[tgflynn]

I don't think you'll find 0.2c relative velocities except near very energetic phenomena, especially not of things that are too small to easily see coming.

[skykooler]

Cosmic rays are far too small to easily see coming, and we get those all the time here.

[tgflynn]

I think it should be clear from the context that this discussion was about macroscopic objects. Cosmic rays don't carry the kinetic energy equivalent of a medium size nuke.