"A lie can travel halfway around the world while the truth is putting on its shoes." -- Mark TwainOn the whole, I think lies tend to be simpler than truths. If so, that might explain their relative "velocity". Lies spread faster than truths because they are easier to communicate.
Take the Theory of Evolution. Most of lies told about it can be expressed in a sentence or two. Most of the truths told to counter those lies require a bit more explanation. For instance, I recently came across a post on the internet that consisted of the assertion "human footprints found beside dinosaur tracks", a photo of the alleged footprints and tracks, and the question, "How can evolutionists disprove this evidence?"
Of course, "evolutionists" can indeed disprove that claim. But only by going into some detail about how the various marks were made. That sort of detail is at a competitive disadvantage with a lie that's just as pithy as a joke's punchline.
But do you think Twain is right? Do lies generally spread faster than truths? And if so, is it because lies are often enough simpler than truths, and therefore easier to communicate?