Sometimes a movie comes out that represents certain concepts in physics, chemistry, or engineering, and the lay people look on in wonder and ask: “Is that really how it is?” This is about something more subtle than that. This is about the times that most people may not even notice that something is amiss.
Did you ever notice how every time there is a lab in a show or movie, there is inevitably a bottle or vial containing some blue liquid. I guess it is just because you would never find blue liquid under any other circumstances, so now people see it and think: “Oh, this must be a lab”.
Those were just the first three shows or movies that had labs (Amazing Spider-Man, The Flash, and Fringe) in it that I came up with off the top of my head. I have been working in labs for the last 9 years or so, and the first time I saw a blue liquid that was not simply blue dye in water was… last week. So if you walk into a lab, your likelihood of finding blue liquid – believe it or not – is quite low.
Sci-Fi Sky Colour
This usually occurs more in games (No Man’s Sky, I’m looking your way), where physics are usually not as important, and artistic license is the ordre du jour, but it still bugs me. The sky is blue. Most people do not ask why the sky is blue. I have mostly heard this question either coming from a child in their “why” phase (or a professor in a PhD defense… yes, I fully expect them to ask).
The short answer as to why the sky appears blue is that this colour results from a phenomenon called light scattering. Think of light as marbles on a table, and the earth’s atmosphere as small bumps in this table. The degree to which the marbles are deflected from their trajectory depends on their size, such that smaller marbles are deflected more than the larger ones, due to momentum. Light works the same way, but in this case, the size of the marbles corresponds to wavelength: the smaller the wavelength, the more light is deflected. The amount of deflection corresponds to the inverse of wavelength to the power of 4 -> (1/λ)4. Knowing that blue has the lowest wavelength of the spectrum, that is the colour we see in the sky. (Hyperphysics has a very nice article about that)
What does this mean for sci-fi worlds? If the sky is dominantly any other colour than blue, than you should see very little of the shorter wavelength colours anywhere. For example, if you see a sky that is predominantly green (around 500 nm), anything that is cyan to indigo should appear as black because there is so little of that colour in the light.
By the same token, if your sky is green – meaning there is no blue – and your plants are red – meaning they reflect red light – it means that only absorb green and yellow, which is not very efficient. The green we see in most plants stem (pun intended) from the fact that they absorb all red and blue light, leaving only green.
Science Works Fast
This is a very pervasive phenomenon, but its worst offender was Fringe. I really liked that series, but it perpetuated the myth of the super scientist: the person that is a genius at electronics, medicine, chemistry, physics, and all the spaces in between. I am fairly polyvalent in terms of scientific expertise; most people at my level of education are much more specialized. I can certainly imagine someone that has broader knowledge and interests than me, but a person can only know so much (for now. . .).
The follow-up of this is that when any problem appears, if you have the right person for the job (the super scientist), he can have it solved for you in a couple of hours. Do you know what happens in a couple of hours in a lab? Not much. If I give a synthetic chemist (someone good at making molecules) a specific target – even an easy one – give him the materials, and then wait a few hours. At best, he will be working on purifying the compound I gave him. More likely, he will be sitting at his desk waiting for his reaction to complete… these things take time, time to amount of intelligence will accelerate.