Our Galactic Neighborhood
Mercury is closest to the sun. Neptune is the farthest. Remember the order of the planets like this:
My Very Educated Mother Just Showed Us Neptune.
There's also a gross-out version:
My Very Early Morning Jam Sandwich Usually Nauseates.
Your mom and dad probably memorized something like this:
My Very Educated Mother Just Showed Us Nine Planets.
Why do you think it changed?
Why not make up one of your own?
Planets, asteroids and comets orbit our sun. They travel around our sun in a flattened circle called an ellipse. It takes the Earth one year to go around the sun. Mercury goes around the sun in only 88 days. It takes Pluto, the most famous dwarf planet, 248 years to make one trip around the sun.
Moons orbit planets. There are many moons in our solar system. Mercury and Venus don't have any moons. Earth has one. It is the brightest object in our night sky. The sun, of course, is the brightest object in our daytime sky. It lights up the moon, planets, comets and asteroids, too.