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[Bands Spoilers] Redshift - because someone has to!


aeromancer

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Now, a redshift is a way of measuring a direction of a traveling star. This is because light comes in tasty flavors called spectrum, like the seven colors of the rainbow. Now, the reason red is on the inside is because it has the shortest spectrum (or actually red has the shortest spectrum because it is on the inside.) Therefore, red has the lowest frequency, and thus the highest wavelength. A star moving away from you experiences a redshift, meaning the object appears more red. Slightly.

 

So, let's say a photon travels across a hall. Another one tries to on the same parallel track, leaving at the same time, but is in fact smashes through Wayne's bubble. (Pesky Wayne.) So, which one reaches the opposite side first?

 

It's a tie. Lightspeed is a constant. Hence, no redshift. Even Wayne cannot mess with that. However, theoretically seeing as the photon going through the bubble is "sped-up", the photon should experience a negative redshift, aka a blueshift.

 

Alright. I got this out into the open. Now someone with a Ph.D. in Physics make me eat a nice helping of humble pie.

Edited by Rubix
This thread belongs in the Bands board during the spoiler period.
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My main problem is that why would the person observing the effect have such a question. If she knows enough about physics to know about redshift, then she should also know that the speed of light is constant under all observations.

On second thought - I'd say you'd have to manipulate space to achieve a redshift, but time is space (sort of), so maybe a redshft should be achieved. I need clarification from someone who does these kinds of things for a living. Would creating a pocket dimension resulting in a photon being able to cross a distance faster than another photon cause said photon to have a different wavelength?

Edited by aeromancer
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From what I know, there should definitely be some red and blue shift occurring (know as the Doppler effect). There are a couple of factors here.

 

First, the time bubbles should be manipulating space and time since they are parts of the same substance. This is evident in the fact that when objects like bullets hit the bubble's edge they change trajectories. It also known that warping space-time causes a red shift to occur like when light passes through a gravity well. By what factor I can't say.

 

Second the rapid movement of the people inside the bubble should show this shift. If they are moving towards the observer they should appear slightly shifted towards the blue end, away and they should be shifted towards the red. It may be that the shifts are not large enough to be noticeable. You should however be able to tell if they are red shifted by using a radar speed gun, since those work off these same principles by using microwaves instead of visible light.

 

If anyone is interested I may be able to compare the speeds on known red shifted galaxies and try to calculate the speeds of people as they are moving in the bubble.

Edited by Vitex
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Brandon did indeed originally plan to have redshift in the bubbles, and Peter told him he'd microwave everyone that way. So Brandon had to figure out how to fix that in Realmatics. So, like with storing weight, there's something wonky going on in order to make it work.

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Link:

Kurkistan: Is there- have you come up with a Realmatic explanation for why light isn't affected by time bubbles besides handwavium "please don't burn people with microwaves"?
Brandon: Peter's got one for us. 'Cause we were going to do redshift: like the actual original writing for it had redshifts; Peter's like "dude, you will microwave everybody"—I'm like "oh man". So the handwavium of that: there is a real- there is an actual explanation, but it-
<at this point we decamp to the sidewalk outside the store>
Brandon: What's the middle of this question?
Kurkistan: Middle of the question was you were thinking about explaining the realmatics behind light for time bubbles.
Brandon: Oh right, right right right right. I can't because it spoils future books; like that's spoiler for Mistborn... 10?
Kurkistan/Argent: <Laughter>
Brandon: So... if you count the four Alloys, so really gotta stay away from stuff like that.
Kurkistan/Argent: That's fair/fine.

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The simplest explanation I can think of for the lack of red shifts is that, in the Cosmere, the speed of light is not constant for all observers, which would also open up the possibility of faster-than-light travel.  I only have my Bachelor's in Physics, so don't take my word as law on the subject, but for the most part I don't think this rule-change from how our universe works would cause all that many issues (considering the theory of relativity is only about 100 years old) and would be a simple and elegant explanation.

 

My best guess as to why Brandon Sanderson has declined to commit to an explanation so far is because they probably haven't decided exactly what technologies they want to showcase in the last Mistborn trilogy, as some modern techs would be deeply affected by a lack of Relativity, whereas others would function more or less unchanged from how we know them.

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I was under the impression that you only saw that red shift when you were going near the speed of light.

 

Given that everything we see, when looking into the night sky is only slightly red.  And those items are traveling as fast as possible (IE, speed of light).  Though take my post with a grain of salt, as my understanding of these things comes from the discovery channels short series "Into The Universe by Steven Hawking".

 

Edit: corrected the series name

Edited by mattig89ch
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Redshift/blueshift has nothing to do with the speed of light. (Light being redshifted over large distances does not mean it's moving more slowly, as the speed of light is constant.) In the case of galaxies moving away from us having redshift, it's to do with the Doppler effect. But this has nothing to do with time bubbles - inside a time bubble, you're not moving away from light faster.

 

When we talk about redshift/blueshift in the context of time bubbles, we're talking about a change in the light's frequency.

 

As time bubbles show off, everything inside is "sped up" a great deal, so a photons' frequency should also be increased by a hundredfold or whatever. A photon's "color" is based on its frequency. You should get redshift/blueshift in a time bubble, or so we'd naively expect.

 

But we don't, so the physics behind time bubbles is obviously not just a naive "speed things up" applied to everything in them.

 

Again, we see this with light: inside a speed bubble, everything outside should seem dark, because you're getting 1/100th (or whatever) of the photons in your eye per cycle of your brain. But you don't. So clearly time bubbles are producing tons of extra photons to compensate, or else something else really weird is going on.

Edited by Moogle
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Redshift/blueshift has nothing to do with the speed of light. It's to do with the photons' frequency. And, as time bubbles show off, everything inside is "sped up" a great deal, so a photons' frequency should also be increased by a hundredfold or whatever. You should get redshift/blueshift in a time bubble, or so we'd naively expect.

 

But we don't, so the physics behind time bubbles is obviously not just a naive "speed things up" applied to everything in them.

 

Again, we see this with light again: inside a speed bubble, everything outside should seem dark, because you're getting 1/100th (or whatever) of the photons in your eye per cycle of your brain. But you don't. So clearly time bubbles are producing tons of extra photons to compensate, or else something else really weird is going on.

 

Agreed, something wonky must be taking place.  I'm confident someone will find a way to reconcile the weirdness someday, but maybe the ultimate lesson to take away from all of this is that relativistic and astrophysics are hard.

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See now, in that series the reasoning explained for the red/blue shift is something moving toward or away from us.  Anything moving toward us is slightly blue, and anything moving away from us is slightly red.  This is in the scene with the car on the road btw, in case you wanted to look it up.

 

And since everything in the sky is moving away from us near the speed of light, we see everything as slightly red.  Not very red, only slightly red.  One would assume that the speed at which something is moving toward or away from you is the key to a red/blue shift in color.

 

Unless the discovery channel, in cooperation with Mr. Hawking, got it wrong of course.  Lets face it, TV channels aren't exactly known for their fact checking.  I'd get you a video link, but I'm at work at the moment

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Ok, just throwing this out there: since we are dealing with space-time and from the WoB it seems that Sanderson is using Realmatic Theory to get FTL travel, let's assume that the speed of light is constant. In that case, what we're left to play with is time-space - what if, instead of affecting time, the bubbles are actually affecting space?

Initially,  let's say that when an object/matter/energy enters the bubble, it enters a place that is either significantly larger or significantly smaller than the space outside the bubble - then, the objects will be travelling at the speed they entered the bubble, but because they're covering way more ground/significantly less ground, it takes either much longer, or much less time for them to cover ostensibly the "same" distance than outside the bubble (e.g. inside the bubble, effectively, 1 m = 10 m outside, an object moves in at 1 m/s, outside the bubble it will take 10 s to move across that distance, whilst inside the bubble it will only take 1s as it effectively moves across 1m, thus making the object move "faster", since from the point of view of the external observer the object just moved 10m inside the bubble in 1s). Where does this extra space come from, or where does extra space go? Who knows! But it does avoid the issue of both red-shifts and all those nasty problems with sounds!

So, I kind of made that up as I read the thread, so this is very rough thinking - please feel free to correct/rubbish the idea, good Physics and non Physics folks!

 

This does not really address the weird "brownian motion affected refraction" at the boundary where the objects are slightly deviated here and there, but maybe it could be explained by air molecules popping in and out of the bubble and thus drastically changing their momenta, which will affect the pressure a little bit at the bubble boundary making it "wobble" and "wrinkle" and "wilt" at any given time, thus affecting object/bullet trajectories.

 

 

PS
Space is then either stretched or compressed to fit the boundary of the bubble depending on whether it is supposed to speed up or slow down time. Also, "internal space reference frame" and "external space reference frame" pops up in my mind.

Edited by KOOZ
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Wrinkle in time, much? Yeah, that sounds plausible. Technically light should exceed light because it's traveling in  separate "pocket dimension" these bubbles create. These bubbles are definitely pocket dimensions if they mess with time - which I'm still not convinced that they do.

 

What else than? Gravity, perhaps.

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Just and idea, but I'm thinking that the time bubbles cause some interesting things with the cognitive space. I think I remember Brandon saying something on the lines of an object either knows it's inside or outside the bubble and can't be both. This sounds like cognitive concept, like the object has to make the determination. If this is the case then the whole perception of time must carried by the people and objects inside the bubble. Photons are just particles and have no cognitive ability therefore ignore the bubble entirely and carry on business as usual.

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Ok, just throwing this out there: since we are dealing with space-time and from the WoB it seems that Sanderson is using Realmatic Theory to get FTL travel, let's assume that the speed of light is constant. In that case, what we're left to play with is time-space - what if, instead of affecting time, the bubbles are actually affecting space?

Initially,  let's say that when an object/matter/energy enters the bubble, it enters a place that is either significantly larger or significantly smaller than the space outside the bubble - then, the objects will be travelling at the speed they entered the bubble, but because they're covering way more ground/significantly less ground, it takes either much longer, or much less time for them to cover ostensibly the "same" distance than outside the bubble (e.g. inside the bubble, effectively, 1 m = 10 m outside, an object moves in at 1 m/s, outside the bubble it will take 10 s to move across that distance, whilst inside the bubble it will only take 1s as it effectively moves across 1m, thus making the object move "faster", since from the point of view of the external observer the object just moved 10m inside the bubble in 1s). Where does this extra space come from, or where does extra space go? Who knows! But it does avoid the issue of both red-shifts and all those nasty problems with sounds!

So, I kind of made that up as I read the thread, so this is very rough thinking - please feel free to correct/rubbish the idea, good Physics and non Physics folks!

 

This does not really address the weird "brownian motion affected refraction" at the boundary where the objects are slightly deviated here and there, but maybe it could be explained by air molecules popping in and out of the bubble and thus drastically changing their momenta, which will affect the pressure a little bit at the bubble boundary making it "wobble" and "wrinkle" and "wilt" at any given time, thus affecting object/bullet trajectories.

 

 

PS

Space is then either stretched or compressed to fit the boundary of the bubble depending on whether it is supposed to speed up or slow down time. Also, "internal space reference frame" and "external space reference frame" pops up in my mind.

 

I like your thinking, but space and time are part of the same space-time "fabric." What you describe accomplishes the same thing, and is functionally the same as speeding up time. In fact it doesn't matter which perspective you choose both are actually correct. That is some of the crazy stuff Einstein's Relativity describes.

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I like your thinking, but space and time are part of the same space-time "fabric." What you describe accomplishes the same thing, and is functionally the same as speeding up time. In fact it doesn't matter which perspective you choose both are actually correct. That is some of the crazy stuff Einstein's Relativity describes.

Cheers. That was exactly the point - I just thought that tackling it from the "space" perspective is  easier to see how things can unfold so we can hand-wave the redshifts away. 

 

 

PS

Looked at my original post wording - should have worded it way better when introducing bubbles affecting time "or" space - I meant looking at perspectives there.

Edited by KOOZ
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Hasn't, in a way, the question of redshift been answered in the Alloy of Law annotations?

 

In them Brandon says that bubbles absorb the excess kinetic energy of objects leaving them.  This could probably be extrapolated to apply to light as well, as a change in wavelength is roughly equivalent to a change in energy.

 

For Cadmium bubbles I presume the effect would be reversed, with the bubble injecting extra energy to get things to where they should be

Edited by Master_Moridin
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Hasn't, in a way, the question of redshift been answered in the Alloy of Law annotations?

 

In them Brandon says that bubbles absorb the excess kinetic energy of objects leaving them.  This could probably be extrapolated to apply to light as well, as a change in wavelength is roughly equivalent to a change in energy.

 

For Chromium bubbles I presume the effect would be reversed, with the bubble injecting extra energy to get things to where they should be

 

Cadmium bubbles - Chromium leeches metals.  And possibly, although Khriss probably hasn't made that particular connection yet.  

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  • 2 weeks later...

Light, apart from a photon, is a wave. Brandon has mentioned somewhere that if something is half in, half out of a speed bubble, wether it is sped up depends on how said object sees itself. The way I see it is this. When the light sees itself as inside the speed bubble, the whole beam is suddenly incorporated at the same time. Now, as mentioned in the main post, the speed of light is constant. either the light sees itself as completely out of the bubble, or it progresses inside the bubble, entering the bubble instantaneously, without crossing any sort of 'boundary'. This would mean no red shift.

 

That's how I always saw it, at least.

Edited by timasp
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