Eclipse Basics
What Are Eclipses?
Eclipses are all about shadows. They occur when one object (planet, Moon, etc.) moves in front of another. The other object moves into the shadow of another object. In the Sun-Earth-Moon system, eclipses occur whenthe Sun, Earth and Moon all line up. In astronomical terms, this is called “syzygy,” a word derived from Ancient Greekthat means “yoked together.”
Total Solar Eclipses
Eclipses of the Sun occur when the New Moon passes between the Earth and Sun. When the Moon covers theentire disk of the Sun, we see a total eclipse of the Sun with the corona glowing. During the eclipse, the Moon’s shadow is cast upon the Earth and travels across the surface at more than 1,000 miles per hour. From startto finish, a solar eclipsetakes a couple of hours. Most of the time, the sky is bright. The Sun continues to shine in the sky. You need eye protection the entire time when only part of the Sun is covered by the Moon. When the Sun is completelycovered – during totality – it’s safe to view the Sun’s corona without eye protectionfor a short time. Totality lasts only a few minutes. The longest total solar eclipses last just over 7 minutes. The totaleclipse of the Sun on August 21, 2017 lasted up to 2 minutes and 40 seconds, depending upon where you were.
Partial Solar Eclipses
People inside the shadow’s path see a partial solar eclipse if they are in the penumbra of the Moon’s shadow, anda total solar eclipse if inside the umbra (see diagram below.) Only part of the Sun is covered during partial eclipse.You need eye protection the entire time during the partial phases of an eclipse.
Lunar Eclipses
Eclipses of the Moon occur when the full Moon passes through the shadow of the Earth. Everyone on the nighttime
side of the Earth can view a lunar eclipse. When the Moon passes through the central partof the Earth’s shadow—the umbra—it will dim to a dark red color. Like red skies at Sunset, the Earth’s atmospherebends the redderlight into the Earth’s shadow. During lunar eclipses, the Moon is illuminated with this red light.
Lunar eclipses last for several hours as theMoon moves through the Earth’s shadow. It is completely safe to view the Moon.
Why Don’t Eclipses Happen Every Month?
Eclipses only happen when the Sun, Moon and Earth all line up, at syzygy. The Moon’s orbit is tilted about 5degrees from the plane of the Earth’s orbit around the Sun. The lunar orbit crosses the plane of Earth’s orbit in twoplaces called nodes. Most months, the lunar orbit carries the new Moon above or below the Sun, and so there is nosolar eclipse. The same is true for lunar eclipses: most months, the lunar orbit carries the Moon above or below theshadow of the Earth, and there is no lunar eclipse. Solar eclipses happen when the new Moon occurs near a node ofthe lunar orbit. Likewise, lunar eclipses happen when a full Moon occurs near a node.
Name ______
Eclipse Basics Worksheet
1. An eclipse is all about…
a. Moon phases.c. shadows.
b. Moonshine.d. sunlight.
2. For there to be an eclipse, one object moves in front of another and the other object moves into the shadow of the first.
a. Trueb. False
3. Eclipses occur when the Sun, Moon, and Earth all line up.
a. Trueb. False
4. A solar eclipse occurs when the ______phase passes between the Earth and Sun.
a 1st Quarterc. Full Moon
b. Gibbous Waxingd. New Moon
5. During a total solar eclipse we see the Sun’s ______.
a. chromospherec. photosphere
b. coronad. sunspots
6. During the total eclipse of the Sun on August 21, 2017, the total eclipse phase last up to…
a. forty-five seconds.c. two minutes and forty seconds,
b. one hour.d. two hours.
7. If people are in the penumbra of the Moon’s shadow, they see a(n) …
a. annular eclipse.c. partial eclipse.
b. lunar eclipse.d. total eclipse.
8. You need to have eye protection during the entire time during the…
a. annular eclipse.c. partial eclipse.
b. lunar eclipse.d. total eclipse.
9. A lunar eclipse occurs when the ______phase passes into the Earth’s shadow.
a 1st Quarterc. Full Moon
b. Gibbous Waxingd. New Moon
10. When the Moon enters the total eclipse phase, the Moon will appear…
a. black.c. dark red.
b. dark orange.d. grey.
11. A total lunar eclipse can last for…
a. 15 minutes.c. several hours.
b. a half hour.d. two days.
12. You must have eye protection to observe a lunar eclipse.
a. Trueb. False
Eclipse Basics Worksheet – Key I
1. An eclipse is all about…
a. Moon phases.c. shadows.
b. Moonshine.d. sunlight.
c. shadows
2. For there to be an eclipse, one object moves in front of another and the other object moves into the shadow of the first.
a. Trueb. False
a. True
3. Eclipses occur when the Sun, Moon, and Earth all line up.
a. Trueb. False
a. True
4. A solar eclipse occurs when the ______phase passes between the Earth and Sun.
a 1st Quarterc. Full Moon
b. Gibbous Waxingd. New Moon
d. New Moon
5. During a total solar eclipse we see the Sun’s ______.
a. chromospherec. photosphere
b. coronad. sunspots
b. corona
6. During the total eclipse of the Sun on August 21, 2017, the total eclipse phase last up to…
a. forty-five seconds.c. two minutes and forty seconds,
b. one hour.d. two hours.
c. two minutes and forty seconds
7. If people are in the penumbra of the Moon’s shadow, they see a(n) …
a. annular eclipse.c. partial eclipse.
b. lunar eclipse.d. total eclipse.
c. partial eclipse.
8. You need to have eye protection during the entire time during the…
a. annular eclipse.c. partial eclipse.
b. lunar eclipse.d. total eclipse.
c. partial eclipse.
9. A lunar eclipse occurs when the ______phase passes into the Earth’s shadow.
a 1st Quarterc. Full Moon
b. Gibbous Waxingd. New Moon
c. Full Moon
10. When the Moon enters the total eclipse phase, the Moon will appear…
a. black.c. dark red.
b. dark orange.d. grey.
c. dark red.
11. A total lunar eclipse can last for…
a. 15 minutes.c. several hours.
b. a half hour.d. two days.
c. several hours.
12. You must have eye protection to observe a lunar eclipse.
a. Trueb. False
b. False
Eclipse Basics Worksheet – Key II
1. c
2. a (2 choices)
3. a (2 choices)
4. d
5. b
6. c
7. c
8. c
9. c
10. c
11. c
12. b (2 choices)
Eclipse Basics Worksheet
Scoring Guide
12 – 411 – 3.5
10 – 3
9 – 2.5
8 – 2
7 – 1.5
6 – 1
1-5 – .5
0 – 0
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