Okay, so I've been seeing the critique of Ryland not balancing the tubes prior to the Life is Reason sequence, and I have a genuine question.
Does the fact that the ship itself is making gravity by spinning change things?
As a lay person, that didn't throw me off as much since:
a) When the Hail Mary and Rocky's ship link up, it seems like that Ryland may have adjusted the Centrifugal settings of the Hail Mary based on the way he responds to Mary - "It is not advised to modify the centrifugal settings of the ship" or something like that.
b) They can only use the equipment when the gravity on the Hail Mary is active.
In my mind, I was figuring with the slightly heavier gravity in the Hail Mary that Ryland placing the tubes like that was him trying to counteract the slightly heavier gravity and centrifugal spin from the ship itself.
I'm honestly really curious.
Hi, excellent question! I'll do my best to answer, but I'm no physicist so take what I say with a grain of salt
Short answer is I don't think adjusting the artificial gravity would have any effect on the centrifuge. The whole point of a centrifuge is it spins super fast to generate an outward force on the object, working against said object's inertia. Basically the object wants to move in a straight line, and in fighting against the spinning a sort of pseudo-force is generated/enacted on that object. Now, in order to keep the object from pulling the wheel too much on one side, you need something of equal mass on the other side to keep the machine balanced. For something spinning at slower speeds, not much force is being generated, so it doesn't matter all that much. But!!! Once you start using faster speeds, even as low as 300 rotations per minute, balancing becomes crucial! The artificial gravity wouldn't change the need for balancing because the reference point in the centrifuge is the sample itself, gravity outside the system doesn't matter bc the machine is essentially enacting its own gravitational force on the samples, completely separate from the outside environment!
Even if the gravity in the Hail Mary was slightly stronger than Earth's gravitational pull, it shouldn't have any sway on how the centrifuge functions. I think the reason Grace needed gravity to use the lab was to keep all of the equipment from flying around, since if there's no downwards gravity acting on the centrifuge, then one, whatever you're trying to separate out of suspension isnt going to stay separated due to lack of gravity once the tube is removed from the centrifuge, and two, there's nothing keeping the centrifuge in place once it starts spinning, meaning it could fly off in whichever direction the second the system becomes unbalanced.
Also to address the first part of your question, I think the reason Grace adjusted the gravity settings was to ensure both his and Rocky's ships were spinning at the same rate so that they could attach. This would have a momentary effect on gravity inside the ship, probably similar to those carnival rides that spin so fast your body sticks in place against the ride, but overall it was just to make sure both ships were in proper alignment for contact.
It's possible the centrifuge used in the scene (in the reality of the film, not the prop itself) was spinning at such a slow rate that it didn't matter that much, but I doubt that's the case if he was trying to separate out cells from a liquid suspension. In my experience, you need at least 300 x g (300 times Earth's gravity, measured in "g's") to pellet down mammalian cells from growth media, and that's mostly because mammalian cells are huge and dense as FUCK. If he was trying to concentrate what are essentially bacteria-sized cells, Grace would've needed at least 1000 times more than 300 x g, and even with mammalian cells you still need to balance the samples.
If i were doing the same experiment Grace was, and assuming both tubes contained roughly the same mass/volume, I would have placed one tube directly across from the other on the wheel instead of side-by-side.
I hope that made some sense! Apologies if it seems a tad unclear, just let me know if you have any followup questions!
