Science in Science Fiction

Posted on 15 December 2010 by Mika

After listening to last night’s AGU Hollywood Panel, I have a few thoughts on the role of a science in science fiction.

Science in not in conflict with science fiction. Millions of stories happen every day, each one without violating the laws of science.

But all science fiction violates these laws. In the defunct advertising of the respell SyFy Channel advertising, the if of scifi was highlighted. This is the key to the genre: an exploration of how a story would play out in a world so slightly different from our own. The rules of science may remain consistent with our own, but something new is discovered (the physics of a highly oblate planet), or the social situation is different (a single-gendered society). Science fiction may explore a single, small yet vital change (the speed of sound is faster than the speed of light), or many major changes (faster-than-light travel, telepathy, aliens). Fundamentally, a science fiction story is a story of What if…?

Scientists can accept the needs of this genre, because that same curiosity about What if…? drives scientific research. Science is a field of curiosity and novelty. Every researcher is exploring the bounds of what we know, what we think we know, and what is completely baffling. The basis of the scientific method is that every theory must be falsifiable (must be capable of being proven wrong): scientists spend their days trying to prove the law of gravity is more of a suggestion, or that conservation of energy has an exception.

Call it a plot device, an exception, a What if, a gimme: if a story is compelling and the science consistent and plausible, even an audience of scientists will accept the downright breaking of the laws of science. Science fiction explores options, provokes imagination, and inspires dreams of a different future. This is fantastic!

Valid scientific critique of science fiction stories should not focus on story-necessary changes to science, but on small, story-irrelevant details that demonstrate sloppiness with science. Unobtainium, a fantastic mineral with unbelievable properties, is plot-necessary and acceptable (and the cheeky name is plausible if a geologist were to discover such a mineral!). The inaccuracy of attributing Hawaiian volcanoes to “gaps between tectonic plates” when it’s the farthest place on the planet from a tectonic boundary and “hot spots” is both more accurate and fits the dialogue pace is irritating. Watching a fictional scientific genius stumped by a high school physics problem breaks plausibility.

Plausibility is not the same as accuracy. Plausibility may borrow on statistically improbable events (impacts always hit Manhattan), or bend the laws of science (warp drive), but it is always internally consistent within the story (no deus ex machina technology) and when possible extends from real, legitimate science. The job of a science consultant is never to say “No, you can’t do that,” but to find a way to plausibly support the story they want to write.

In practice, plausibility is sometimes established during the conceptual stages, finding ways to support the story with plausible science explicitly presented in the script. More often, the plausibility is in the background, in the set, the special effects, and the property the actors interact with, telling the story of the the science in an alternate world for the curious scientist-fan. This is more common with the growth of fans who watch, re-watch, and screen-freeze scenes to capture all the details, and in the prevalence of websites dedicated to documenting errata.

Despite the initial motivation of increasing scientific plausibility in film in order to avoid criticism, for science fiction producers, the result of being careful with science is more compelling stories. Science is an endlessly fascinating subject, with real theories, observations, and consequences that seem more outrageous than fantasy. The adoption of science by mass media also helps science, where deviations from accuracy are compensated by presenting the field in a compelling, inspiring light that shapes the development of new technologies, and recruits future scientists. The relationship between science and science fiction is not one of conflict; it is mutually beneficial, and shapes a better future.

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Atmospheric Science of SG:A “Brain Storm”

Posted on 14 December 2010 by Mika

In Stargate: Atlantis, “Human,” our heroes are delivered to a secret facility in the middle of a desert, isolated from the rest of the world by a force field. Outside, the temperatures are hot, as expected in a desert. Inside the facility, the temperature radically drops (10 F in 10 minutes) as part of an experimental astro-engineering solution to climate change. When the force field collapses, dropping this isolated packet of incredibly cold air into the hot desert, what happens?

Astro-engineering Climate Change

Astrophysical engineering project from SG:A "Brain Storm."

In Brain Storm, the astro-engineering solution to climate change is to build an incredibly effective heat sink, then dump that heat in another, parallel universe. To stay on topic, I won’t get into the totally fun math that went into engineering their project, but the photo provides a hint.

The problem comes when the bridge gets out of control, and heat is drawn at a rapid rate with no cut off. This creates an enormous temperature unbalance of an incredibly cold (and getting colder) region.

At the Facility

The facility forms the eye of the event, the temperature unbalance around which all other weather is created. Because cold air is dense, the ai

Force field & wormhole sketch from SG:A "Brain Storm"

r around the facility is higher density, thus higher pressure than the surrounding region. Air is drawn down from above, and spreads out away from the facility along the ground. Because the temperature gradient is so extreme, the winds from high pressure to low pressure (from the facility to the rest of the world) will be incredibly intense. At extremely low temperatures, material behaviour changes substantially as more and more materials freeze, posing another hazard.

Oddly, the cold eye is the very best chance for clear skies, but I don’t think blue skies would be very reassuring in the circumstances.

Cold Front

Cold air is denser than hot air, so when the isolation ends, it will stay low, spreading horizontally along the ground in the ultimate cold front. As the denser air creeps along the ground, the wedge of cold air lifts hotter air, forming a low-pressure area. All temperature gradients sharpen along the front; with our already scifi-intense temperature difference, the unstable boundary between hot and cold air forms a field of tornadoes.

As hot air hits cold air, the dew point drops and water condenses (like your moist, warm breath forming fog on cold mornings). However, our secret facility is in a dry desert, without much water in the air to condense. If the facility had been along a coast, severe thunderstorms would form along the front. In the desert, dust is raised by the wind but otherwise the cold air is visually indistinctive.

A real-life cold desert is the Antarctic.

Hurricanes

Eventually, the cold front (and its associated lower pressure) will reach water. A hurricane forms when a low pressure zone over an ocean allows for hot air with moisture from sea spray rises, condensing into clouds and rain. The heat engine builds as long as it is over water, then even powerful storms quickly die off as they head inland and are cut off from the water supply.

If The Heroes Didn’t Save the Day

Of course, our heroes eventually save the day, shutting down the bridge to the parallel universe. But what if they’d failed?

With an extreme artificial temperature difference, the cold front would continue to spread, eventually creating a mega-storm unheard of even in disaster movies. Some of the background scientists got into an argument trying to figure out just how big the eye of the storm would eventually get, unable to apply normal techniques because the usual calculations based on temperature gradient suggest the eventual formation of a planet-wide storm with an eye larger than the circumference of the Earth!

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Like a Zircon in the Sky

Posted on 11 December 2010 by Mika

You’ve heard about the diamond stars before, at the very least in Beatles lyrics.

Turns out you can’t even trust stars to be real: recent observations have found a star with large amounts of zircon, more commonly known as a fake diamond. So next time you’re purchasing a star for a loved one, make sure to get it properly authenticated by your local astrophysicist/jeweler.

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The Cryptography of SG:U “Human”

Posted on 10 December 2010 by Mika

My apologies for the long hiatus — my thesis took over for a while, as did splitting off a new, science-only site GeoMika. It’s time to finish off posts that have languished for far too long in the “Drafts” folder. …like this one! Human featured a lot of specific cryptographic techniques, some problems modified to the Stargate universe, and a bunch of quantum computing.

As a mathematician trying to crack a code, Dr. Rush is faced with cryptography as an obvious symbol for his subconscious to project while communicating a mystery.

Cryptography is used to keep messages secret, so only the sender and the intended recipient can read it. An example is switching every letter to the number (1=A, 2=B, 3=C…): 18 21 19 8. Now, this is obviously pretty easy for someone else to figure out, so it isn’t very secure.

If two people meet in advance sometime, they can agree on an offset (switch every letter to a number, then add 4: 5=A, 6=B, 7=C…) which may be a bit more secure: 13 23. As long as the numbers can be uniquely transformed back to a single letter, the message sender and recipient can do all sorts of mathematical tricks to make things more complicated (Blowfish modulus 32, key Stargate: 89491420D9243D2A). Neal Stephenson’s Cryptonomicon does a great job of covering the history, techniques, and at-home cryptographical games up through World War II.

All of this is symmetrical-key encryption: both the sender and the receiver at some point have secure communications where they agree how the messages are going to be encrypted, and then either use the same key to encrypt and decrypt, or else keys that are clearly related so that if you knew one you could figure out the other. This has two problems:

  1. You need to have a secure meeting before you can have secure communication.
  2. You need a different pair of keys for every person you want to communicate with.

The common analogy is that Alice and Bob want to send secure messages. First, they need to meet, and both get identical keys to a padlock. Later, Alice puts her message in a box, and locks it with her key. She sends the box to Bob, who unlocks the box with his identical key. If they never met securely first, they couldn’t send messages later.

In 1976, this changed with the invention of asymmetrical public-key decryption. To work with the earlier analogy, Alice and Bob each have their own padlock with their own key. When Alice wants to send a message, Bob mails Alice his open, unlocked padlock. Alice uses Bob’s lock to close the box, and sends it to him: only he can open it with his key. Bob can use Alice’s open, unlocked padlock to close the box to send her a reply. In computer science, you encrypt messages using a public key, which only a private key can decrypt for reading.

To make things even more complicated, we could use factors as keys on encrypting and decrypting messages. Taking you back to high school algebra, factors are the numbers you multiple together to get a specific number. For example, the factors of 6 are: 1, 2, 3, and 6 (because you can multiply 1 x 6 = 6, and 2 x 3 = 6). If the only numbers you can multiply are 1 and the number itself, it’s a prime number (only 1 x 7 = 7, so 7 is a prime number). The bigger a number is, the harder it is to figure out what the factors are.

If you pick a very large number, multiply it by another very large number, you will produce an incredibly large number. Others would find it difficult to manually determine the factors of this incredibly large number, but it’s easy for you because you picked two of them in the first place to create the number! This is then used in generating the public key, so that only the person who knows the factors that were used (the private key) can decrypt the message. Classical cryptography assumes that factoring large numbers is computationally infeasible.

Cryptography has been making the news, where the methods to use brute force to break 256-bit encryption are summed up as either:

  1. Dedicated the computational power of the entire planet for millions of years to work on the problem, or
  2. physically beating the key out of the human who knows it.

This is pretty much accurate. If you want to explore using cryptography in your own communication, check out GPG (or its commercial equivalent, PGP). Just make sure you don’t lose your key!

This all starts going haywire with quantum computing, where suddenly problems like factoring huge numbers are feasible. Dr. Rush faces a classroom of his students while lecturing on Shor’s Algorithm, the technique for factoring extremely large numbers using quantum computers.

That’s the basic concept! If you’re interested, I’ll go into more detail about what exactly is going on in all those crazy boards, walls, and notebooks of math.

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Orbital Dynamics

Posted on 20 April 2010 by Mika

I love orbital dynamics. The math & physics is beautiful, complex, and precise.

I loved orbital dynamics when I first studied it as a wee physicist, but research into surficial cracks on Europa caught my heart and never let go.

Cassini’s mission is extended, and her dance to pull of another 7 years of orbits with less than a quarter tank of fuel is gorgeous.

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Melbourne: a disaster-movie trailer

Posted on 7 March 2010 by Mika

This week Melbourne, Australia had an intense, sudden storm, with huge hailstones (up to 10cm diameter observed) and enough rain to flood the downtown core. Although rare, this is not a unique event for Melbourne.

The cold southern oceans have what is called “infinite fetch” — because the ocean surrounding Antarctica is clear of any protruding landmasses, wind can drive waves higher and higher and higher without interrupting coastlines. This means you can get some nasty storms in the few places where land does start peeking into the flow — New Zealand, Tasmania and southern Australia, Cape Horn… — you can get some very nasty storms.

Melbourne is partly sheltered by Tasmania, by the shallow waters of the intervening continental shelf, and by the warm, large Port Philip Bay, but when a strong cold front comes in from the ocean and tangles with the hot, dry air from the interior, severe storms are born. (See pages 45-69 of The Cloudspotter’s Guide for more details on how cumulonimbus form — he writes such an elegant, beautiful description, I can’t hope to improve on it.) This means that sudden severe storms are not uncommon, with particularly severe events occurring approximately once a generation (the last flash flood in Melbourne was in 1972).

If you sliced open a hailstone, you’d see layers of ice, like coloured candy layers of a jawbreaker. A hailstone forms by being tossed up and down in the updrafts and downdrafts of convection within a storm, each trip adding a layer of ice and growing the hailstone. The larger a hailstone is, the more times it’s made the journey — the lemon-sized stones in Melbourne were tossed around quite a bit before pelting the city.

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The Length of a Day

Posted on 3 March 2010 by Mika

Spin in an office chair with your arms & legs sticking out, then pull your limbs in tight to spin faster. If you watched Vancouver’s Spring Olympics, you saw figure skaters slow down a spin by extending a leg, then speed up by simply withdrawing the leg. This has to do with the moment of inertia — the mass distribution impacts how an object will rotate. When more mass is farther out, things spin slower than when the same mass is closer to the axis of rotation.

When really big subduction earthquakes happen, a thick, heavy chunk of the ocean crust pulls in closer to the center of the planet. This redistribution of mass makes the Earth turn a little faster. After the Chile quake, our days are about 1.26 microseconds shorter than they used to be. This is a permanent change to our global moment of inertia.

But megaquakes aren’t the only impact on the length of a day — the moon provides a gravitational yank to slow us down. Over time, the moon is slowing the Earth through tidal friction, while simultaneously the moon is getting sped up by the Earth (conservation of momentum!), thus moving to a slightly higher orbit. Given billions of years, eventually days and months will be the same length, with the same side of the Earth always facing the same side of the moon. More details on this by the Bad Astronomer.

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The Geology of SG:U, “Air”

Posted on 28 February 2010 by Mika

As promised, this is a look at the chemistry and geology presented in the pilot episode of Stargate: Universe, “Air” (part 1, 2, 3). Our heroes are on a spaceship with a life support system with a non-functional filtration system, and need to come up with a way to sequester the carbon dioxide. They head down to a sandy planet in search of calcium carbonate.

“How come our heroes couldn’t just hold the Stargate open to a planet with a nice, tasty atmosphere?”
That would violate the defined functionality of the Stargate established earlier in Stargate: SG-1 and Stargate: Atlantis. The Stargates prevent the transport of individual molecules, which is handy when the teams connect to space-gates (vacuum on the far side) or submerged gates (water, water everywhere!).

“Wait, if the problem is too much carbon dioxide, how come they’re looking for calcium carbonate? Won’t that just mean they have even more carbon to deal with?!”
Yes, but no.

As carbon dioxide dissolves into water, the water becomes more acidic. Calcium carbonate dissolves in pretty much any acid, and slews of carbonate ions running rampant will form bicarbonate. So, if you chuck a bunch of calcium carbonate into water and add carbon dioxide, the calcium carbonate will dissolve in the acidic water, and all the ionized carbonate will form bicarbonate instead.

This is a well-known phenomena (see here for instructions on how to demonstrate it), and it’s an acceptable hypothesis that shell sediments in the ocean help buffer the acidity from increased carbon dioxide in the atmosphere (see here for an older summary of a Science paper on the topic), so it’s within the realm of plausible science to use the chemical reaction for science fiction.

“…if lime reacts with carbon dioxide to make calcium carbonate, and then calcium carbonate reacts with more carbon dioxide to make bicarbonates, why not start with lime?”
Our heroes didn’t manage to bring the medical-grade lime with them; very unfortunate. Yes, the system would be more efficient if our heroes made lime-enriched water and let that react happily away with the carbon dioxide because then it would sequester carbon twice over, but lime isn’t as easy for novices to identify via field test as calcium carbonate. Calcium carbonate comes as three minerals: aragonite, calcite, and vaterite. They are polymorphs — identical chemicals but different structure — so all of them dissolve in acid. The standard test is to add a drop of 10% HCl, and if it bubbles merrily away, you found calcium carbonate (or drop the rock in the acid for more bubbles!).

“I saw no bubbles. I saw red.”
Eh, red is prettier, or the geologist had prissier field gear because she’s used to alien atmospheres and walking around with acid could be dangerous, or maybe they used something that reacts to changes in pH by going red (cabbage juice turns red in acids (pH below 7), purple when neutral (pH = 7) and blue (pH above 7) or green (pH above 9) with bases), or in the rush to evacuate the base they left behind the hydrochloric acid and had to improvise from the material they had on hand.

“But wait! The chemical reaction is reversible with heat, so why did they hunt for rocks instead of just boiling their old life support goo on the planet?”
Eh, they couldn’t find a cauldron to hold it that didn’t dissolve into muck when handling the goo, or the goo had other chemical reactions going on (you need more than just “less carbon dioxide” to keep a human happy and the montage did include some prep of a white foam) and would do Very Bad Things when heated, or the Ancient goo wasn’t even using this particular chemical reaction to scrub carbon dioxide, or… ie, the chemistry is good and the concepts are good, and the details fall within plausible exceptions for science fiction.

“Why’d they go hunting for calcium carbonate in dried-up lakes or oceans?”
Limestone, chalk, and sea shells on Earth are all high in calcium carbonate; when faced with an alien planet and limited time, the hope that alien sea shells are chemically similar is both plausible, and gives some sort of constraint to guide our luckless heroes.

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Measuring the Speed of Light

Posted on 16 February 2010 by Mika

My chocolate is far too tasty to destroy in my non-existent microwave, but if anyone got anything chalky and kinda gross for Valentine’s, don’t fear! You can use that inedible cocoa-flavoured wax for at-home physics experiments!

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Twitter and Science Outreach

Posted on 3 January 2010 by Mika

I’ve been repeatedly asked why a serious scientist would use Twitter as a communication method. In addition to my interest as a disaster researcher, I am interested as a science outreach professional.

In my opinion, it is important to communicate both a passion for science and scientific knowledge in order to raise the scientific literacy of a society. This results in a more thoughtful society capable of making fact-based policy decisions, and which understands the value of funding scientific research. Effective science outreach also inspires new scientists to join the field, maintaining a constant supply of researchers to innovate new technologies and push forward the bounds understanding.

The majority of science is communicated through peer-reviewed professional journals. These papers mostly communicate discoveries only to other scientists, and rarely read by the general public. Summaries from press releases occasionally make it into mainstream news, often with enough distortion to upset or downright baffle the original researchers. In order to effectively communicate science to the public, it is the responsibility of scientists to actively engage in outreach efforts as part of their research. While select scientists use official broadcast platforms in the form of popular science books, radio or television shows, or blogs sponsored by publications or professional organizations, the lowest-cost way for a typical scientist to directly engage in outreach is to directly communicate with their community through participating in local events and using social networking tools. I use Twitter for the same reason I regularly give public lectures: it is my responsibility as a scientist to educate and engage with others about the joy of science.

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