Using the sun for directions?

[Jofwu]

Kenton seems to suggest that he uses the position of the sun in the sky to tell directions (chapter 3). But the sun is also supposed to be "fixed" in place in the sky.

Anyone know how to make sense of that?

[Blightsong]

Think of it like this, the sun doesn't move in the sky but when someone moves the sun will change position in the sky. If you tape a sheet of paper to your ceiling it won't move, but if you do you have to look in a different direction to see it. Daylanders can use this to tell where they are in relation to other places.

[Oversleep]

Anybody a scientist here? Because for me it's pure nonsense. The sun is too far to any change be noticeable.

[Jofwu]

13 hours ago, Blightsong said:

Think of it like this, the sun doesn't move in the sky but when someone moves the sun will change position in the sky. If you tape a sheet of paper to your ceiling it won't move, but if you do you have to look in a different direction to see it. Daylanders can use this to tell where they are in relation to other places.

No, @Oversleep is right.

Earth's diameter is 12,756km and the distance to the Sun is 149,600,000km. This means if you travel from one side of the Earth to the other (in an instant) the Sun will have moved 0.005 degrees (18 arc seconds) in the sky. That's roughly the diameter of Saturn, as it appears to us in the night sky. In other words, the sun would have moved the width of a bright point of light in the sky. Almost nothing. And that's if you travel clear across the planet. Let's say you ride a tonk all day, traveling an impressive 200km. I'm getting 0.3 arc seconds, which is smaller than Ceres. Something you can't see without magnification.

You might argue that the Taldain system isn't comparable to our situation on Earth, but I think it's actually "worse". AU essay spoilers:

Spoiler

Taldain's star is a supergiant, yet there's no indication that it's significantly bigger in the sky than our own sun. In any case, we can definitely assume that Taldain is further from it's star than Earth is to the Sun. This means the numbers above are conservative.

Taldain's sun definitely doesn't move depending on your perspective.

My best guess is that Taldain isn't 100% tidally locked to the sun. In other words, it's got some slight wobble as it orbits. This would mean that the sun shifts back and forth (or maybe in a circle) every so slightly. I don't know enough astronomy to say if this is realistic or how perceptible it would be on the surface. The main problem with this theory is that it seems to be shot down by assertions that the sun is "motionless" in the sky.

My next best guess is that Kenton is making crap up so impress them or to sound indispensable or something. Or maybe he really does believe he can tell the difference, but it's really just his subconscious making use of other natural methods of navigation.

[Blightsong]

4 minutes ago, jofwu said:

No, @Oversleep is right.

Earth's diameter is 12,756km and the distance to the Sun is 149,600,000km. This means if you travel from one side of the Earth to the other (in an instant) the Sun will have moved 0.005 degrees (18 arc seconds) in the sky. That's roughly the diameter of Saturn, as it appears to us in the night sky. In other words, the sun would have moved the width of a bright point of light in the sky. Almost nothing. And that's if you travel clear across the planet. Let's say you ride a tonk all day, traveling an impressive 200km. I'm getting 0.3 arc seconds, which is smaller than Ceres. Something you can't see without magnification.

You might argue that the Taldain system isn't comparable to our situation on Earth, but I think it's actually "worse". AU essay spoilers:

  Hide contents

Taldain's star is a supergiant, yet there's no indication that it's significantly bigger in the sky than our own sun. In any case, we can definitely assume that Taldain is further from it's star than Earth is to the Sun. This means the numbers above are conservative.

Taldain's sun definitely doesn't move depending on your perspective.

My best guess is that Taldain isn't 100% tidally locked to the sun. In other words, it's got some slight wobble as it orbits. This would mean that the sun shifts back and forth (or maybe in a circle) every so slightly. I don't know enough astronomy to say if this is realistic or how perceptible it would be on the surface. The main problem with this theory is that it seems to be shot down by assertions that the sun is "motionless" in the sky.

My next best guess is that Kenton is making crap up so impress them or to sound indispensable or something. Or maybe he really does believe he can tell the difference, but it's really just his subconscious making use of other natural methods of navigation.

What I described is what Kenton describes in the prose version as well.

[Jofwu]

Just now, Blightsong said:

What I described is what Kenton describes in the prose version as well.

What page?

I feel like this is the sort of scientific thing Brandon pays attention to getting right. But I guess maybe that wasn't the case back when he wrote the prose, and I can see how it would get looked over when adapting for the graphic novel.

[Blightsong]

4 minutes ago, jofwu said:

What page?

I feel like this is the sort of scientific thing Brandon pays attention to getting right. But I guess maybe that wasn't the case back when he wrote the prose, and I can see how it would get looked over when adapting for the graphic novel.

I'm not sure, and the PDF that I used to read it doesn't have a find in page function.

 

Look at the star chart for Taldain. The sun seems much closer to Taldain than is normal or reasonable. The star charts obviously aren't to scale, but my theory is that the sun is legitimately extremely close to Dayside, and that autonomy has altered the goldilock zone in some way to allow Taldain to be inhabitable.

[Jofwu]

1 minute ago, Blightsong said:

I'm not sure, and the PDF that I used to read it doesn't have a find in page function.

 

Look at the star chart for Taldain. The sun seems much closer to Taldain than is normal or reasonable. The star charts obviously aren't to scale, but my theory is that the sun is legitimately extremely close to Dayside, and that autonomy has altered the goldilock zone in some way to allow Taldain to be inhabitable.

Ah well, I'll try and find it myself.

As for the scale, I'm not sure you understand. If Taldain had the same orbital height as Earth then it would pretty much be inside its star. I believe that this image is on the large end for supergiant stars, but even if Taldain's is ten times smaller they'd be screwed. It's one thing to shift the habitable zone... This would be something else.

[Rasarr]

I'm inclined to agree that this is an artifact from the prose version, which was, after all, written back when Brandon's physics weren't as solid and well-checked as they are now. If we're looking for an in-universe explanation, I like @jofwu's idea that Kenton's just making stuff up as he goes for the Darksiders. 

[Blightsong]

1 minute ago, Rasarr said:

I'm inclined to agree that this is an artifact from the prose version, which was, after all, written back when Brandon's physics weren't as solid and well-checked as they are now. If we're looking for an in-universe explanation, I like @jofwu's idea that Kenton's just making stuff up as he goes for the Darksiders. 

I dont think Brandon would include something that breaks physics for nostalgia's sake unless he could come up with a Realmatic explaination.

 

1 hour ago, jofwu said:

Ah well, I'll try and find it myself.

As for the scale, I'm not sure you understand. If Taldain had the same orbital height as Earth then it would pretty much be inside its star. I believe that this image is on the large end for supergiant stars, but even if Taldain's is ten times smaller they'd be screwed. It's one thing to shift the habitable zone... This would be something else.

I'm not saying it has the same orbital height of earth, im saying it may be much closer, by scale, than earth is to the sun (but obviously not inside of it). I dont doubt that a Shard is powerful enough to maintain a habitable climate on a planet in this circumstance, and its the only theory i can come up with to explain this without studying. Although my planetary physics is weak, I wouldnt be surprised if I am embarrassingly off the mark here as far as plausibility goes.

[Jofwu]

4 minutes ago, Blightsong said:

I'm not saying it has the same orbital height of earth, im saying it may be much closer, by scale, than earth is to the sun (but obviously not inside of it).

Ah, I see what you're saying. Scale isn't part of the equation. All that matters for the calculation is how far you are from the center of the object (the sun) and how far you move perpendicularly to it (along the surface of the planet).

I don't mean to say that Brandon knowingly left the 'error' for the heck of it. I think it's more likely that he (and Peter and whoever else) were less observant to this kind of detail than they normally are, for one reason or another. Given the number of other small mistakes, that doesn't strike me as particularly surprising.

[1stBondsmith]

My Friends, @jofwus calculations are correct, but they miss the point. Kenton is not noticing the displacement of the sun based on a static point reference, he is noticing the difference from the angle he is standing relative to the sun. I will give you a concrete example, based on the Earth. 

When I was in Brazil, the sun was directly overhead. When I was in Mexico the next week, it was noticeably south, about 15 degrees. In Utah, about 10 more degrees. Then flown to Barrow, Alaska, it was at 80-85 degrees south. The sun position had not changed, my vertical position changed, so the observed angle changed. If Taldain is smaller than Earth (and I believe it is), this angle change would be even more noticeable. This subtle change would be highlighted if the sun never moved with seasons. I have been accurate in time within 5-6 minutes by solar position when I have lived in the same place for several years. Someone in the same place their whole life, with a fixed sun and a smaller planet could quite possibly tell position by a day's travel. 

Submitted for your contemplation.

Edited January 13, 2017 by 1stBondsmith
Fixing spellcheck

[Jofwu]

@1stBondsmith Ah, of course! It's about the curve of the planet itself. Not a matter of how you move relative to the sun, but of how the Sun moves relative to the ground and your sense of "up". If you're at a pole the sun is on the horizon and if you're in the middle of Dayside then it's directly above. Every degree of latitude or longitude is one degree of sun movement.

Let's say you can make out a 3 arc minute shift of something in the sky (1/10th of the diameter o the Sun or Moon). That's 1/20th of a degree. Moving 1/20th of a degree along Earth's surface is 3.5 miles. I don't think Taldain is significantly smaller than Earth. (Does AU say?) But even if it's not, it seems totally reasonable to me that someone might be able to detect that kind of movement .

Surely this is the answer. Thanks for helping me make the connection!

@Blightsong, sorry if that's what you were trying to get across and I was just thinking too hard to see the difference.

Edited January 13, 2017 by jofwu

[Lirin's hand]

Another way to think of it: the sun is the #1 constant; other physical points on the planet (mountains, river, ocean, etc) are the second constant; you are the variable, the third point, for triangulation purposes.

If your whole life is centered on those two constants, I would think the triangulation for direction would become second nature.  Khriss, being from darkside, would not have that habitual triangulation/direction sense on dayside.