Hi! I'm writing a (completely non-professional) superhero story; one of my characters is a speedster with the ability to 'shift' into a different frame of reference in regards to time. When she does this, the world slows down from her POV -- but she can output the same amount of momentum (from everyone else's POV, though, her momentum becomes massive). In her world, everything is very fragile; in our world, she is ridiculously durable, fast, and strong. I've already spoken to some incredibly helpful people about this idea (one person suggested using a vectorless kinematic model), and I've gotten some great feedback -- but I wanted to get more opinions from people who understand physics, to help me wrap my brain around this. I want to portray her power in a way that's respectful toward physics; rather than using it as a sloppy ex deus machina ('vibrating particles!'), I want her to use her power and knowledge of physics to solve problems in ways that actually make sense. Meanwhile, I'm trying to get a baseline understanding of physics, so I can build a model in my head of how her power works and what its consequences are. PS: She's a teenager who goes by 'Shift' -- she uses rollerblades while speeding around -- and her archnemesis is the Professor, another speeder who is also an astrophysicist. He uses physics for *EVIL*. Some of the points that have been brought up so far, and issues I'm trying to understand: * If she's actually dilating time, she's going to be seeing in a different visual spectrum (since visible light will no longer be at a 'frequency' she can perceive). However, in the kinematic model suggested by someone else, this isn't an issue (since the doppler effect is vector-based!). That being said, even in this model, less photons will reach her eyes, which means that when she 'shifts', things will get darker. * I've been struggling with the issue of the Armstrong limit -- because if she treats air particles as if they have less momentum, that translates to less *pressure*, which means she might not even be able to *breathe*. However, it's been pointed out that under a vectorless kinematic model, since she'd be treated as having increased density -- and air pressure isn't an elastic collision -- it would actually equal out. * Even *if* air pressure isn't a concern, though, when she shifts, I'm still struggling to understand how breathing will work! * She can probably jump really, really high when she's shifted (because of her momentum increase). But she'll probably also leave craters in her footsteps if she's not careful. Any and all feedback is appreciated. I'm also consuming resources to get a grasp on basic physics so I can figure out the answer to some of these issues myself (Khan Academy has been very helpful). Thank you for reading!