I think the general theory on Venus is that there was an impact with another body that caused it to start rotating the other way, albeit weakly.
Interestingly enough, astronomy textbooks don't usually refer to Venus as rotating the other way. Rather, they say that it is flipped 180 degrees, which as a result means it rotates the other way.
Interestingly enough, astronomy textbooks don't usually refer to Venus as rotating the other way. Rather, they say that it is flipped 180 degrees, which as a result means it rotates the other way.