I posted a simplified version of this in a tiktok comment section earlier, but honestly it deserves a longer post because honestly Rocky and Grace are both shockingly young to be on death missions.
Rocky says that he is 291 years old. He also says that the average Eridian lifespan is 689. He's roughly 42.24% through his life. If we say that this is equal to the average human lifespan (I'm saying 80y bc I'm lazy) and that he's 42.24% of the way through 80 years; Rocky developmentally is basically some 33 year old who has just spent about 6.97% (5.5 human years) of his life alone in space.
Meanwhile, Grace is somewhere in his early 40's when he wakes and meets Rocky. Assuming he's like 42, that's 6.1%ish of the Eridian lifespan making him appear in Rocky's eyes as some 5 year old that just pulled up driving his own spaceship.
This is an insane comparison but I cannot stress enough that Rocky is a 33 year old highly trained astronaut tasked with teaming up with some hyper intelligent alien that's only been alive for 5 years because the alien's kind decided to throw that 5 year old on a one way space trip just to see what happens.
Obviously this is a gross simplification of their ages and how aging works for Eridians, for all we know Eridian maturity can happen at a rate similar to cats, where there's a rapid maturation with a certain period of time rather than a consistent maturation over a lifetime.
But even with that in mind, Rocky and Grace both seem to be at a similar level of maturity where they're old enough to understand the seriousness of their situation, but young enough to still show the side of themselves that's naturally inclined to be some goofy nerd that's just overly excited to discover (friendly and intelligent) alien life.
That being said, though, if anyone’s curious about Adrian, using this kind of math to see how long Rocky's been with his mate we get 27% of his life or 21 years which would mean if they were human that they would have met when they were 12 (Even if we say humans live an average lifespan of 100 and compare that number to 689, that would still make Rocky only 15 when he meets his mate—they're childhood sweethearts!!!)
