The Skinny on Pluto

{an artist's creation of the new horizons spacecraft nearing Pluto... image credit via NASA}

Earlier this week on the space log, we talked about the planets in our solar system and how they are arranged in order from the sun. We learned about how something called a mnemonic device can help us remember things. We mentioned that while Pluto was included in our mnemonic, it is actually no longer considered a planet by many astronomers.

Pluto was discovered in 1930 by Clyde Tombaugh. At this time, it was thought to be larger than Earth. After years of studying space and better technologies with which to view things in space, astronomers were able to learn more about Pluto.

Pluto has a strange orbit, even intersecting the orbit of Neptune. It is also smaller than the Earth, not bigger (which Tombaugh originally thought). Pluto has a huge moon nearby, causing some folks to refer to it as a binary planet. When Pluto was first discovered, scientists thought it was alone. In the early 1990s, they started seeing other formations nearby that were almost as big as Pluto itself.

Space scientists from all over the world gathered in 2006 and decided on a formal definition of what a planet is. Pluto was then classified as a “dwarf planet.” Our new list of planets looks like this: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. No Pluto. Can you think of a new mnemonic to remember this list?

Remember This!

{Planets in order, minus Pluto image via Orderoftheplanets.org}

Have you ever heard of a mnemonic device? No, it isn’t that thing your doctor uses to hold down your tongue when you say “ahhh.” A mnemonic device is a little trick that helps us to remember something which we might not otherwise be able to remember. You might be wondering what this has to do with space or why we’re talking about it on the space log today. Well, one of the most well-known mnemonic devices has to do with space. More specifically, it has to do with the planets in our solar system and their order from the sun.

The planets are aligned in this order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune (& formerly Pluto…not considered a planet by some scientists & considered a planet by others). [For the purposes of this mnemonic, we will include Pluto but tune in for another blog post about the issues surrounding it!] Instead of trying to remember the planets’ names in the order they exist from the sun, it is much easier to remember a silly sentence. What makes the sentence a mnemonic is giving each word in the sentence the first letter of each planet, in their order.

The first letters of the planets in order are: M, V, E, M, J, S, U, N, & P. You can make up your own silly sentence or try one of ours: My very energetic mother just served up nine pizzas or Mary’s velvet elephant just sat under Nick’s porch. The examples are pretty much endless if you get creative. Another popular mnemonic is Roy G. Biv (each letter stands for a color in the spectrum as they appear to make up a rainbow…red, orange, yellow, green, blue, indigo, & violet). There are all kinds of silly mnemonics, but they can come in very handy when you are trying to remember something important.