Search the Community

Inspired by discussions on these threads: https://www.17thshard.com/forum/topic/109284-perfect-gemstones/ https://www.17thshard.com/forum/topic/109181-air-travel-on-roshar/, I've been thinking about how much power (in the sense of physical energy over time) can be drawn from Investiture (especially in cases where it isn't end-positive - new Investiture isn't being drawn in - but the Investiture is just "sitting there" powering something, like Stormlight in a light source or Breath in a Lifeless or Hemalurgic spikes in a person or creature). While these are all extremely rough order-of-magnitude estimates, I think there's some that can be at least roughly quantified. (I have no idea how to quantify using Iron Feruchemy to power a perpetual motion machine.) Stormlight as a light source While Surgebinding might be end-positive, using Stormlight in spheres/gems for illumination seems end-neutral (ish: it's not exactly a 'magic system'). As pointed out on the Perfect Gemstones thread, while generally the Stormlight leaks out of the gemstone, it isn't really being "used up" or converted to energy. The loss of Stormlight is just leakage due to flaws in the gemstone - since perfect gems don't lose Stormlight but still glow. A mark glows 'almost as bright as a candle' and a broam 'with the light of several candles'. As Stormlight lighting doesn't emit heat, unlike actual candles which output most of their energy as heat, this is much less than 1 watt per broam of Stormlight. Awakening Awakening is end-neutral, but Breath can provide physical energy: Lifeless and Awakened objects don't need to eat to expend energy. Vasher's Law of Comparability states that " The amount of Breath required to Awaken something isn't necessarily indicative of its power once Awakened", so there's not going to be a simple "1 Breath = x watts" equivalence. But the most Breath-efficient Awakening is a Lifeless, since it's the nearest to a human form. Lifeless don't really seem superhumanly strong, so probably roughly equivalent to a human... approximate human power output is a few hundred watts, so roughly a few hundred watts for 1 Breath. The open question here is non-human Lifeless. Vasher can awaken a squirrel Lifeless for 1 Breath, but it is much smaller and weaker than a human. Would Awakening a horse or elephant Lifeless still cost 1 Breath? Hemalurgy Hemalurgy is actually end-negative, but it still apparently can provide physical energy. Koloss don't need to eat normal food, and yet they're far stronger than a normal human. The Kandra Blessing of Potency, which is basically the same thing as koloss spikes, gives extra strength to each muscle "More than doubled" - probably each spike adds somewhat less than one human-equivalent strength (due to Hemalurgic decay), so for a human-size kandra, the strength is between 2x and 3x normal. So by that principle a koloss's baseline strength (for a human sized 'new' koloss) is probably something on the order of 4x normal human (if there was no hemalurgic decay, it would probably be 5x). So by that principle, each Hemalurgic iron spike would provide somewhat less than the few hundred watts I suggested for a Breath powering a Lifeless. But koloss continue to grow, and if they don't need to eat actual nourishing food, the Hemalurgic strength is presumably providing more power for a larger koloss. And if the kandra Blessing of Potency strengthens "each muscle", a kandra in a larger body (like TenSoon's horse form) is presumably getting more out of it. There's going to be a size limit (we're told in WOB kandra can't get to chasmfiend size) but even at horse size a Blessing of Potency is going to be providing more than a horsepower - maybe a kilowatt or so for 2 spikes? Which is pretty good, as Hemalurgic spikes don't hold much Investiture. However, while the Blessing of Potency increases endurance, it doesn't give true tirelessness like Lifeless have.

I'm a huge Stormlight Archive fan who happens to be a nuclear engineer. Perhaps it's my weird brain, but I find parallels between stormlight and atomic energy. I also find inspiration in the books for the perseverance I need when advocating for a source of energy that, like stormlight, can be used for both good and evil. I wrote a blog post about it here. I also took the time to showcase some great Stormlight fan fiction (with permission). I hope you find it interesting. Happy to answer questions or critiques here

With the recent releases from WoR has come much confusion on the nature of gravity on Roshar. This is not a new discussion, but I'm starting a new thread because my response was getting too long. As a brief introduction, there are several WoB that seem to imply that gravity has a Spiritual component. However, he has also claimed that the laws of physics work like they do in our universe. Reconciling these two ideas has lead to a great deal of confusion. In what follows, I'm going to use an important device from theoretical physics - the "toy model." These are simple models that attempt to explain the bulk of phenomenon by necessarily being incomplete. Their ultimate incorrectness (as they are too simple) is overshadowed by their usefulness, as grasping the fundamental ideas is often more important than explaining all of the nuances. As such, I am not claiming any of these models are correct, but rather I am using them to illustrate the ideas. We seek to answer two separate but distinct questions: "how" the universe behaves and "why" the universe behaves in a particular way. Despite popular opinion, physics does not claim to answer many of the "why"-type questions. Why is physics the same in all inertial reference frames? Why does the metric tensor obey Einstein's equation? Why do quantum mechanical observables correspond to Hermetian operators? However, postulating that these things are true in our universe answers many other "why" questions that are really "how" questions in disguise. Why does a superconductor expel all magnetic fields? Well, we observe them to do so, and so the question is how that arises from knowing the basic physics. Remember that this entire field is a observation-driven discipline and we only seek to model it using mathematics. I am going to make one concrete conjecture: The physical laws in the cosmere are the result of interactions between Realms. Without going too deep into general relativity, we will simply claim that "gravity" is the phenomenon of massive objects feeling an attractive force between them. Even in our universe, it it not known why this occurs (i.e why does mass bend spacetime). "Why" is not really relevant for predicting gravitational phenomenon - experiments show us that general relativity works. However, the in the cosmere, there is some underlying reason due to Spiritual interactions that this is the case. We can then rephrase the question of "why do masses attract?" as "how do Spiritual interactions generate attractive forces between masses?" The "why" question then becomes "why do Spiritual interactions happen in a particular way" which is easily answered as "Brandon set it up that way." Magic fits into this paradigm nicely. Let's look at two examples: The gravity Surge allows one to modify the direction and strength of the gravitational interaction on a massive object. Since we know that gravity is the result of some Spiritual interaction, we then understand the gravity Surge as modifying the Spiritual properties of an object which results in a change how the effective mass-mass interaction works. If we want to get slightly more technical, we could consider the following model. Imagine that gravity works as it does on earth - an effective force due to the curvature of the metric in spacetime. The metric becomes curved due to the presence of matter and energy. A quick and dirty model of the gravity Surge would involve using energy (in the form of Stormlight) to locally bend the metric tensor resulting in a change of the local gravitational field. And if the curvature of spacetime due to matter/energy is mediated through the Spiritual realm (say, energy causes the Spiritual realm to "bulge" locally and distort the Physical realm) then everything works precisely as expected. The atmospheric pressure Surge can be understood in a similar toy model. Ideal gases (and their interacting counterparts) shrink in volume when they are cooled down. The atmospheric pressure Surge then could work in the following way: the energy contained in the Stormlight is used to remove thermal energy from the air (i.e. make it colder) and thus drastically reduce the air pressure on a given surface. Then, the pressure from the atmosphere and friction would cause an object to be "stuck," much in the same way plungers can stick to a wall. To understand how this is implemented on Roshar, we might claim that the ideal gas law is a consequence of Spiritual energy investment. Heating up a gas stores energy in its Spiritual component, and this causes it to take up more room in the Physical realm. So now we understand "how" the ideal gas law works, as opposed to "why." What is the takeaway from all of this? Physics attempts to model the universe using mathematics. Whwne explaining phenomenon, we don't often consider "why" a given physical law is true. The statement that "physics is the same in the cosmere as it is on earth" means that the phenomenon obey the same sorts of mathematical relations. Why those relations are true is another question entirely. On earth, we don't know why physics is the same in all inertial reference frames. In the cosmere, there might be some Spiritual or Cognitive reason that this is the case. That doesn't, however, change the nature of the mathematical equations that describe phenomenon. What we want to understand is how the physical laws from our universe arise from the nature of the cosmere. Thanks for reading! Note: Understanding "why" laws work in our universe is actually a very interesting question when things go wrong. This is how we develop new and more complicated theories for the underlying physical laws. However, all this does is change current "why" for "how" and generate new "why." So I do not want to imply that the "why" questions are useless, only that in the cosmere this sequence terminates at "Brandon said so." Source: I'm a theoretical physicist.