Issues with time-bubble powers in era 2

[darkkpane]

So I've been reading Mistborn Era 2, and found a big problem with the bendalloy allomantic power. So the power is greatly increasing time flow in a bubble by burning the metal. I had no issues with that, until a scene where Wax falls out of one. He only describes a slight discomfort doing it. This makes no sense if you look at the actual physics of how that would work, and since Brandon and this community are generally interested in integrating "realistic" physics into these worlds with magic, I thought I would share my thoughts. So the biggest problem is that you should absolutely not want to move in or out of the time bubble. You might've heard of a phenomenon regarding black holes called "spaghettification". Since black holes have such a great gravitational pull, if any part of your body is closer to the singularity than another (which would always happen), you get stretched out by the differing pull on your, let's say feet, compared to your upper body. Essentially, by moving out of the bubble, a reverse spaghettification effect would happen to you. Since time flows slower on the outside, the part of you out of the bubble would also move much slower, while the part of you inside much faster. I think this would compress your body to an extreme degree, maiming, or in the worst case, killing you in the process. 

What are your thoughts on this? I just wanted to share my opinion, because it nagged at me. I'm not very far into the books, so there might be an explanation for it later on. If so, hit me with a RAFO

[therunner he/him]

A good question, and one we have answer to (unless Brandon changed his mind later, as in another later WoB he RAFOed it).
Basically, anything living touching the bubble is fully affected, so as long as part of body is inside the bubble the whole body is affected, and then it stops immediately once nothing touches the bubble.

Relevant WoBs

Quote

Klokkan

Hello Mr. Sanderson, I have a question about bendalloy bubbles—what happens to a human that is partially in and partially out of the bubble when it's placed? Does the difference in the flow of time kill him?

And, if yes, is the boundary of active bendalloy bubble effectively impassable for living organisms? I get that bullets shot out of the bubble randomly change directions, but what happens to, let's say, a person trying to jump out of the bubble (or, given enough time, a person trying to get inside)?

Brandon Sanderson

Any living thing touching the bubble is affected by the bubble.

Footnote: Original question has been deleted from Reddit in the interim
/r/fantasy AMA 2013 (April 15, 2013)

 

Quote

vorpal_username

I've been rereading alloy of law and I was wondering about a few things related to speed bubbles.

1. Speed bubbles can't move once they're put up, but what happens if you put one up while you're in a moving train or something? Does it move with the train? What if the train stops/turns while the bubble is up? (This might have happened and I'm forgetting in which case just ignore me...)

2. Can an allomancer leave their bubble while it is still up (meaning it stays up with them outside of it)?

3. What happens to things and or people partially inside of the bubble? Like, if I swing a pole through the time bubble, do I feel extra resistance or acceleration on it? If I stick my hand through it does it get all messed up like in that episode of TNG(S6E25)?

4. Is the magnitude effect that causes bullets to go off course when entering a speed bubble proportional to the slowing/speeding of time in the bubble? For example, could I put up a very slight speed bubble (gaining me an extra second every few minutes) and get the same deflection as the ones used by Wane in the books?

5. If you change your weight with feruchemy, is momentum conserved? For example, if I am moving while I decrease my weight, do I start going faster?

Brandon Sanderson

You'd be surprised by how many of these questions I answer in the next two Mistborn books. I think I might have addressed every one except number four. (In that case, the deflection is indeed proportional.) This is a RAFO, but more a "I took all this time to explain it in the text, so let's let you read it there."

/r/books AMA 2015 (June 19, 2015)

 

[darkkpane]

I see! That does indeed save a lot of trouble. 

Thanks for the response

[Frustration]

10 hours ago, darkkpane said:

So I've been reading Mistborn Era 2, and found a big problem with the bendalloy allomantic power. So the power is greatly increasing time flow in a bubble by burning the metal. I had no issues with that, until a scene where Wax falls out of one. He only describes a slight discomfort doing it. This makes no sense if you look at the actual physics of how that would work, and since Brandon and this community are generally interested in integrating "realistic" physics into these worlds with magic, I thought I would share my thoughts. So the biggest problem is that you should absolutely not want to move in or out of the time bubble. You might've heard of a phenomenon regarding black holes called "spaghettification". Since black holes have such a great gravitational pull, if any part of your body is closer to the singularity than another (which would always happen), you get stretched out by the differing pull on your, let's say feet, compared to your upper body. Essentially, by moving out of the bubble, a reverse spaghettification effect would happen to you. Since time flows slower on the outside, the part of you out of the bubble would also move much slower, while the part of you inside much faster. I think this would compress your body to an extreme degree, maiming, or in the worst case, killing you in the process. 

What are your thoughts on this? I just wanted to share my opinion, because it nagged at me. I'm not very far into the books, so there might be an explanation for it later on. If so, hit me with a RAFO

If I recall correctly there is a WoB that I will try to find later, that says that something is either in the bubble or not, and there is a certain point where they simply cross over.

[Halyo_Alex he/him]

42 minutes ago, Frustration said:

If I recall correctly there is a WoB that I will try to find later, that says that something is either in the bubble or not, and there is a certain point where they simply cross over.

If you want the Realmatics of it, it's when the object's Cognitive center of "mass" aka the Center of Self is in or out of the object, I believe.

[Returned he/him]

48 minutes ago, Frustration said:

If I recall correctly there is a WoB that I will try to find later, that says that something is either in the bubble or not, and there is a certain point where they simply cross over.

It seems like there is still some transition at some point. If not, we wouldn't see effects like bullet deflection. But there could be other reasons for those sorts of effects.

But more broadly there is some point at which reality as we know it breaks to allow for magic at all, and since the magic itself covers that break we could also just extend it to cover any transitions as well.

[Lego Mistborn he/him]

1 hour ago, Returned said:

It seems like there is still some transition at some point. If not, we wouldn't see effects like bullet deflection. But there could be other reasons for those sorts of effects.

But more broadly there is some point at which reality as we know it breaks to allow for magic at all, and since the magic itself covers that break we could also just extend it to cover any transitions as well.

There is some transition, when it suddenly changes from "in" to "out", which is what results in the "deflection"

[Quantus he/him]

2 hours ago, Frustration said:

If I recall correctly there is a WoB that I will try to find later, that says that something is either in the bubble or not, and there is a certain point where they simply cross over.

This one?

 

Quote

 

Kurkistan

If you are standing inside of a time bubble, and throw a spear out of the bubble, what happens to that spear as it traverses the border of the bubble? Are different parts of the spear ever in different "time zones," going fundamentally different speeds?

On that line of reasoning, what would happen to a train and its occupants if Marasi stood next to railroad tracks holding up a Cadmium bubble while that train sped by?

Brandon Sanderson

In general, a large object going through a time bubble is not going to notice. An object is either in or out, and it depends in part on how the object views itself. People inside the train would be inside of its influence, and wouldn't notice the bubble. The spear would go from one to the other, but would never be in both.

17th Shard Forum Q&A (Sept. 26, 2012)

 

 

[Returned he/him]

52 minutes ago, Ta'veren Kaladin said:

There is some transition, when it suddenly changes from "in" to "out", which is what results in the "deflection"

Right, obviously. What I was trying to get across is that it's not clear to me why that would cause a deflection: a bullet is in one frame of reference at point A, and then is in a totally different frame of reference at point B, and neither point has different properties local to the bullet. It's not like the bullet is in air at point A and suddenly in water at point B. If the transition is instantaneous (the bullet is 100% in and then 100% out with no transition state) what is it that's causing the deflection? Is it all wind shear or something?
 

I imagine this has been touched on elsewhere, but if I've come across it I don't remember it so I apologize if we're re-treading well-trod ground.

[offer]

9 minutes ago, Returned said:

Right, obviously. What I was trying to get across is that it's not clear to me why that would cause a deflection: a bullet is in one frame of reference at point A, and then is in a totally different frame of reference at point B, and neither point has different properties local to the bullet. It's not like the bullet is in air at point A and suddenly in water at point B. If the transition is instantaneous (the bullet is 100% in and then 100% out with no transition state) what is it that's causing the deflection? Is it all wind shear or something?
 

I imagine this has been touched on elsewhere, but if I've come across it I don't remember it so I apologize if we're re-treading well-trod ground.

The bullet does have different property inside and outside - its speed. Because of preservation of mumentum it changes its direction. There is preservation of mumentum only in the direction tangential to the "barrier" because there is a force acting on the bullet in the direction of the barrier. It is the same phenomenon that causes diffraction of light when it passes from air to water (https://en.wikipedia.org/wiki/Snell's_law).

 

I believe that the reason its direction seems random is that the barrier is actually very rough and the tangential direction relative to the barrier depend greatly on where exactly the bullet hit the barrier.

[Returned he/him]

40 minutes ago, offer said:

The bullet does have different property inside and outside - its speed. Because of preservation of mumentum it changes its direction. There is preservation of mumentum only in the direction tangential to the "barrier" because there is a force acting on the bullet in the direction of the barrier. It is the same phenomenon that causes diffraction of light when it passes from air to water (https://en.wikipedia.org/wiki/Snell's_law).

I'm not sure I follow how those apply to the speed bubble situation (which is likely a failing of mine, not of your explanation). I don't see that the velocity of the bullet would change from one side of the bubble to the other, because since the transition is instantaneous and complete the bullet is always 100% in local time from its own frame of reference.

More concretely, I'm thinking of the situation this way:

In the bubble a bullet of some arbitrary mass is fired and might be going at 1700 miles per hour (sped-up time compared with most of the world, as we're in the bubble), which would appear far faster to an observer outside of the bubble and normal to an observer within. The bullet then hits a decisive point in the bubble's surface and is immediately 100% outside of the bubble, and at that time it's still going at 1700 miles per hour (regular time with regard to the world), which would seem far slower to someone observing from inside the bubble. The "sped up" properties from being inside of the bubble immediately and completely cease to apply once the bullet leaves, and the media are the same on both sides of the bubble except for the arbitrary difference in rate of passage of time.

From the bullet's perspective nothing changes at any point, and it's always going at 1700 miles per hour through the air. It should be, to my understanding, no different than the speed bubble dropping after the bullet is fired but before it reaches the bubble's edge. I'm not sure we've seen or heard of any such experiment in the books though, so maybe it isn't!

It doesn't seem like the surface of the bubble itself has any refractive properties (that I recall, at least). We don't see visual distortions (like viewing through the surface of a liquid), or red or blue shifts (though the characters that we'd need to notice them in order for us to read that are probably unaware of what they'd need to make note of), and from the outside of a bubble you can view things on the far side of the bubble through the bubble itself without any effect.

I may still be missing the relevant elements, but please don't feel pressure to write out fuller explanations if you don't already want to. The relevant pieces may be too far outside of my expertise to grasp without a lot of study, and I'm comfortable just calling all of the seeming discrepancies "magic" and letting that be the full explanation. Certainly unless and until there is a scenario in one of the books that fixes an additional property into the official rules of speed bubbles.

Since Cosmere magical effects themselves are arbitrary I strongly suspect that at least some of their limitations are also arbitrary. This one might be primarily narrative. If bullets didn't deflect from a Bendalloy bubble then gunfights against Wax and Wayne would be pretty unexciting. They'd just be sniper-style executions of every adversary over the course of very little ordinary time, while Wax and Wayne are never in much danger or even hard-pressed.

We can read all kinds of extensions into whatever arbitrary rules we've seen, but I don't think that trying to do the reverse is especially reliable. There isn't much that "should" happen when interacting with a speed bubble because speed bubbles are already explicitly, magically unreal.

[Frustration]

On 8/15/2022 at 2:26 PM, Quantus said:

This one?

 

 

Yep, thank you.