[piytar]

That used to bug me, too, but there is an explanation. In the Star Wars fictional universe, the Kessel run involves going through an area with a cluster of black holes that warp space. Depending on the path through the cluster, the distance differs. Only a really powerful hyperdrive permits one to take the shorter paths without getting sucked into a black hole. Thus, the distance for the Kessel run is shorthand for how powerful your ship’s hyperdrive is.

Not sure if this is cannon though.

[ctdonath2]

The term you’re looking for is “head canon”: an explanation that makes complete sense to you, even if it’s not official.

[Vince Ferrer]

That used to bug me, too, but there is an explanation. In the Star Wars fictional universe, the Kessel run involves going through an area with a cluster of black holes that warp space. Depending on the path through the cluster, the distance differs. Only a really powerful hyperdrive permits one to take the shorter paths without getting sucked into a black hole. Thus, the distance for the Kessel run is shorthand for how powerful your ship’s hyperdrive is.

Not sure if this is cannon though.

The explanation is that the writer didn't know what he was talking about and had to make something up later when people pointed out his flaw.