Facts

My son is really into memorizing facts, particularly about space and US Presidents. This provides me with thrilling opportunities to do things such as listen to someone yell a spitty list of all our solar system's dwarf planets into my ear for 2 to 3 hours at a time, which, judging from how often I do it, must be a hobby I really enjoy.

What's interesting about both history and space resources is they are full of "facts" that are no longer true. Because we have books and toys from different periods in time, some of them will say things like "Now, Bill Clinton is president" or... well, I don't know enough about Mars to write something that seemed true 10 years ago but now isn't. Pluto's existence is hotly contested by our toy bin, for example.

When I was in school, not in the dark ages but 20 years ago, we learned that there were 9 planets. There were 3 states of matter. There were 4 oceans. There were 2 genders. We learned these things as facts. 

It's still the same universe, but we just understand it better. We categorize it differently. Thankfully for all of us, we learned something in the last 2 decades. So now there are 8 planets, and 5 states of matter, and 5 oceans, and all the space-rocks and water and plasma are still where they were and what they were before. Nothing has changed except for our ability to better understand and describe things.

Don't be scared of learning new things and finding out that what you thought was a fact was, in fact, not.