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planet: late O.E., from O.Fr. planete (Fr. planète), from L.L. planeta, from Gk. (asteres) planetai “wandering (stars),” from planasthai  “to wander,” of unknown origin. So called because they have apparent motion, unlike the “fixed” stars. Originally including also the moon and sun; modern scientific sense of “world that orbits a star” is from 1640. (Online Etymology Dictionary)

Once upon a time, the people of ancient Greece and Rome thought the sun was a chariot of fire driven by the god Helios (or Sol to the Romans).  While we know this is not true today (and in fact, there is some arguement that it was not considered literally true then either), the planets of the solar systems go by names from Roman mythology (except for Earth and Uranus).  Mercury, Venus, Mars, Jupiter and Saturn were named by the Romans after the gods they thought they best fit–the bright and lovely Venus was named after the goddess of beauty and love while the red planet of Mars was named after the god of war. Uranus was discovered by William Hershel in 1781 (who tried to name the planet after King George III, but that didn’t stick) and eventually came to be known for Ouranous, one of the Greek protogenoi.  Neptune was discovered in the mid 1800’s and Pluto in 1930 before it was downgraded from planetary status in 2006.

We’ve been studying our solar system on and off since early summer (when I first started writing and researching this post–which is now three posts…), and we took a trip a few weeks ago to the Virginia Air and Space Museum.  For anyone in the Hampton Roads area, this is a great place to take the kids–it *is* a bit pricey (~$40 for the family), but they have a yearly membership for a family of four that is equivalent to going twice (this is pretty standard around here, since its a touristy place–most places have expensive one-time prices but really reasonable membership rates).  They have a number of interactive exhibits (a few of them were broken, but I’ve never been to a museum where that wasn’t the case) that are good for a range of ages.

And…they have a NASA Educator Resource Center (ERC).  If you are a homeschooler, scout leader, teacher, or just a parent with a kid that likes space, your area ERC is your friend.  They have free supplementary material on the space program, outer space and aeronautics-related math and science topics (also some good climate and weather stuff). And you don’t have to pay to go to the ERC if you aren’t going into the museum. On our trip, the kids got loaded down with several posters, a lithograph set of the solar systems, stickers, coloring books, etc.  They even got temporary tattoos of the NASA logo and had a chance to “drive” their remote controlled robot!

About the Solar System:

image from NASA

Our solar system is composed of eight planets orbiting a central star, the sun, which is  thought to be located some 26,000 light years away from the center of the Milky Way galaxy on the edge of Orion, one of the galaxy’s spiral “arms”.  The “size” of our solar system, as measured in the approximate distance from the Sun to Pluto (though it is not considered a planet, it is on the outer edge of our solar system and makes a good reference point) is some 3.67 trillion miles.  Because the scale of distances in the solar system are so huge, it can be difficult to visualize the placement of the planets, many classrooms (even college level astronomy classes) will use a sized-down model, such as this thousand yard model or to the scale of a football field (using the measurements from the above link, just divide the distances by 10)–the thousand yard model in particular makes a great physical fitness activity  .  Another resource that might help with the visualization of the scale of our planets and sun in relative size are the graphics on this site.  A few places, such as Ithaca, NY and St. Louis’s Delmar Loop even have “planet walks”–a to-scale walkway with markers for the planets (something else we can do while visiting at Grandma’s!).

Other solar system model projects can help kids learn the planets and their identifying features, as well as the orbits of the planets and the arrangement of our solar system.  To learn the names of the planets, we made up a song (which you can see in the above video of Chickadee at the  Virginia Air and Space Museum), or make a solar system collage or a model. One of my favorite 3-D models is this yarn/thread model from Art For Little Hands.  There are also a number of edible solar system projects available online, from this one using candies as planets to this cupcake and cake model.  We had a solar system snack using the cross-sections of different fruits and veggies–our sun was an orange slice and Mercury was a carrot slice, Venus a banana, etc. Other options include making a solar system model with play dough, cut outs, or coloring pages, or making your own movable model (fun fact: a moving model of the solar system is called orrery) or DIY home planetarium (this one looks like a good way to learn constellations).  Working models of the solar system are also available virtually and commercially–this website has a nice virtual one, while this site offers a solar-powered model.

Facts about the Sun:

Many cultures connect the sun with a deity, both as a god (such as Sol Invictus, Ra, Apollo) or as a goddess (Sunna, Ameratsu, Shapash) .  Solar myths may also include the idea of a barge/boat or a chariot transporting the sun.

The sun is type of star called a yellow dwarf, and it it is thought to be around 4.6 billion years old (our solar system is actually thought to have formed all at once ).  Hydrogen (~75%) and helium (~25%) are the main components of the sun (with another 0.1% “other”, heavier elements).  The sun is actually plasma, which may or may not be considered a fourth state of matter (plasma sort of like a super-ionized gas).

“The Sun’s plasma is so hot that the most energetic charged particles can escape from the Sun’s gravity and fly away, out into space. We call this plasma the solar wind because it blows out away from the Sun and past the planets, interacting with their magnetic fields and/or atmospheres. Along with the solar wind comes the Sun’s magnetic field, which reaches from the Sun out to past Pluto and Neptune.”
–for more information, check out NASA’s Themis Mission Information

This interaction of the solar wind and Earth’s magnetic causes a phenomenon known as the Aurora Borealis (in the Northern Hemisphere) and the Aurora Australis (in the Southern Hemisphere).  In astronomy, an aurora is the name given to a display of lights in the sky–named after Aurora, the Roman goddess of the dawn (Boreas, from which Borealis originates, is the Greek god of the North Wind). The aurorae are most easily visible the closer one gets to the polar region, though the Northern Lights have been seen as far south as Mexico.  Their activity depends on solar activity, and different colors appear in the sky , depending on the altitude in our atmosphere where the particles from the solar wind are energized.  NOAA (the US National Oceanic and Atmospheric Administration) maps the position of the aurorae by satellite and the Canadian Space Agency in cooperation with the International Space Station will start filming the Northern Lights from space on Thursday and you can watch the aurora live via their AuroraMAX program, if you don’t live somewhere without light pollution at the appropriate altitude.

The energy from the sun, of course, does more than make pretty lights in the sky (and as beautiful as they are, the phenomenon that causes the aurora has other effects for our planet as well).  Our sun is the engine that powers most of our climate (which creates conditions friendly to life) as well as the very web of life that we are all part of, via photosynthesis.  Our planet’s angle and orbit around the sun  determines the seasons that we experience. Even the level of species diversity found in different ecosystems is thought to be somewhat influenced by the sun.  There are many simple projects that can be done at home to illustrate the effects of solar energy.  For example, this activity offers a simple example of how the greenhouse effect works, most effective for pre-k to 1st or 2nd grade, while this activity shows how water can be purified using solar energy, or this variation which collects the water from vegetation (both of which are good survival skills to learn and an awesome lead-in to a discussion of the water cycle).

Solar system multimedia for kids:

Magic School Bus: Lost in Space (book) and Space Chase (online game)
Fetch! Solar System Episode
nineplanets.org for kids (awesome site)
NASA planet info cards
Khan Academy: Scale of the Solar SystemFormation of the Earth
Our Solar System by Seymoure Simon (Smithosonian book)
First Space Encyclopedia by DK books
Link list of solar energy projects (mostly geared towards older kids) from Build It Solar

**all images, unless noted otherwise, or pics of my kids (which should be obvious) are public domain from NASA and are available from their website**

Continue on to Part II