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Explain xkcd: It's 'cause you're dumb.
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Orbital Mechanics
To be fair, my job at NASA was working on robots and didn't actually involve any orbital mechanics. The small positive slope over that period is because it turns out that if you hang around at NASA, you get in a lot of conversations about space.
Title text: To be fair, my job at NASA was working on robots and didn't actually involve any orbital mechanics. The small positive slope over that period is because it turns out that if you hang around at NASA, you get in a lot of conversations about space.

Explanation

Randall roughly plots how high school physics, undergraduate-level physics and a job at NASA somewhat increased his knowledge of orbital mechanics. But this learning was apparently nothing compared to the "direct" experience of playing with the Kerbal Space Program, a rocket building and piloting sandbox game.

Orbital mechanics can be somewhat counterintuitive. The art of changing orbits involves relative velocities, positions, and times in complex interactions. As soon as you try deviating from a perfectly regular orbit, or start having to deal with N-body problems and orbital resonances, you have to coordinate your movements in possibly in counterintuitive ways. One example is just, if you want to reach an object ahead of you at the same orbit you have to brake to reach a lower orbit. At that lower orbit your velocity is faster and you can overtake that object in front. After that maneuver you have to accelerate for increasing your orbit high and reducing your speed matching your target.

At the title text Randall admits that at the time when he did work at NASA he was not involved in orbital mechanics — which is also true for the most other NASA employees — but everybody was talking about this without a significant increase of knowledge.

The Kerbal Space Program was featured as one of the frames in the 1350: Lorenz April Fools project and in 1244: Six Words.

Transcript

How Well I Understand Orbital Mechanics:
[There is a graph with the x-axis labeled as 'time' increasing to the right. The y-axis is unlabeled but it can be assumed that it could be labeled 'understanding'.]
The line stays flat until the first bump, which is annotated "Took High School Physics".
The line decreases, then grows to a higher maximum with the annotation "Got Physics Degree".
There is a small amount of decrease until a gradual bump in the graph labeled "Actual Job At NASA".
It gradually decreases to pre-NASA levels, but then begins to increase exponentially. The annotation reads "Started Playing Kerbal Space Program".

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