line from the same passage provided the title of All Our Yesterdays (1969), which also involves a time-displaced romance.
In Kelly's apartment, seven years ago, the picture hanging on the wall is the album cover of "Escape" by Journey.
The rainbow drinks that Kelly and Claire are drinking are - according to some recipes - a drink called a Pousse Cafe.
Ed begins the season by engaging in a romantic relationship with Lt. Tyler and ends it pursuing a romantic relationship with the younger version of Kelly. Both his romantic interests for the season are blonde lieutenants in science division (green uniform with atomic-symbol patch) who shouldn't be on his ship.