The Biggest Unanswered Questions In Interstellar

At the beginning of Interstellar, Cooper's two children Murph (Mackenzie Foy) and Tom (Timothée Chalamet) function as pretty typical siblings, neither best friends nor mortal enemies, but simply two kids who mostly get along and occasionally get under each other's skin. Even the fact that Cooper clearly seems to favor Murph over Tom doesn't really seem to be a source of bad blood between any of the family members, even if it probably should be.

All that changes, though, when Cooper leaves aboard the Endurance. Murph spends the next few decades nursing a grudge against her father, while Tom does his best to remain in touch, even long after Cooper stops responding thanks to the 23 years he loses on the water planet. During that time, Tom (Casey Affleck) marries and has two children, although his oldest dies a few years later of complications due to the dust-saturated atmosphere. Murph, meanwhile, throws herself into her work with Professor Brand and rarely visits home, but eventually returns to try to convince Tom to move his family out of their old farmhouse and underground with her. When Tom refuses, Murph decides to trick him, luring him away so she can essentially kidnap his family.

She doesn't actually manage to leave before Tom returns, and by then she's realized she has what she needs to solve the gravity equation and save humanity, but while Murph gives her brother a relieved hug upon his return, Tom doesn't look nearly as ready to bury the hatchet. Despite Murph's great accomplishment for humanity, the actions she took with her brother's family significantly overshot the boundaries he'd set. But we never see Tom again after that, making us wonder if the end justified the means for him, or whether Murph's actions damaged their relationship permanently.