Silence is Golden.

Bruce Dern's tree-hugging, robot loving, neurotic in space, is the next subject for my Seminal Sci-fi Moment.
Silent Running is perhaps the most emotional I have ever become whilst watching sci-fi.

Most of you probably know the story. On the Earth all natural plant life has become extinct and what remains is kept in enormous domes, attached to freighters which orbit Saturn. The film's subject is topical even today.
Bruce Dern's performance is truly endearing and even though his character kills the rest of his crew in order to save the animals and plants which he cultivates in the domes, no sympathy is lost for his cause. His crew members and indeed Earth Government, seem flippant and quite at ease in ordering the destruction of his lifes work and indeed the only remaining examples of specific Earth flora and fauna in (one must assume) the universe.
He then becomes a fugitive, with three robots (service drones) and a single intact dome.
The finale sees him destroying himself and one of the robots (one has also been lost earlier in the film after becoming detactched from the side of the ship whilst doing repairs) as he jettisons the last remaining dome into deep space.
Regardless of the plight of Earth's forests and wildlife, the small, mute, bipedal, ambling robots, which Bruce Dern's character (Freeman Lowell) names Huey, Duey and Louis, were the subject of my emotional focus when I first saw the film as a kid. The robot that stays behind with Lowell has been crippled by an accident, and the emotional attachment Lowell builds with these companions seemed as important to me as the fate of the forests in the dome.
The last robot is put aboard the dome so he can maitain the eco system and tend the forest.
At the end of the film, there is hope that the dome will travel, and the forest survive, being tended by the little robot, and perhaps germinate on an alien planet somewhere. But for me, as a kid, watching the final scene of a little robot, all alone, with a colourful little tin watering can wandering through the dome's forests, while the hauntingly beautiful music of Peter Schickele, sang by Joan Baez, plays in the background, something burst inside of me. I bit back tears as my father led me from the cinema. And when I just could not hold them in any longer I pretended to fall and hurt myself and burst into a flood of tears. I always enjoyed our sci-fi cinema trips so I wanted to keep my pretense of being daddy's stoic little boy and never told him the truth about why I cried for an hour after watching Silent Running. Of course mum could tell something was up when we got home, and I told her very secretly about the poor little robot before I went to bed... before bursting into tears again.
This has to be a very tearful Seminal Sci-fi Moment No.3