Huh. So how does Cooper know at what age to send the message to her? Is that where the love element comes into play, where they're just communicating through emotional instinct rather than gravity? Like, if Cooper can see Murph at every age inside the tesseract, what if he tries sending it to her at an age where she doesn't give a ****? Why does it happen to be the one moment where she's older and she decides to go back to the house?
^ That wasn't being humorous, by the way - I'm genuinely curious about this, because it's by far my favorite sequence in the entire movie, maybe in all of Nolan's movies, and I absolutely love how I don't fully understand it.