Everything that moves, moves supersonic if the speed of sound is 0. >I assume it's being compared to the speed of sound through Earth's air. That roughly 1.2

Everything that moves, moves supersonic if the speed of sound is 0. >I assume it's being compared to the speed of sound through Earth's air. That roughly 1.2 km/h in space that is nothing. Solar wind are like a 1.6 million km/h