If there are many satellites orbiting earth, how do space launches not bump into any of them?
In: 2066
Space is *big*. And, more importantly, space *isn’t flat*.
If you’re drawing lines on a piece of paper, then, Euclidean geometry and all, any pair of lines which aren’t parallel *must* intersect. But this is *not* true in three dimensions. Pedestrian bridges go over roads, highways cross over other highways, metro tunnels run under city streets, etc. For two things to collide in space their trajectories have to intersect, and for *that* to happen, the two lines have to be more or less coplanar. I mean, what are the odds that 4 randomly chosen points in three dimensional space will *all* cleanly lie on the same flat plane? There’s also the matter of time: It’s not enough for two trajectories to intersect, the objects themselves have to both be at that shared point at the exact same time, quite literally down to the millisecond. If an object half a meter across is traveling at one thousand meters per second, then it has travelled twice its own diameter in a single millisecond. If two half meter objects are on a collision course at those speeds, then a delay of 0.001 seconds is all it takes to turn a hit into a [very] near miss, and real satellites are moving *a lot* faster than that. Once again, space is *big*, so the odds of two satellites bumping into each other are very very low.
…But *not* zero. [Collisions *do* happen](https://en.wikipedia.org/wiki/2009_satellite_collision), just not very often ([until it’s too late](https://en.wikipedia.org/wiki/Kessler_syndrome), anyway).
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