Connections: Investigating the Sun-Earth-Moon System

FOR THE FAMILY OF: INVESTIGATING CONNECTIONS Investigating the Sun–Earth–Moon System Craters on the moon retain their form because there is INSIDE THIS ISSUE! no erosion due to wind or Family Features: water. Copernicus crater is Sizing Up the Moon 2 relatively young—only 800 Family Features: million years old… Family Lunar Calendar 3 See story on page 2. Star Witness: Fred Espenak 4 Sky Watch: Eclipses 5 Sky Watch: The Moon at Your Fingertips 6 Cultural Connections 7 2 Family Features Sizing Up the Part 1: Predicting Moon 1 Remove the Play-Doh from one can. 4 Since the 50 pieces are probably not Roll it into a solid ball. exactly the same, put them in the center of the table and choose one, average Materials You’ll Need 2 Consult as a group/family about how sized piece. This piece represents the 2 cans of Play-Doh® big you think Earth is compared to the moon. 2 pieces of scratch paper moon. Then pinch off some clay and Butter knife for each participant form two balls that represent the rela- 5 Roll the remaining 49 pieces together tive size of Earth and the moon. This is into one large ball. This represents the Pencil your size prediction. Earth. Ball of string 3 Mark “Earth” on one piece of paper 6 Place this Earth next to your “predic- and “moon” on another. Place the ap- tion” Earth. Are they close in size? Most propriate ball of clay on each of these people tend to overestimate the size of pieces of paper. the Moon, so they end up with an Earth that is too small. 4 Place the Earth ball at one end of a table, and then decide, as a group/fam- 7 Our moon is approximately 30 Earth ily, where on the table to place the diameters away from Earth, so care- moon ball to represent the distance fully count, marking with your finger, from Earth to the moon’s orbit. This is 30 Earth diameters, one at a time. Or, your distance prediction. since the distance around a circle (the circumference) is pi x diameter, and pi Part 2: Modeling is about 3, estimate 30 diameters by 1 Open the other can of Play-Doh. Roll it wrapping a piece of string around your Birthday Moons out into a hot-dog shape. Earth 10 times. Unwrap it, and stretch Ever wonder what the phase of the 2 Cut it into 5 equal pieces. it out from Earth. Then place the moon moon was when you (or a friend or at the other end of the string. Was your family member) were born? What 3 Cut each of these pieces, in turn, into distance prediction close to the actual phase will it be on your next birthday? 10 equal pieces. You should now have distance? Go on the Internet to find out: 50 more or less equally sized pieces. Hot http://tycho.usno.navy.mil/vphase.html Links [http://stardate.org/nightsky/moon/ ] On the Cover Craters on the moon retain their form because there is no erosion due to wind or water. Copernicus crater is relatively young—only 800 million years old—compared to the rest of the lunar surface that formed some 4 billion years ago. This image was taken by the Apollo 17 orbiter. Copernicus is a large crater, measuring 93 km (55 mi.) across and 3.8 km (2.3 mi.) deep. This crater also has a raised rim, and you will notice that large blocks of material along the edge have slumped downward, form- ing terraces. Unlike Barringer Crater on Earth, Copernicus has three isolated mountains in its center, each one over 1,000 m tall. Exploring such a crater would be dif- ficult to do on foot or in a vehicle, as the bottom of it is filled with a rough and jumbled mass of rock! (Credit: NASA) A Family Lunar Calendar 3 Along with many Native American What to do calendars, the Moslem, Jewish, Hindu Consider the list of calendar names Discuss events that are significant and Chinese calendars in use today are from two different Native North to your own family that may or may all based on lunar cycles. (The Chinese American groups. The Cheyenne lived not be linked to the climate. Then calendar is by far the oldest of these, on the plains of the central part of brainstorm some ideas for what you believed to date back to 2698 B. C.) America, and the San Juan Pueblo is might call each month and create a Lunar calendar months begin with the in the high desert mountains of New calendar that is unique to your fam- new moon or the first sighting of the Mexico. By looking at the names for ily. (For example, does your family crescent moon after the new phase. their months, you could make some have multiple birthdays in January? Because the moon goes through one guesses about the differences in Perhaps the January moon would be- complete set of phases in 29.5 days, a climate for these two regions. come the Birthday moon. Do you take lunar month does not quite match our a family vacation in the same month modern calendar. There are similari- each year? ) ties, however. Just as months on our calendar have unique names, each lunar month had a name based on either a religious significance or a natural change in the season. Modern Almanac Cheyenne San Juan Family Calendar Calendar Calendar Pueblo Calendar Month Month Month Calendar Month Month January Winter Moon Hoop and Stick Ice Moon Game Moon February Trapper’s Moon Big Hoop and Coyote Frighten Stick Game March Lenten Moon Light Snow Lizard Moon Moon April Planter’s Moon Spring Moon Leaf Split Moon May Milk Moon Time When Horses Leaf Tender Get Fat June Rose Moon Moon When Leaf Dark Buffalo Bulls Rut July Summer Moon no name Ripe Moon August Dog Days Moon Time When Wheat Cut Cherries are Ripe September Harvest Moon Cool Moon All Ripe Moon October Hunter’s Moon Moon When Water Leaf Fall Moon Begins to Freeze on the Edge of the Stream November Beaver Moon Freezing Moon All Gathered Moon December Christmas Moon Big Freezing Moon Ashes Fire Moon 4 Credit: F. Espenak Star Witness pale in comparison to the images of the Fred Espenak, event that were burned into my mind’s aka Mr. Eclipse eye. I knew that I just had to see another Even though there are countless places eclipse because it all happened way too to visit and wonders of nature to see on fast. Before my equipment“ was even Earth, Fred Espenak believes that every- packed into the car, I was already dream- one should have “witnessing a total solar ing about traveling to Quebec for the total eclipse in 1972! eclipse” on their list of things to do be- and reactions during totality range from fore they die. Part of his job at NASA’s You might think, “once you’ve seen one, applause to tears. Mr. Espenak explains Goddard Space Flight Center involves you’ve seen ‘em all,” but Mr. Espenak it this way: Think about something that calculating the details of eclipses, from would disagree with you. Because of the you would love to do, like exploring the how long they will last to where on Earth circumstances of solar eclipses, they are Grand Canyon, or gazing at the Mona the eclipses will be visible, for both NASA only visible from a narrow band along Lisa, and then imagine that you could and the International Astronomical the surface of the Earth. Fortunately, Es- only do it for 2 minutes every 2 years! Union. His related hobby is traveling the penak loves to travel. He’s been to every You would definitely savor the experi- world to photograph and experience continent on the globe, including Ant- ence. You would look forward to your first hand these natural wonders. He got arctica, just to experience solar eclipses next chance with great anticipation. As hooked on the pursuit of eclipses while in the regions where they’re viewed best. for solar eclipses, will the weather will still in high school. In Mr. Espenak’s own To date, he’s seen 20. If you’ve only seen cooperate, or will the clouds force you to words, this is how it all got started: a partial solar eclipse or a lunar eclipse, wait for the next one? you may question Mr. Espenak’s pas- In 1970, I was a high school student Of the 20 total eclipses that he’s seen, so sion. But this is his response. and an amateur astronomer so I thought far, Mr. Espenak has two favorites. His “that the solar eclipse passing along the On a scale of 1 to 10, a partial solar first, in 1970, was wonderful, because east coast of the U.S. would be a once- in- eclipse is interesting, and he’d rate it a 6. he didn’t know what to expect and that a-lifetime experience that I couldn’t pass An annular eclipse is a special case, as is where he caught the eclipse-chasing up. I convinced my parents to loan me it’s not quite a total, but is not like a par- bug. The total eclipse in 1991 was also their car for the 500-mile drive, in spite tial, either. During an annular eclipse, stunning, with totality lasting over 6 of the fact that I’d only been driving for a the Moon is a bit too far from Earth to minutes.

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