This kind of visualisation is fascinating, but it’s also (for reasons I shall now explain) the root of a very serious misconception.
The misconception I speak of is the “junk in space” one. One sees images such as these and clearly reaches the conclusion that we’ve immersed ourselves in a thick fog of stuff which will soon become a barrier of fast-moving debris.
But... if one thinks about it, these objects are small, and if one were to lay them all out upon the surface of the earth, they’d actually cover a tiny fraction of it, and there’d be miles between each one. And furthermore, higher altitudes define a larger sphere, and surface area depends on the square of radius, so there’s actually far more distance available to these objects (alternatively, to repeat the experiment on earth, one would need to considerably scale down the already comparatively tiny objects and satellites).
And on top of that, we have a whole third dimension to deal with, so it’s not just one bigger sphere, but a continuum of spheres that all exist independently of each other.
Which leads to my core contention: even visualising satellites as the smallest graphical depiction possible (a single pixel) leads a viewer to vastly overestimate their size, and therefore the density of objects that exist in our sidereal neighbourhood.
What you did not consider is cascading collisions. If two high velocity objects collide, a large cloud of high velocity debris orbits Earth. The cloud expands and eventually parts of it collide with satellites, creating more debris that collides with other satellites, creating even more debris.
Oh no I understand that very well, I’m well versed in statistical mechanics. The thing is that the cross-section of the targets remain low, and therefore the amplitude of the scattering matrix remains pretty low. It’s actually pretty unlikely to successfully trigger off a divergent chain reaction. To use a nuclear analogy, it’s the density is well below a critical density (or rather, it’s far from a critical geometry).
