Is it time to clean your mental closet?

We are in middle of moving here at Mama Joules' and let me tell you, it isn't pretty. I think the dust bunnies are conspiring with the ants to take over the place! It's no fun sorting through old papers, books, clothes, and more, trying to decide what to leave behind and what to take with us. But cleaning house is so important. Taking stock of what we have -- and what we believe in -- keeps us focused on what's really valuable.

Do you have any dated beliefs that might not stand up to current scientific thinking? I can think of a couple of things that I learned long ago about about outer space that have since been proven (or shown to be) false:

The nine-planet solar system is no more. Since Pluto was recently downgraded to dwarf planet status, we're now looking at a solar system with only eight planets.

However, new planets have been found outside of our solar system!

And several planets, not just Saturn, have rings around them.

So, I ask you today, what scientific beliefs are you keeping stored up there in the recesses of your mind? Should any of them be updated or thrown out?