Modeling the Earth-Moon-Sun Relationship

Screen Shot 2014-10-28 at 12.11.38 PM

One of the trickiest, yet most important, Astronomy concepts for children to understand is the Earth-Moon-Sun relationship. The idea of rotation and revolution, while extremely basic, is the foundation of understanding motion in our solar system. These three objects have the greatest impact on our lives– the Moon orbits the Earth and the Earth orbits the Sun. The Earth rotates on its axis (once every 24 hours) and causes the Sun to rise in the east and set in the west. The moon orbits the Earth (once every 29 days, in respect to the Sun), causing lunar phases.

Having children construct a model is one of the best ways to help them understand these motions. You can purchase the activity here and have your child assemble the model below– you only need paper, scissors, and two brass paper fasteners.

OrreryPic

You can also have them act out these motions. Tell your child that you will be the Sun, she will be the Earth, and have her hold a ball (representing the moon). Then ask her to orbit around you, representing a year. Then she can add in the orbit of the moon around her (the Earth). Once she has these two motions down, she can combine them. You can ask her to try and fit  12 full revolutions of the moon around her, while orbiting the Sun only once– it gets a little tricky!

There are many ways to help your child understand the Earth-Moon-Sun relationship. Once they have the basics of rotation and revolution down, they are ready for season and lunar phases!

How To – Safely! – Observe The Solar Eclipse With Kids!

Eclipse Viewing with Kids

The chance to see an eclipse event in the sky is a wonderful opportunity to get  children excited about astronomy. On Thursday, October 23rd, millions of us in the United States will have the chance to see a spectacular partial solar eclipse. Unlike a total eclipse, only part of the sun is covered by the moon during a partial eclipse. The map below (from http://eclipse.gsfc.nasa.gov/eclipse.html) shows that unless you are in the extreme northeast of the country, you should have a view of the event.

eclipsemap

Safety First!

Never look directly at the sun with your unaided eyes, through binoculars or through a telescope– serious damage can occur. Sunglasses are not enough! You can find solar filters for binoculars and telescopes from many different sources. If you purchase a solar filter sheet, you can customize a filter for your own scope. You can also purchase a pre-made filter to fit the size of your scope. I prefer simple solar shades for eclipse viewing for children.

The most economical option is to make your own pinhole projector for viewing the eclipse. The quickest way is to take two sheets of stiff white paper and using a pin, poke a small hole in the center of one sheet. Aim the hole at the sun, and holding the other sheet behind it, move it back and forth until you get a good image.

pinholeprojectionpaper

Viewing Tips

The Solar Eclipse Explorer site from NASA is my favorite place to find specific eclipse times. After selecting your geographic area, you enter your city coordinates (latitude, longitude, altitude & time zone) and click on our current century. It will generate a list of eclipses for this century along with beginning, maximum, and ending times for your location. This is a great way to make sure that you are looking up at the right time! For those of us in the eastern part of the United States, the event will be cut short by the setting sun. Because the sun will be low in the western sky for most of us, it is important to find a vantage point  with a good view of the western horizon.

Helping Kids Understand

The best thing that you can do to prepare kids to view the partial solar eclipse is to help them understand the Earth-Moon-Sun relationship during this event. During a solar eclipse, the moon is between the earth and the sun. (This is different than a lunar eclipse, which is when the earth is between the sun and the moon.) A solar eclipse is when the moon blocks out the sun, from our vantage point here on the earth. A “partial” solar eclipse just means that the moon will not be blocking the sun completely at any point. Here is a great video of Bill Nye the Science Guy explaining eclipses.

eclipse

Having kids explore Earth-Moon-Sun motions in a kinesthetic way (with their bodies) really helps them understand these relationships. One great activity is to turn on a light source in a darkened room. A single light bulb works great– just take the shade off of a table lamp and draw the shades. Tell your child that his or her head is going to represent the earth, and have him hold an orange (or any spherical object) out in front of him to represent the moon. He can model the lunar phases by spinning around, holding the orange in front of him.  As he turns, he should see different portions of the orange lit up, representing the many phases. Then, have him stand with his head, the orange, and the light source lined up, so that the orange is directly between his head and the light. This represents the times when the moon is directly between the earth and the sun, during the New Moon phase. If the moon orbited the earth in the same plane that the earth orbits the sun, then we would have a lunar eclipse and a solar eclipse every month! But, the moon’s orbit is inclined about 5 degrees to the earth’s orbit. Twice a month, these orbital planes intersect– but not always during the right positions for an eclipse to happen. On average, some type of eclipse ends up happening about 5 times a year, but each can only be viewed in certain locations on the earth.

Go For It!

Eclipse viewing is such a great (and easy!) opportunity to share an astronomy experience with your children. As long as you are prepared for safe viewing, give it a try on October 23rd!

For more ideas on sky-viewing activities to do with your children, visit Stargazing with Kids.

Please note that the Amazon links are affiliate links, and if you do click through and purchase, I will receive a small commission.

sThe Eclipse

I stood out in the open cold
To see the essence of the eclipse
Which was its perfect darkness.I stood in the cold on the porch
And could not think of anything so perfect
As mans hope of light in the face of darkness.

– See more at: http://allpoetry.com/The-Eclipse#sthash.kD8GmEO9.dpuf

The Eclipse

I stood out in the open cold
To see the essence of the eclipse
Which was its perfect darkness.I stood in the cold on the porch
And could not think of anything so perfect
As mans hope of light in the face of darkness.

– See more at: http://allpoetry.com/The-Eclipse#sthash.kD8GmEO9.dpuf

The myth of Cassiopeia and Andromeda

The sky is full of constellations based on myths and legends from ancient cultures throughout the world. This is one reason that stargazing is important for children, and also something that makes it fun for them. The fall sky is full of a cast of characters from one of these ancient Greek myths.

Queen Cassiopeia and her daughter, Andromeda

Cepheus and Cassiopeia, king and queen of Ethiopia, had a beautiful daughter named Andromeda. While she was one of the most beautiful young women in all the land, Cassiopeia was sure that she was the most beautiful of all. Queen Cassiopeia, being a proud mother and boastful queen, declared Andromeda to be more beautiful than the nymphs of the sea. This greatly angered Neptune, the god of the sea. In his anger, Neptune sent a horrible sea monster to ravage the coasts of Cepheus’ kingdom. The only way that Neptune could be satisfied was for Cepheus to sacrifice his daughter to the horrible sea monster. Andromeda was thus chained to a rock in the sea, to be sacrificed to the monster.

At this time, Perseus was passing by after having killed the horrible Medusa. This great hero saw the beautiful princess chained to the rock. Perseus agreed to kill the monster in exchange for Andromeda’s hand in marriage. Cepheus and Cassiopeia agreed to this, and the great hero swiftly killed the monster and freed the princess. Perseus and Andromeda lived happily ever after, and all four characters (Perseus, Andromeda, Cassiopeia and Cepheus) are immortalized in the fall night sky.

Harvest Moon

harvestmoon The closest full moon to the autumnal equinox is called the harvest moon. The harvest moon is not necessarily bigger or brighter than a regular full moon. However, the moon’s orbital path is unique at this time of the year, and so it rises earlier than usual. Because of this, there is a shorter than usual time between sunset and the rise of the full moon, which means a nice, bright late evening sky.

Why does it look so big?

This is due to an optical illusion, the reason for which is still debated. Whenever the full moon is closer to the horizon, it appears to be much larger than when it is not. However, you can de-bunk this illusion very easily. Hold up a dime toward the full moon when it is near the horizon, and then a few hours later when it is farther up in the sky. You will notice that even though the moon appears larger when it is near the horizon, the dime will cover up the same amount of the moon in both positions. Another fun thing to try is to bend over and look at the full moon from between your legs. When you look at it from this position, it looks much smaller than when you look at it right side up!

Why is it called the “Harvest” moon?

Historically, the early brightness of this full moon helped farmers to gather their crops, despite the days getting shorter and shorter at this time of year. As the sun begins to set, the full moon rises, illuminating their fields. Save time on academic papers with research papers writer service. Today farmers rely on artificial lights to guide their tractors, but in the times before electricity, the harvest moon was a huge help.

Why do we have “seasonal” constellations?

If you’ve been visiting Lie Back, Look Up for awhile (or any other stargazing sites), you’ve probably been reading about the different constellations that you can view each season. You might also be wondering why we see different constellations each season. Understanding this explanation involves visualizing the Earth-Sun relationship in our solar system, as well as our solar system’s position in the Milky Way Galaxy.

It is helpful to remember that the stars are always up in the sky, we’re just not able to see them during the day due to the brightness of the sun. Without the sun shining during the day, we would be able to see the winter constellations during the daytime in the summer (and vice versa). Because the Earth changes position around the sun throughout the year, we get a different view of the stars in the Milky Way Galaxy during different times of the year.

Looking at the drawing above, you can see that on December 21st, we are able to see the stars in the constellation Gemini at night. We would not be able to see the stars of Sagittarius on December 21st, because they would be in the daytime sky. If you are looking to explain this to your kids, it is a great idea to “act out” the drawing above. Print out pictures of the constellations in the drawing and place them around the room. Use a basketball to model the sun in the center. They can rotate to experience day and night, and walk around the sun to model the orbit throughout the year. Have them stop in different positions throughout the year, and ask them which constellations they would be able to see at night. They will have to spin around in their position to face away from the sun, in order to view the nighttime constellations.

Where is the Big Dipper?

When most people are asked to identify one “constellation” in the night sky, their first answer is often the Big Dipper.  But, in fact, the Big Dipper is part of the constellation Ursa Major (the Big Bear), and is not an actual constellation by itself. The Big Dipper is what we call an asterism, which is an interesting and well-recognizable star pattern, while not one of the official 88 constellations. The Dipper can be found in many myths and legends, and is called by many names– including the Drinking Gourd and the Revolving Man. Regardless of what people have called it, it has been used throughout many cultures and many generations as a celestial tool for navigation. This is due to the fact that the Big Dipper can be seen year-round, and changes position in the sky throughout the year.

While most of us don’t plan on using the Big Dipper as a navigational tool anytime soon, it is helpful to know where to find it in the night sky throughout the year.

Here you can see that in the fall the Big Dipper is oriented like a spoon resting on the horizon, ready to catch the falling leaves of autumn. In the winter the Dipper is upright on its handle, like an icicle hanging down from the bowl. In the spring the Dipper is upside down, like it is pouring out heavy springtime rains; in the summer it is upright on it’s bowl, with the handle pointing up to the heavens.

The reason that the Big Dipper changes position like this is because in the northern part of the sky, all of the stars appear to rotate counterclockwise around Polaris, the North Star. Keep in mind that all of the stars “appear” to rotate in the sky due to the fact that the earth is rotating on its axis. Because the north pole is tilted towards Polaris, all of the stars in this part of the sky appear to rotate around this fixed point. This is why the Big Dipper appears to rotate around Polaris in a counterclockwise direction throughout the year.

The Big Dipper printable is available for you to download, with the drawing and seasonal explanation above.  Hopefully, this handy reference sheet will help you year-round while stargazing.

Stargazing in August

Check out our What’s Up in the Sky this Month page for an idea of planets and constellations to view in August.  Don’t forget to print off the free Summer Sky Map as well!  (I tried a new layout for the seasonal sky map– a circular view of the entire sky instead of just the southern view.  Let me know how you like it!)

If you’re looking for a good video about what to look for in the night sky, check out Stargazers.  This is my favorite place to go for weekly videos on what to see  in the night sky.

What is a shooting star?

If you’ve ever been lucky enough to see a “shooting star” in the sky, then you understand why they are the topic of so many songs and children’s rhymes.  Catching one with your eye feels like a special occurrence, maybe even a sign of good luck or good things to come.

But what exactly is a shooting star?  Is it a star falling out of the sky?  a dying star? a comet?  A shooting star is actually a particle from space colliding with the earth’s atmosphere.  We call these particles meteoroids, and they can be as small as a particle of dust or as large as a tennis ball.  As the earth travels around the sun, we run into some of these particles.  When they hit our atmosphere, they burn up and create a beautiful path in the sky, called a meteor.  The larger the particle, the more impressive the display.  If the particle does not burn up completely in our atmosphere, pieces might make it to the ground, which we call meteorites.

Several times during the year there are opportunites to see a large number of meteors during the night.  These events are called meteor showers.  This happens when the earth passes through the debris left from a comet traveling in a very elliptical orbit around the sun.  Because we know where these comets’ orbits are, we know exactly when we will be passing through their debris each year.  Stay tuned to Lie Back, Look Up for more information on viewing the Perseids meteor shower, occurring on the nights of August 11th and 12th.

Lie Back, Look Up: Why it’s important

Stargazing is a great way to “get outside” as a family.

 A back-to-nature movement to reconnect children with the outdoors is burgeoning nationwide.

—USA Today, November 2006

Many would agree that families are spending less and less time outside together.  Stargazing is a great way to get out and just enjoy the outdoors together– be part of this movement to reconnect children with nature.  Too many children don’t have enough experience outside at night, and stargazing can can help to conquer many of the fears that children have of the dark.

Gazing beyond the earth gives you perspective.

Part of the process of adolescence is for kids to begin to look beyond themselves.  We live in a world where children can explore their universe with a few clicks of a mouse, but the best way to gain perspective on their place in the universe is with their own eyes.  There is no substitute to gazing at the highlands and lowlands of the moon through a telescope, or looking at the Andromeda galaxy (2.5 million light-years away!) with the unaided eye.

Studying the sky is a great way to learn about other the history of other cultures.

From Galileo’s observations of the phases of Venus and the moons of Jupiter, to ancient farmers using the constellations to guide their crop planting, stargazing has had an important role for humankind throughout history. Learning about the mythology of the stars can be a great window into other cultures.  There are many books available on constellation mythology and endless websites dedicated to the topic. You can buy essays on the website any time.