@NeolibMICDemon@krautfarmer@dirtman starlink satellites already actively manoeuvre to avoid other satellites with only 10,000 of them up there. So with 1,000,000 the chance of a collision is almost certain. Large satellites like starlink remain visible throughout the whole night where most observations occur.
@NeolibMICDemon@krautfarmer@dirtman High likelihood that they start crashing into each other, creating a chain reaction of collisions, releasing an exponential about of debris (kessler syndrome). As well as creating so much light pollution make earth-based astronomical observations near impossible.