Just how many planets are there?
Being a science geek, I’ve always been intrigued by not only maps as a young child, but also our solar system. Now I wasn’t very big into Jules Verne, Isaac Asimov or Karl Sagan, but I enjoyed reading about the planets of our solar system.
Recently, however (as in the past 4 or 5 years), a flurry of activity has been happening regarding our solar system. For instance, a new planet and moon were discovered in 2003, named Xena and Gabrielle, after the television-series characters of the same name. (According to this article.)
Recently, the planet-moon duo has been renamed Eris (the planet) and Dysnomia. They’re way out beyond Pluto. Now, when they were discovered, scientists had to come up with a new way to classify planets because Eris was so small. Since its diameter is only roughly between 1,490 to 1,860 miles, they decided to call it a “dwarf” planet. Now here comes the rub.
Pluto, our ninth planet, is only 1,430 miles across. Therefore, it stands to reason that they couldn’t leave Pluto classified as a “regular” planet. So, after hundreds of years of having nine planets, Pluto got demoted to “dwarf” - now we only have eight “normal” planets.
As a kid in elementary school, I learned this mnemonic (although I didn’t know what it was) to remember the planets: “My Very Educated Mother Just Served Us Nine Pies.” NOW what are the kids going to use to remember the planets??
Oh, one other thing, we also have a “dwarf” planet between Mars and Jupiter named Ceres. It was discovered in 1801 and thought to be a “big” planet at 530 miles wide. However, it was downgraded to “asteroid” once the other asteroids in the Asteroid Belt were discovered. Now, as I understand it, it has been promoted to “dwarf” planet.
So here’s a mnemonic to remember all these planets:
My                                      Mercury
Very                                    Venus
Excellent                           Earth
Mother                              Mars
Could                                 Ceres
Just                                    Jupiter
Serve                                Saturn
Us                                      Uranus
Nine                                   Neptune
Pizzas                                Pluto
Eventually.                        Eris






