Quote Originally Posted by Big King Sanctaphrax
Why is that? It's always perplexed me. The propellors, I mean.
Time dilation. The tip of the propellor blade is moving faster than the middle, because it has a biger circle to go through. So according to relativity it actually moves backwards in time relative to the hub. The difference is quite small, of course, so the propellor seems to go backwards slowly.