#ik this is nerdy as hell but the SCIENCE

[scaramint]

On Chuuya’s Gravity Manipulation

So I’ve been thinking about For The Tainted Sorrow instead of studying for my physics exam bc thinking abt gravity is just so much more fun than doing math abt gravity but hear me out.

Since this is obviously a fictional show about dead authors who have nothing to do with gravitational physics, this is all unnecessary; he can kick ass bc he’s cool and we can leave it at that. BUT I'm going to dissect Chuuya’s ability and see what he does to actually manipulate gravity.

Let’s take a look at For The Tainted Sorrow through classical physics first with Newton’s Law of Gravitation. This is the theory I'm most familiar with, although I would like to someday do an analysis through the lens of General Relativity.

[picture from Kleppner and Kolenkow, Introduction to Mechanics, 3rd Edition]

Basically, the gravitational force that anything can exert on something else is proportional to its mass and varies inversely with the square of the distance, and it is always attractive (towards the force center) Now, Chuuya's ability is to manipulate gravity, so he can change what this force is.

We aren’t given much on the principles of how he changes it so let's say that the general relation remains the same.

Assuming that the general form of the force does not change, he can manipulate the force in different ways

He can change the mass of his own body or the target to increase force.

He can change the distance from his body to the target 

He can change the relation from an inverse square law to something else

He can change the value of G (the gravitational constant)

Now,

Mass is a fundamental quantity (for our level of analysis) so I don't think it's practical that Chuuya can manipulate mass

We know that Chuuya's ability has a range and activates on touch so he does not have any control over the distance r

Changing the power of r does not seem to have as strong effects as Chuuya's gravity manipulation shows. Take a look at these graphs

[graphed on desmos]

We can immediately rule out Graph 3 because we know Chuuya has a range. Graphs 2 and 4 are similar enough to Graph 1 that I think there is not enough cause to take them instead of the standard inverse square law. I will have to do some calculations to understand how gravity would work in these wacky potentials, so that'll be a different post, I guess.

One problem I have with this theory is that Chuuya may appear to have a ranged ability, but as far as I know, it activates on touch (correct me if I'm wrong) so manipulating fields of gravitational potential does not seem to be his modus operandi.

He can change the value of G (the gravitational constant)

Now, this is my pet theory because it explains how Chuuya's ability affects only the objects he chooses to use his ability on instead of a general gravitational field around him.

The gravitational constant is really small in our universe and is restricted to a very narrow range. Any deviation from this will cause a lot of problems for the universe as we know it. But, since Chuuya only affects the gravity of things he touches, I don't think his ability will have any lasting effects. This manipulation of G can directly explain how he dramatically changes the magnitude of the momentum of any object he interacts with.

To see the power of this, let's take our friend g, the acceleration due to gravity.

[once again from K&K, 3rd]

g here is acceleration, so we can see that changing G even a little can dramatically change how fast things move. Chuuya's ability is best described by flashy movements and incredible speed which can be explained by the change in acceleration of the objects he touches and him using his ability on himself.

One more important thing about Chuuya's ability is that it can affect the direction that gravity is working. The minus sign in front of the force equation at the beginning of this post indicates that gravity is an attractive force i.e. it always works towards the bodies and pulls them together. Except we see Chuuya use gravity as much more than just an attractive force.

He reverses the direction of momentum of bullets in the GSS fight scene in the Fifteen arc. 

He regularly walks on walls and ceilings.

He accelerates bullets away from him with his ability in his encounter with the Hunting Dogs.

It would be easy if this was the only thing he could do, as we can amend our argument to include that he can change the sign of G as well to accommodate for this repulsive action.

However, the problem is that his ability does not work only linearly. He can change the trajectories of bullets mid-flight and has a borderline telekinetic level of control of his ability. This cannot be explained with sign changes alone, and there must be something funny going on with the direction vector of the force. I don't think this can be explained with Newtonian Mechanics alone so I am going to shelf this here until I can come up with a different formulation for it.

Of course, none of this applies to Corruption. I think that has to be done exclusively through GenRel so that's a little later on the schedule.

#nakahara chuuya #bsd #bsd analysis #bsd headcanons #bsd chuuya #physics #physics chuuya #ik this is nerdy as hell but the SCIENCE #physics isnt scary yall are just mean #give chuuya a doctorate 2023 #min infodumps #bungou stray dogs