Information is ever-evolving. That's why there are new editions of textbooks, up-to-date encyclopedias, and good folks working tirelessly to constantly update Wikipedia pages (I'm NOT looking at you, Wiki-vandals). We're always learning new things, observing new phenomena, and doing new research. They used to teach that Pluto was a planet. I'm still salty about that changeover. Pluto was my favorite planet and I wanted to see it succeed. Kuiper Belt Object just doesn't have the same ring to it.
Keeping up with all the changes can be hard. That's why we have teachers and professors on the front lines of information, to keep us abreast of what we need to be kept abreast of. Sometimes, though, facts fall through the cracks, time marches on, and we forget that what we learned in middle school might not still be true. Redditors recently shared the false facts they've had to check themselves on over the years.