Suppose there are just two satellites orbiting at the same altitude, a bit higher, let's say 5 orbits a day (ISS orbits 18 times a day, roughly). The two satellites cross each other's path twice per orbit. Over the course of a year, that's 3650 potential collisions. Given the length of their orbit might be 50,000 km, then the average distance between these two crossings is 13 km. Over 10 years, that reduces down to 1.3 km. Over 100, 130m. Over 100000, it's 0.130m. They are gonna collide.
Of course, I am assuming a few things, like their orbits don't decay, they aren't exactly synchronized (i.e. they drift, and will eventually cross every point on the other's), but also that the uneven gravity of Earth doesn't corral them into narrower orbital paths (which it absolutely will, increasing the chances of collision).
That's for only two satellites. There are literally thousands. And when they smash apart, they can each generate hundreds more killer-sized fragments.
Kessler syndrome is a very real possibility on a long timescale.
We should be more careful the junk we put in space.
Of course, I am assuming a few things, like their orbits don't decay, they aren't exactly synchronized (i.e. they drift, and will eventually cross every point on the other's), but also that the uneven gravity of Earth doesn't corral them into narrower orbital paths (which it absolutely will, increasing the chances of collision).
That's for only two satellites. There are literally thousands. And when they smash apart, they can each generate hundreds more killer-sized fragments.
Kessler syndrome is a very real possibility on a long timescale.
We should be more careful the junk we put in space.