But if dark matter is affected by gravity and does not undergo nuclear reactions, wouldn't much of it form black holes anyway?

Dark matter would attract other dark matter and cluster together, but instead of forming stars, just collapse in on itself?

They became a major space power. Obviously.

I used to agree but have since found out that the earth is actually slightly flatter than a sphere due to centrifugal force.

The problem isn't the hardness of the brush, but the dust. It is harder than any sufficiently lightweight material we could make solar panels out of.

Apparently brushing off the dust would just replace opaque dust with opaque scratches, if the panel isn't already sandblasted to hell to begin with.

Edit: The dust is electrostatically charged and clings to surfaces, so you can't easily tip/blow it off.