Astronomy in Mistborn

[TheWisestBear]

Hi all,

If anyone is interested in the astronomy in Mistborn, I discuss the plausibility and implausibility of the ending of the Hero of Ages here:

https://youtu.be/84ZWDwBt4P4

Let me know what you think!

 

[alder24]

10 hours ago, TheWisestBear said:

Hi all,

If anyone is interested in the astronomy in Mistborn, I discuss the plausibility and implausibility of the ending of the Hero of Ages here:

https://youtu.be/84ZWDwBt4P4

Let me know what you think!

Welcome to the Shard. You're a very wise bear, great observations. But...

Constellations and zodiac signs. While the orbit of Scadrial was changed, the calendar used by Scadrian wasn't. TLR still forced usage of old callender, which didn't line up with new seasons and with the position of constellations in the sky. This is the easiest way to explain how Sazed was able to use ancient sky maps. 

Spoiler

king of nowhere (paraphrased)

The lord ruler moved Scadrial closer to the sun, and orbital dynamics dictate that so its time of revolution would also become shorter. how did that impact the ages of the characters, and how did it impact the 1024 years of refilling of the well?

Brandon Sanderson (paraphrased)

He said that Arcanum unbounded will contain all the calendars and that peter made actual orbital calculations. Brandon also confirmed that the characters ages were really earth ages, and that the lord ruler kept the old calendar in the final empire, even though it did not fit with the length of the year. That sounded very strange to me, but then I remembered that we already have the Islamic calendar who doesn't follow the year, so a calendar not coinciding with the year is something never seen before. he also confirmed that modern Scadrial has an earth-like year duration, which we already knew. he said that people only started asking that in the last year and he was surprised it took that long to ask about that.

Lucca Comics and Games Festival (Oct. 28, 2016)

 

If Nelazans were able to produce super-precise star maps, Sazed as a Shard, with sight unmatched by human eye, would be able to pinpoint location of pre-Rashek Scadrial. Before Rashek's Ascension, Scadrial was technologically advanced, with gunpowder and trains present, which ensured the existence of sophisticated telescopes. What do you think?

Also, nitpicking (because I love to do that), you said that Earth would have to move several light years to see changes in the position of stars in the night sky. I disagree. Alpha Centauri is just a few light years away, just 4.5 LY from Earth. This system is also the 3rd brightest in the night sky. Moving Earth by several light years closer to or further away from the Alpha Centauri would significantly change its brightness and position on the sky (when Earth is moved in a different direction). Of course this doesn't really matter on the scale we're talking about, less than 1 AU changes. But as I said, I'm nitpicking.

But now I also wonder how would your conclusion change if you take into account that Cosmere is a small star cluster, and distances between known worlds might differ from what we have in our stellar neighborhood. If it was a particularly compact region, with stars close to each other, would this create a more visible change when changing the orbit of Scadrial?

Spoiler

Windrunner

Threnody and Scadrial are both noted as having unusally bright patches of stars in their skies. Are these two planets near to one another?

Brandon Sanderson

They are both seeing the same thing, yes.

Windrunner

Does this mean that Threnody and Scadrial are part of the same system, or are these bright patches visible from other worlds as well?

Brandon Sanderson

Visible from other worlds as well. The cosmere is a relatively small place (on a galactic scale, that is.) We'll publish the star map when that becomes relevant in a decade or so.

Footnote: It took approximately a year and a half to publish the star map.
/r/books AMA 2015 (March 13, 2015)

 

Spoiler

Peter Ahlstrom

The involved [cosmere] planets are actually in a rather small star cluster, much smaller than a dwarf galaxy. This star cluster is within a galaxy.

Miscellaneous 2015 (July 1, 2015)

 

[TheWisestBear]

Thanks for that information about Scadrial's calendar being preserved and position in a star cluster.  We didn't know that.

Using the length of the original year + Kepler's 3rd law to place Scadrial's orbit would certainly be a lot easier than working out the positions of the planets.  However, the text of HoA explicitly says that Sazed used the star maps and planets to place Scadrial.  I guess that was the text that raised my human's eyebrows. 

Regardless of Sazed's Shard-like eyesight, he is limited by the precision of the Nelazan star maps, which would need to be as precise as the Gaia satellite (ie above the atmosphere kind of precision with tiny pixels) if he was going to use stellar parallax. 

Alpha Centauri is only the closest star.  The vast majority of the visible stars are 100's of light years away, including the brightest stars, so you'd still have to move the planet a long way in order to see the constellations change, and not just one or two stars.

Also even if Scadrial was in a star cluster, the typical distance between stars would be about a light year.  (If it's much denser than that, like in the core of a globular cluster, the  orbits of planets would not survive the gravitational interactions.) So if the Scadrial-sun distance was comparable to the Earth-Sun distance, that would produce a parallax angle of about 1/1000th of a degree, which is comparable to the degree of atmospheric blur on Earth.  Therefore the Nelazan maps would still look the same between the old and new orbits.

I'm also worried about the implications for the brightness of the stars in the cosmere.  A star like Betelgeuse for example, if it were 10 ly away, would be appear brighter than our Moon.  And every cluster has several red giant stars like Betelgeuse, or if it's a young cluster, it will have blue giants.  But I suppose stellar evolution might work differently in the cosmere.

Note that there are also implications for the orbits of the other planets if one planet is moved, because of the conservation of angular momentum.  But in my video I decided to ignore that effect (despite protests from my human buddy) because I figured people wouldn't be as interested in physics as they would be in astronomy .

As you can see, I love being nitpicky too!  

Just to be clear: I love Mistborn and all the cosmere books.  For me, picking fiction apart scientifically is fun, and in no way spoils my enjoyment of the stories.

 

[alder24]

9 hours ago, TheWisestBear said:

Using the length of the original year + Kepler's 3rd law to place Scadrial's orbit would certainly be a lot easier than working out the positions of the planets. 
However, the text of HoA explicitly says that Sazed used the star maps and planets to place Scadrial.  I guess that was the text that raised my human's eyebrows. 

Yes, it's often pointed out here that both Rashek and Sazed while holding powers of Shards should have known Kelper's 3rd law and be able to precisely correct Scadrial's orbit. While in the case of Rashek this might be excused as knowledge isn't equal to precision he had (even if he knew where, he wasn't skilled enough with power to put Scadrial on correct orbit and would always overshoot, and he couldn't practice to gain that skill as it would destroy Scadrial). 

Spoiler

Brandon Sanderson

Chapter Forty-Four - Part One

Subtlety with the Power

The Lord Ruler created koloss, kandra, and Inquisitors during his time holding the power. This took some practice and experimentation, however. As has been explained, holding the power granted some intuitive understanding of how to use it. For instance, he knew how to make Hemalurgic creatures—but he wasn't practiced enough with the specifics at first to know exactly what he wanted to make or what the results of his experimentations would be.

In a similar way, he knew that he could move a planet—and did. With practice, he could have figured out how to shove the planet the right way to place it correctly in orbit. Unfortunately, you can't really experiment with moving a planet around without causing a whole lot of damage.

And so, he could do something as subtle as create three new races—and, with that practice in biology, redesign the world's plants and animals slightly—but could be so far off in the way he shoved the planet about the first time.

The Hero of Ages Annotations (Dec. 4, 2009)

But Sazed should have known this. However my excuse is that knowledge is coming to a new Vessel gradually, and Sazed just tapped all memories from his metalminds. He had a clear image of star maps in his mind, while the Shadric knowledge of orbital mechanics wasn't there yet. Therefore he used star maps in the heat of the moment instead of waiting for knowledge to come to his (as people were burning on the planet and he had to act right now).

But those are my explanations for why they didn't use Kepler's 3rd law.

9 hours ago, TheWisestBear said:

I'm also worried about the implications for the brightness of the stars in the cosmere.  A star like Betelgeuse for example, if it were 10 ly away, would be appear brighter than our Moon.  And every cluster has several red giant stars like Betelgeuse, or if it's a young cluster, it will have blue giants.  But I suppose stellar evolution might work differently in the cosmere.

Oh yes, that's a problem. Bigger problem is a "blue white supergiant" star existing in the Taldain system, with a habitable planet in its orbit, tidally locked between that supergiant, and a white dwarf star on the other side of the planet. https://coppermind.net/wiki/Taldain_system

9 hours ago, TheWisestBear said:

Note that there are also implications for the orbits of the other planets if one planet is moved, because of the conservation of angular momentum.  But in my video I decided to ignore that effect (despite protests from my human buddy) because I figured people wouldn't be as interested in physics as they would be in astronomy .

Yes, but either within 1000 years this didn't cause any visible changes and later Sazed fixed this too, or Shardic power kept the system stable despite changes to Scadrial's orbit.

[Firesong]

My personal theory on the star thing, is that he wasn't relying completely on the Star Maps, but that there was a degree of Shardic memory in there. He might not have been completely consciously aware of it, but I feel that he would have some level of instinctual "this is correct".   He could also use the relative size of the sun, which I feel would also be felt in this instinctual connection to the past Vessels. 

It isn't absolute, and I am not gonna try and say this is exactly what happened, but it just makes sense to me that he would be influenced by that.  

[TheWisestBear]

18 hours ago, alder24 said:

Oh yes, that's a problem. Bigger problem is a "blue white supergiant" star existing in the Taldain system, with a habitable planet in its orbit, tidally locked between that supergiant, and a white dwarf star on the other side of the planet. https://coppermind.net/wiki/Taldain_system

A blue white supergiant?  Oh dear.  I do hope Autonomy is protecting that planet...

[TheWisestBear]

12 hours ago, Firesong said:

My personal theory on the star thing, is that he wasn't relying completely on the Star Maps, but that there was a degree of Shardic memory in there. He might not have been completely consciously aware of it, but I feel that he would have some level of instinctual "this is correct".   He could also use the relative size of the sun, which I feel would also be felt in this instinctual connection to the past Vessels. 

It isn't absolute, and I am not gonna try and say this is exactly what happened, but it just makes sense to me that he would be influenced by that.  

Hmm, interesting idea.  I think I do remember Sazed saying something like he remembers the history of the powers.