The most well-known concept in Lightyear is time dilation. Buzz is attempting to bring his team back to Earth after crash-landing on an uncharted planet, but to do so he must achieve hyperspeed. He makes several test runs with different fuel combinations, but fails every time. And there’s a catch – every minute spent in hyperspeed equals a year on the planet, meaning Buzz’s crew will age significantly by the time he finally succeeds.
Time dilation is related to Albert Einstein’s special theory of relativity and states that “time moves relative to the observer. …when an object is moving very quickly it experiences time more slowly than when it is at rest” (via Space). Therefore, time passes much more slowly for those on the planet’s surface than for Buzz while in hyperspeed.
“Well, notice that in this sci-fi universe, the ‘sci-fi’ is with a lowercase ‘s’ and a capital ‘F,'” said producer Galyn Susman in an interview with the AV Club. “But apart from [NASA has] Speaking of her collaboration with NASA’s Thomas Marshburn, director Angus MacLane said, “Obviously we took a lot of liberties… but there’s a lot of truth to it. and [Marshburn] tried to explain the science of time dilation to us with many different examples. And we — okay, I — haven’t really figured it out.”
Pixar artists cannot be expected to be rocket scientists, and their films will always draw on what makes for the best dramatic scenarios. But it’s also clear that they’ve put mountains of effort into their research that really takes their films to infinity and beyond.