Could an iron compounder make a black hole?

[dstokes7]

My question is twofold. First, as I understand compounding on Scadrial, an iron compounder could store weight in their metalminds, then burn them to draw forth greatly amplified weight. My first question, then, is could an individual store weight in a metalmind, then while burning it, funnel all that multiplied weight directly into new metalminds that could then be burned to amplify it further?

If so, then here's my second question. My understanding of the ferruchemical weight power is that it doesn't increase a person's mass, it increases gravity's pull on the person. With that in mind, could such a compounder store up vast quantities of compounded weight in his metalminds, then tap it all at once to increase gravity on himself so much that he became a pseudo-singularity at the heart of a black hole? Or maybe generate a wormhole (maybe that's how Scadrians do FTL in the space age)? Such a thing might even allow these people to investigate black holes from the inside, since the power also increases the ferruchemist's strength enough to support their increased weight (and hence the user could actually survive the black hole they made). Am I completely off base here, or would that be possible?

[Through the Living Hopper He/Him]

Yes, they can multiply it like that. One could say that they compound their weight.

No, because it stores up gravity's pull on them, not their gravitational pull. They could do weird stuff, but without increasing mass, a black hole can't be created. I think that there are a bunch of topics about this, too, and they have some pretty good discussions.

[alder24]

On 4/25/2025 at 8:30 PM, dstokes7 said:

My question is twofold. First, as I understand compounding on Scadrial, an iron compounder could store weight in their metalminds, then burn them to draw forth greatly amplified weight. My first question, then, is could an individual store weight in a metalmind, then while burning it, funnel all that multiplied weight directly into new metalminds that could then be burned to amplify it further?

If so, then here's my second question. My understanding of the ferruchemical weight power is that it doesn't increase a person's mass, it increases gravity's pull on the person. With that in mind, could such a compounder store up vast quantities of compounded weight in his metalminds, then tap it all at once to increase gravity on himself so much that he became a pseudo-singularity at the heart of a black hole? Or maybe generate a wormhole (maybe that's how Scadrians do FTL in the space age)? Such a thing might even allow these people to investigate black holes from the inside, since the power also increases the ferruchemist's strength enough to support their increased weight (and hence the user could actually survive the black hole they made). Am I completely off base here, or would that be possible?

F-Iron stores mainly mass but it's weird as it doesn't follow normal rules. And yes, that's how compounding work.

Practically speaking, you probably won't be able to burn through enough iron to generate mass required to create a black hole. That would be a whole lot of iron. A black hole with a radius of 10 cm would have a mass of more than 11 Earths. That's just a ridiculous amount of mass you would need to create via compounding, you would just run out of both iron and your lifetime before getting even remotely close to that value (compounding isn't instant, burning metalminds takes time just as burning regular metals does). And that's just a 10 cm radius, a black hole with a radius of 1 meter would need more than 100 Earth's masses. You would probably be killed in dozen different ways by trying to tap such an amount of mass before you would become a black hole. 

But hypothetically speaking, if you have access to infinite investiture and healing, you could become a black hole (as you can become a star). But that's purely hypothetical, infinite investiture breaks the rules.

Spoiler

Questioner

Does Iron store mass or weight?

Brandon Sanderson

Excellent question. The thing is it really does involve mass, but I’m breaking some physics rules, basically. I have to break a number of physics rules in order to make Magic work in the first place. Those whole laws of Thermodynamics, I’m like “You are my bane!” (laughter) But I try to work within the framework, and I have reasonings built up for myself, and some of them have to be kind of arbitrary. But the thing is, it does store mass if you look at how it interacts, but when a Feruchemist punches someone, you’re not having a mass transference of a 1000 pounds transferring the mass into someone else.

So there are a few little tweaks. You can go talk to Peter, because Peter has the actual math. Oh Peter’s back there. Peter is dressed up as Allomancer Jak from the broadsheet. In fact we’re giving some out broadsheets, aren’t we Peter. So when you come through the line, we’re giving out Broadsheets. Please don’t take fifty—I think we might have enough for everybody. The broadsheets are the newspaper from the Alloy of Law time. It’s an inworld newspaper. It’s actually reproduced in the book in four different pages, and we put it together in one big broadsheet.

So anyway, you can talk with him, he’s got more of the math of it. I explained the concept to Peter and he’s better with the actual math, so he said “We’ll figure it out.”

Alloy of Law release party (Nov. 7, 2011)

 

Spoiler

Questioner

If a Full Twinborn (regardless of natural or holding the Bands of Mourning) had access to unlimited Investiture, could they become the sun by infinitely increasing their gravity and heat?

Brotherwise Games

Infinite Investiture, you’re theorizing?

Questioner

Dalinar’s next to him.

Brandon Sanderson

Dalinar’s not gonna be able to provide enough. But in a thought experiment, sort of outside bounds of time and space… you are providing infinite Investiture, you are providing an infinite amount of healing, and you are having them create heat and weight? The problem is, you’re gonna need a whole lot of mass to turn into the sun. I mean, there is a way you can do this, but you’re gonna have to provide… Either the Investiture’s gonna have to become mass, or you’re gonna have to have them do it in the proximity of a whole bunch of mass to have to start causing that sort of fusion reaction where the different layers collapsing in toward the center, dense layers, that sort of thing. In the realm of complete hypothesis, then yes. But, of course, you an do that here with infinite energy and infinite mass, if you needed to, using mechanical means.

I guess the weird part of that question is: the person could retain consciousness through infinite healing, and that is the weird part and that is possible. Yeah.

Dragonsteel 2022 (Nov. 14, 2022)

 

[CoderDrag0n8 He/They]

2 hours ago, dstokes7 said:

My question is twofold. First, as I understand compounding on Scadrial, an iron compounder could store weight in their metalminds, then burn them to draw forth greatly amplified weight. My first question, then, is could an individual store weight in a metalmind, then while burning it, funnel all that multiplied weight directly into new metalminds that could then be burned to amplify it further?

If so, then here's my second question. My understanding of the ferruchemical weight power is that it doesn't increase a person's mass, it increases gravity's pull on the person. With that in mind, could such a compounder store up vast quantities of compounded weight in his metalminds, then tap it all at once to increase gravity on himself so much that he became a pseudo-singularity at the heart of a black hole? Or maybe generate a wormhole (maybe that's how Scadrians do FTL in the space age)? Such a thing might even allow these people to investigate black holes from the inside, since the power also increases the ferruchemist's strength enough to support their increased weight (and hence the user could actually survive the black hole they made). Am I completely off base here, or would that be possible?

1. Yes.

2. I have no idea

[-ACE- he/him]

On 4/29/2025 at 5:52 AM, alder24 said:

But hypothetically speaking, if you have access to infinite investiture and healing, you could become a black hole (as you can become a star). But that's purely hypothetical, infinite investiture breaks the rules.

Infinite does, but you can get a lot on Taldain during the day, so theoretically, if someone who had carried a dawnshard for very large amounts of time (ex: Hoid) were to spend a long time on Taldain, absorbing the sun's investiture, then theoretically, you could-over a very long time, maybe 10,000 or so years-get enough investiture to make a black hole.