Science + Pop Culture, writing

Science Tangents: Avatar: The Last Airbender

I started rewatching the wonderful ATLA on Netflix – binging, of course – and made it to the penultimate episode of season 1 (aka Book 1) before I thought about any science no-nos.

That’s pretty impressive for a show that upholds the much-outdated idea that fire, water, air, and earth are elements.

elements
https://xkcd.com/965

Anyway, here are a few things that, during my binge, made my brain go, “No, that’s not right.” Even amidst a clearly fictional – or rather fantastic – story I very much hope Netflix does not pull a Shyamalan on whenever their adaptation comes out.


Book 1: Water

Come the end of this Book, we’re at the North Pole, or the version of the North Pole in the ATLA universe. Whose world looks like this:

cbfefbb6710e9e7817de1d66e0155a6f.jpg

I don’t know if it’s ever established that their world is flat/spheroidal – lots of fantasy doesn’t bother with that, unless you’re Tolkien, who explains that the world was flat, until partway through the Second Age a bunch of haughty humans decided to invade the lands of the little “g” gods to steal their immortality, and big “g” God killed them all as he ripped off the undying lands and made the rest of the world round. Fun times.

It’s not clear exactly when the season finale takes place, except that it has to be after the Winter Solstice,1 when Roku warns Aang about Sozin’s comet, which will return by the end of next summer. And Appa starts shedding for spring partway through Book 2. So it’s still winter up there.

In the real world, where the Earth is round, this is a time when everything above the arctic circle never sees the light of day. There’s still a bit of sunlight that eeks out from the horizon during some hours, but at best you get some kind of twilight.

If the ATLA world were round, I’d say it was way too bright during those episodes. But it’s probably not round, so my brain ignored that complaint.

Instead, what kicked me out of my suspension of disbelief was the Moon. Specifically, the following exchange about it:

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Yue: The legends say the moon was the first waterbender. Our ancestors saw how it pushed and pulled the tides, and learned how to do it themselves.

Katara: I’ve always noticed my waterbending is stronger at night.

[NB — most people don’t know that the Sun also causes Earth to have tides. Now you know and can impress people at parties.]

In the real world, the Moon and Sun aren’t opposite one another. One isn’t always rising when the other sets and vice versa.

For example, today where I live the Moon rose just after noon, and will set at about 4am tomorrow morning. Sunrise was at 7:01am and will set at 7:51pm. So there’s about 8 hours of overlap when they’re both above the horizon.

Moonrise shifts by roughly a half-hour every day, so in one week it will be more of a one in, one out arrangement. At the end of October, the Moon and Sun will rise at about the same time.

The reason for this is the Moon’s orbit around the Earth (which determines its position in the sky relative to the Sun) takes 28 days to complete. A full moon, which we see in these episodes, is as far away from the Sun in the sky as it can be, so it will rise at sunset.

8cbebdde052f6b012f1ba36d448254fc
Please ignore that 1. the Sun should be white, and 2. the obviously inaccurate placement and shape of Earth’s continents. Just enjoy the Oreos…

In other words, there’s nothing wrong with the events of this season finale. At least there wasn’t anything wrong until the very end. The Full Moon is out, now Sokka’s girlfriend, and it’s day.2

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That moment sealed this post’s fate, but it was Katara’s exclamation that set it in motion. If it’s supposed to be the presence of the Moon in the sky that amplifies her waterbending, it doesn’t only do so at night. During the other lunar phases, it’ll do so during the day, too.

It also doesn’t make sense that a Full Moon amplifies the power at all, because that just means the Earth is bathed in more (reflected) sunlight. And the Sun helps with firebending.

Boom. Scienced.

It’s almost as if we’re dealing with a world so nonsensical that putting a fish in a bag turns the Moon red.

Oh wait.

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Book 2: Earth

Sticking with the Moon, in episode 10 we learn solar eclipses happen in this world. And there’s one a few months away, which may provide a day in which to pound the Fire Nation army into dust.

This is thanks to an old school planetarium, which tracks the motion of the Sun and Moon. (No planets, though. Are there planets in this franchise?)

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At the moment of the eclipse, the two tracks line up forming a crosshair, and the Sun and Moon can move in opposite directions to meet up. It’s kind of hard to see in the screencaps, ’cause…ya know…they aren’t moving.

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This is wrong, at least in the real world, but it’s something I’m pretty sure you wouldn’t catch unless you had a degree in astronomy/astrophysics3, or were a serious amateur backyard astronomer.

It all comes down to the ecliptic. The plane that all the stuff (planets and moons and asteroids and whatnot) orbits the Sun in.

solarsys

Our world may not be flat, but the Solar System basically is; the Moon’s orbit is angled about 5 degrees from the ecliptic.

Also, the Moon orbits the Earth in the same direction that the Earth orbits the Sun.

These two facts together mean that the Sun and Moon always move across the sky in the same direction, tracing out roughly the same path. They both rise in the east and set in the west.

Scienced…in regards to an episode featuring a giant, talking owl spirit…

M.A. Seeds, The Solar System, 5th Ed., Thomson/Brooks-Cole, 2007.

Additionally, in the following episode (where Sokka drinks the cactus juice) Aang tries to collect water from a cloud and gets basically nothing. An average cloud weighs about a million pounds, most of that water. I only mention this because most people think clouds are wispy, weightless things because they float. But no. They’re massive.

There’s another thing you can fascinate people with at a party.

And extra bonus: here’s the animators correctly demonstrating the color of the Sun:

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Book 3: Fire

In episode 3, we learn that the solar eclipse will only last 8 minutes. Doesn’t seem very long — certainly not long enough to win an entire war against an entire nation. And yet, in our world, they’re often much shorter.

The exact length of time you experience totality (i.e. the moment when the Moon is so perfectly lines up with the Sun you get to see the corona) depends on 1. your exact location on the ground.

Here’s a map from the 2017 solar eclipse that crossed the continental US:

usa_eclipse_map_v2_print

That grey sliver is the path of totality. Inside this region, you actually got to see the full eclipse. But the closer to the center of that ribbon you were standing, the longer the eclipse would last.

ne_preview

I was in Nebraska for the event. Specifically Kearney, which if you look closely enough you’ll see is solidly on the 2 minute line. If we had been a little further north, we could have gotten the maximum 2:40. That’s the longest anyone in the States would have had, had they decided to battle some firebenders.

eclipse16
Photo credit: my dad

The length also depends on several other factors. Longer eclipses happen when:

  1. The Moon is as close to Earth as possible (i.e. “at perigree”)
  2. The Earth is as far away from the Sun as possible (i.e. “at aphelion”)
  3. The path of totality is closer to Earth’s equator, so the ground is rotating as fast as possible against how fast the Moon is orbiting us.
  4. The path of totality is closer to the part of the Earth where the Sun is directly overhead (i.e. “the subsolar point”)
  5. The path of totality is as horizontal (i.e. following lines of latitude) as possible.

According to one paper, the longest totality between the years 2000 B.C. and 7000 AD is 7 minutes, 29 seconds. in 1973 one lasted over 7 minutes, but the next that long won’t be until 2150.

The next total eclipse that crosses North America will have a maximum totality of about 4.5 minutes. This one in 2027 will be over 6 minutes, and the one in 2028 that crosses through my current city will be over 5.4


And how ’bout that space sword?

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Meteorites aren’t one-size-fits-all. They come in a range of compositions. The two main types are ‘stony’, meaning they’re primarily made of silicon-based minerals, and iron, meaning they’re primarily made of uranium (I’m hilarious — it’s iron and nickel). You can also have a blend, but something like 95% of the meteorites found on Earth are of the stony variety.

Iron meteorites are my favorite because the crystals have millions of years to grow into Widmanstätten patterns:

640px-Alvord_meteorite
Credit Jim H, CC BY-SA 2.0

A few swords have been made from meteoric iron over the years. Tentetsutou (i.e. “Sword of Heaven”) was made by Japanese swordsmith Yoshindo Yoshiwara; it’s on display at the Chiba Institute of Technology. (I don’t know the year he made it, but it’s been some time in the past half century…)

In 1814, Britain’s James Sowerby made a very curved blade (67 cm long) for Russian tsar Alexander I out of a meteorite that landed in modern-day South Africa. It was basically a thank you gift for his help defeating Napoleon. Took 10 hours to make, and 5 years to deliver.

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In the 1600s Mughal Emperor Jahangir had two swords and a dagger made partly from a meteorite. The pattern in the metal you can see in the dagger (“pattern welding”) comes from the fact that multiple metal sources were used.

msword01.jpg

King Tut was buried with a space knife, too. (You might wonder how we can tell these old blades have space-based origins. It’s ’cause they have a higher nickel content.)

And then, of course, the guy from Man At Arms made a replica of Sokka’s sword. He had to use extra steel because the meteorite material was too brittle, but it looks cool.

If not black.

In fact none of these blades are black. Meteorites look black after they impact because the outer layer of the rock forms a crust as it barrels through the Earth’s atmosphere. Simple erosion will wear that away, so making a sword out of it definitely will, too.


1. presumably the northern hemisphere’s winter solstice; I wonder if the creators even know my most recent winter solstice happened in June…
2. one small bonus is that the Moon appears bigger when it’s closer to the horizon. This is an optical illusion that happens in the real world.
3. To be honest, there are probably a lot of people with such a degree that might not notice, especially if their research focuses on stuff beyond our solar system, like quasars or whatever. 
4. I’m departing the country many years prior to this, but hopefully I will have at least one friend that will let me stay with them (and I have the actual money to fly all the way back to NZ…)

 

Here’s the Sun bing the wrong color again:

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