General Relativity and Anti-investiture

[Hovestol]

All things that have energy also produce a gravitational field proportional to the amount of energy. With the time dilation in Roshar now we know that the cosmere also experiences general relativity. 

So, do you think anti-investiture gravitates normally or does it produce a negative gravitational field. In our universe nothing does anti-gravity, even anti-matter was recently confirmed to gravitate normally, but our concepts of warp drives need things that gravitate negatively. I believe there's WOB that the space-age will have FTL travel, and this seems like a good candidate for the mechanism. Either that or mass effect from weight ferochemy. 

[LeondeBowa]

So it's explained in WaT anti-investiture isn't a complete opposite of the investiture, it's just at the correct wavelength to disrupt the investiture and cause an explosion.

The thing you're asking about, I think would be possible but I don't think you'd use anti-investiture to do it

[Shatter He/Him]

But we know general relativity exists because time-dilation happens all the time in the Wax and Wayne Series as Wayne uses bendalloy to create a time bubble where time is contacted. Also, Marasi uses cadmium to create a time bubble where time is dilated. 

[LockDown Ammo he/him]

I think it is supposed to be like an anti-matter equivalent so it will have gravity normally. It is just Investiture but out of phase. So it would also cause time dilations similarly.

 

For FTL I think Brandon is going to use Spiritual Realm shenanigans as time and space don't matter there.

There were also some theories on Seons communicating via FTL but considering the delays in conversation between Shallan and Kelsier could mean that is not the case. Or it could be just that it is FTL but not instantaneous. It could also be that the communication is instantaneous and the time delay is just because of the time taken by Shallan to speak the sentence but I don't feel it accounts for it as the time dilation is roughly 8 times the Rosharan time. And Kelsier says that it takes hours for them to get it. Thats not what 8 times of a single sentence would be. Or well 16 times as it is 2 ways. It could also be that currently time dilation is lot more as the event was very recent and Kelsier said that the time dilation is slowly decreasing.

[Rhaenys She/Her]

I think anything FTL will be done with something like elsecalling or another type of portal or wormhole. The speed of light is a hard limit of the physical universe and I don't think even investiture can break the rules like that. 

[Nitpicking]

5 hours ago, Rhaenys said:

I think anything FTL will be done with something like elsecalling or another type of portal or wormhole. The speed of light is a hard limit of the physical universe and I don't think even investiture can break the rules like that. 

This is the Cosmere spoiler area, but I'm going to spoiler warn the preview chapters of Isles of the Emberdark anyway:

Spoiler

According to Isles, that is not the case. There are multiple forms of FTL, and part of that book takes place on a starship.

 

[alder24]

15 hours ago, Rhaenys said:

I think anything FTL will be done with something like elsecalling or another type of portal or wormhole. The speed of light is a hard limit of the physical universe and I don't think even investiture can break the rules like that. 

FTL is built into Allomancy and it most likely involves speed bubbles and the Spiritual Realm in some way (which is already involved with speed bubbles as there is a transfer of energy in and out of the Spiritual Realm to prevent irradiating people, this loss of energy is the key to cracking the Allomantic FTL). It is confirmed that they will travel FTL in the Physical Realm. The Spiritual Realm breaks causality so investiture is already breaking the rules. We should probably expect something similar to the Alcubierre Drive, which works by bending spacetime itself around the spacecraft and so it happened that Allomantic time bubbles also work by pulling and pushing on spacetime around the Allomancer - that's probably how we'll get FTL. WoBs:

Spoiler

Questioner

You talked about Mistborn being the space traveler ones. I was wondering if you were going to utilize some of the speed bending into that, into the travel with it?

Brandon Sanderson

You will see what I do when I do that... The biggest problem is, for you physics majors, how we make sure that we're not breaking causality... So breaking causality is kinda my big no-no. For instance, I have right now that moving between Oathgates goes at the speed of light. But technically we still break causality, right, with Shadesmar stuff... But the issue--the way we can do it in Shadesmar is because it breaks causality, but there is so muc-- Like if you were able to go into Shadesmar, move at the speed of light, come out like, you could break causality but it's, in practice, impossible, because the difference is so slight.

We also break causality with the Spiritual Realm, but I can control that.

Questioner

Also you can just kind of like, mulligan that off.

Brandon Sanderson

...If we were having instant speed, communication and things like that... yeah if we have an ansible, that's how we're not breaking causality. How we're not doing the train thought experiment which breaks my brain...

So that's the big thing I have to worry about once we get to the Mistborn era, the space travel and stuff. Like, right now I don't break causality, or at least if I do, it is indiscernible to human ability to realize it. Once we get to actual space travel, and actual FTL, then I want to have rules in place, even if it is just like the rule for red shifts. On speed bubbles, where I say, "Yeah it just doesn't happen." Letting you know. But it would be no fun. Even if it's just that. But I at least want to have that in hand.

Emerald City Comic Con 2018 (March 1, 2018)

 

Spoiler

Questioner (paraphrased)

Can Investiture be used to go faster than the speed of light?

Brandon Sanderson (paraphrased)

Yes, in many different ways, some much easier than others.

Arcanum Unbounded Fort Collins signing (Nov. 29, 2016)

 

Spoiler

discipleofhoid (paraphrased)

At the signing I asked Brandon to personalize the book with a suggestion for a unique or rare effect that could be achieved with a metal. He signed

"Watch for what happens when something leaves a bendalloy bubble."

He then laughed and said "That won't make any sense for 10 books"

This leads me to believe that this might be related to the FTL travel.

Miscellaneous 2011 (Nov. 10, 2011)

 

Spoiler

ericpeters

You mentioned friday night in Seattle Allomacy has “FTL” built into it, any more hints you can share on how that would work

Brandon Sanderson

It involves where the lost energy from thermodynamic issues goes in certain Allomantic interactions

General Twitter 2011 (Nov. 14, 2011)

 

Spoiler

Questioner

So my quick question: Can you use Identity (I love the speed bubbles!) to anchor speed bubbles to yourself?

Brandon Sanderson

Uh, this is possible. That's less a matter of Identity. What’s gonna happen there, like, the more someone uses the powers, the more familiar and intermingled with their soul the powers become, and they are able to accomplish things that others can't. This would be like a Mistborn learning to hover a coin, right, which they can do, but most think you can't. That's the sort of level we're going with.

Necarion

So a savant could?

Brandon Sanderson

A savant could totally do that. The problem is, things moving in and out of a speed bubble, there's a transference of energy. This is how we keep speed bubbles from irradiating people when light moves through them, right, red shift. And so there's a transfer of energy directly from the Spiritual Realm, which means that moving with a speed bubble, you're gonna run into that, and it's gonna be, it's gonna cause all kinds of problems, but it would be possible.

Arcanum Unbounded San Francisco signing (Nov. 30, 2016)

 

Spoiler

Questioner

So as I was researching all the stuff for trivia, I must say I was-- I became intrigued with the idea of duralumin and bendalloy or cadmium and whether or not it might have something to do with your FTL?

Brandon Sanderson

It's a good theory. That's a really good theory.

Questioner

Would you like to expand on that?

Brandon Sanderson

No, that's it. That's a good theory.

Shadows of Self release party (Oct. 5, 2015)

 

Spoiler

Kurkistan

If I get a Slider, a Pulser, and a Nicroburst in a rocket with a lot of metal, do I have FTL?

Brandon Sanderson

Hehehehe. You're getting closer but you haven't figured it out yet.

Words of Radiance Philadelphia signing (March 21, 2014)

 

Spoiler

Kurkistan

If I get a Slider, a Pulser, and a Nicroburst in a rocket with a lot of metal, do I have FTL?

Brandon Sanderson

Hehehehe. You're getting closer but you haven't figured it out yet.

Words of Radiance Philadelphia signing (March 21, 2014)

 

Spoiler

Steeldancer (paraphrased)

Have you ever heard of the Alcubierre Drive? 

Brandon Sanderson (paraphrased)

Yes, I know about the Alcubierre drive. 

Steeldancer (paraphrased)

So, if we took two speed bubbles--mechanized, because Allomancers aren't powerful enough to pull it off--could we create a functioning Alcubierre drive?

Brandon Sanderson (paraphrased)

You are theorizing in the right direction. 

FanX Spring 2019 (April 19, 2019)

 

[Heilven he/him]

On 2/4/2025 at 1:25 PM, Hovestol said:

All things that have energy also produce a gravitational field proportional to the amount of energy. 

This is not true. Mass causes gravitational fields, not energy.

Investiture is massive, but we have no reason to believe that anti-investiture behaves any differently than anti-matter

[Hovestol]

Mass is really just tightly bound energy, they're the same thing. We don't typically see massless things have a gravitational effect for the same reason you don't notice the things around you gravitationally attracted to you. The earth is so much bigger than you, and mass is extremely energy dense (e=mc^2 is the conversion rate between rest mass and energy. c^2 is a huge scaler. It's actually a shortened infinite series that adds up a bunch of velocity terms, so we call that rest mass cause at rest the velocity terms are all 0) and so massless things have much less of an effect. Also massless things have to always move at the speed of light, so they're not around long to actually have an effect. 

There's actually a fun thought experiment about this, highlighted in this link: https://physicsdetective.com/the-mystery-of-mass-is-a-myth/
I haven't read the whole article (I was just wanting this one example) but the section labeled "The photon in the mirror-box"  has a description of it. Effectively the idea of mass and energy are the same, like particle and wave. 

[+Oltux72 he/him]

On 2/8/2025 at 12:19 PM, LockDown Ammo said:

There were also some theories on Seons communicating via FTL but considering the delays in conversation between Shallan and Kelsier could mean that is not the case.

Gavilar and Thaidakar having a real time conversation across how many light years are between Roshar and Scadrial mean that Seons are FTL.

I'd say the gaps in the communication between Shallan and Thaidakar are because Thaidakar would simply hear nothing if his Seon played sound at real time. Her speech would be incomprehensible low in pitch. So he listens and replys to her messages at his convinience.

[LeondeBowa]

On 3/19/2025 at 9:36 AM, Oltux72 said:

Gavilar and Thaidakar having a real time conversation across how many light years are between Roshar and Scadrial mean that Seons are FTL.

I'd say the gaps in the communication between Shallan and Thaidakar are because Thaidakar would simply hear nothing if his Seon played sound at real time. Her speech would be incomprehensible low in pitch. So he listens and replys to her messages at his convinience.

I thought the Seon worked through access to the spiritual realm?

As the spiritual realm has no time or space it would basically act like a wormhole between two points right? Effectively making the distance zero

[Nitpicking]

3 hours ago, LeondeBowa said:

I thought the Seon worked through access to the spiritual realm?

As the spiritual realm has no time or space it would basically act like a wormhole between two points right? Effectively making the distance zero

Right, but the Rosharan system is in a time bubble. Time there is moving far slower than the rest of the Cosmere (aside from other time-slowed places, like near a black hole).

[LeondeBowa]

12 hours ago, Nitpicking said:

Right, but the Rosharan system is in a time bubble. Time there is moving far slower than the rest of the Cosmere (aside from other time-slowed places, like near a black hole).

But that wouldn't be affected with the spiritual realm as it is effectively "outside" of time.

The Seon would still have to slow or speed up the "recording" but they are not transferring information at ftl speeds, they are just using a shortcut

[Nitpicking]

10 hours ago, LeondeBowa said:

The Seon would still have to slow or speed up the "recording" but they are not transferring information at ftl speeds, they are just using a shortcut

If the information arrives at a rate measurable as "more than one light second per second" it's faster than light. That's what "faster than light" means.

(Physics teacher son of a philosopher/lawyer here. Definitions matter to me.)

[LeondeBowa]

And at which point is it arrived at that speed? At each point in the relevent plane it is acting  at the speed of thought which is definitionally less than the speed of light in a vacuum, just because one plane is acting in a speed greater than the other does not mean they are acting faster than the speed of light

[Nitpicking]

Like all ansibles, seon communication is not compatible with relativity. If you can transmit information faster than c, relativity is wrong (or you lose causality). Brandon's spitballing, he knows perfectly well his world isn't ever going to really follow our world's natural laws.

[LeondeBowa]

Nitpicking, that's like saying the existence of a phone in story is not compatible with relativity. 

There are ways by defining the communication that it can still work under relativity.

I'd agree it is possible it is breaking relativity but we don't actually know. My point is there are ways we see everything that is happening now without ftl and relativity remaining intact.

[LeondeBowa]

So just to explain my idea of how the communication could work.

Basically the comprehension of the message on receipt is limited by the receivers ability to process information (P) and as this is the seon on both sides we can assume this is equal, we can also make the assumption that the transmission speed is limited by the same value (P). For any transition to work the transmission speed (Pt) has to be less than the receiver speed (Pr) with the best result being they are as close to equal as possible. If they are moving over planes which are moving at different rates the transmission is sped up or slowed down by that factor (v).

So Pt<=Pr

And when moving to the other plane

Pt'=Pt*v

This can lead to the case where Pt' is too large and is greater than Pr, and as such Pt' needs to be reduced. The easiest way to do this is for the transmitter Pt to be reduced by v before transmission.

So Pt' =Pta*v=(Pt/v)*v

This all works under relativity without requiring ftl.

[+Oltux72 he/him]

3 hours ago, LeondeBowa said:

So just to explain my idea of how the communication could work.

Basically the comprehension of the message on receipt is limited by the receivers ability to process information (P) and as this is the seon on both sides we can assume this is equal, we can also make the assumption that the transmission speed is limited by the same value (P). For any transition to work the transmission speed (Pt) has to be less than the receiver speed (Pr) with the best result being they are as close to equal as possible. If they are moving over planes which are moving at different rates the transmission is sped up or slowed down by that factor (v).

So Pt<=Pr

And when moving to the other plane

Pt'=Pt*v

This can lead to the case where Pt' is too large and is greater than Pr, and as such Pt' needs to be reduced. The easiest way to do this is for the transmitter Pt to be reduced by v before transmission.

So Pt' =Pta*v=(Pt/v)*v

This all works under relativity without requiring ftl.

Suppose you have a sender A and a responder B, as well as a listener C.

B is closer to C than A is to C. If A sends a message to B via FTL, then C will see B reply before C will see A sending the message. The issue with FTL is not between is not in transmission speed. It is in the sequence of events. If you have FTL, you will have frames of reference in which causality is violated.

[LeondeBowa]

But by using the spiritual realm as a wormhole by the Seon, as it is a closed system it isn't possible for a listener c to exist

And even if it is the soonest that a listener c would hear the information is the same as responder b

As the distance between A, B and C is considered zero