1 Today in Space News: Earth s oldest rock found on the Moon
2 Study Points Predict the approximate time of day/night you should look for first quarter moon, full moon, last quarter moon. Explain how astronomers think the Moon formed and give evidence. What causes a solar eclipse? What causes a lunar eclipse? What phase is the moon for each? Explain why the Earth undergoes seasons. Explain why it is hot in the summer. Explain why the Sun appears high in the sky during the summer but low in winter? What is included in the area of the sky known as the zodiac? What does the word zodiac mean? How many constellations are in the zodiac according to astronomy? What is the ecliptic plane? Where is the Sun in this plane? the Moon? the planets? the stars? What is meant by the Sun is in Leo? Explain why you only see some of the constellations of the zodiac at a given time. What is meant by the Earth s precession? Is Earth s precession a long or a short time? Explain why Polaris is the North Star? Explain why the stars appear to revolve around the North Star? Explain why the Sun is not in the constellation horoscopes say it is in when you are born. What distinguishes science from non-science? Give an example. Name the five North Circumpolar Constellations. Why are these important to us in MN? Define equinox and solstice? Sketch the Sun, Earth, and Earth s orbit. Draw Earth with the axis tilt and label the location of Earth at the solstices and equinoxes.
3 Moon Cycles of the Sky: Part 2 Moon Phases, Motions, Formation Lunar and Solar Eclipses Zodiac, Ecliptic Precession North Circumpolar Constellations Seasons
4 Origin of Moon* Early Earth and Mars-size object collide* Moon formed out of particles orbiting around the new collided Earth* Best explanation we have, but isn t perfect. Moon is made up of materials found in Earth s crust (outer layer) How the Moon was formed (1:56) Evolution of the Moon (after it formed) (2:41) Image:
5 Orerry with light Moon Phases
6 Lunar Eclipses only at Full Moon* If the Moon passes through Earth s shadow, we see a lunar eclipse.* Lunar Eclipse Earth blocks the sunlight from the Moon* If the entire surface of the Moon enters the umbra, the lunar eclipse is total. Cengage Learning 2014 Orerry with light
7 Size of the Sun & Moon from Earth From Earth the size of the Moon and Sun are about the same! The angular diameter of the Moon (~0.5 o ) is almost exactly the same as that of the Sun. This is a pure coincidence. The Moon s linear diameter is much smaller than that of the Sun.
8 Solar Eclipses only at New Moon* Orerry with light Due to the equal angular diameters, the Moon can cover the Sun completely when it passes in front of the Sun, causing a total solar eclipse.* Solar Eclipse Moon blocks Sunlight from Earth*
9 Solar Eclipses The Moon s shadow sweeps across the Earth, over points from where we can see a solar eclipse.
10 Total Solar Eclipse During a total solar eclipse, the solar chromosphere, corona, and prominences can be seen. Diamond Ring Effect
11 Solar Eclipse Types 1. Total 2. Annular 3. Partial 4. Hybrid (both total and annular) Types are due to the changing (angular) size of the Moon and Sun seen from Earth because the orbits are not perfect circles (they are ellipses). Wikipedia.com
12 Solar Eclipse Dates About 1 per year; max time is ~7 minutes. Next Total Solar Eclipse in USA (Texas to Maine): April 8, 2024 (2033 Alaska, 2044 MT & ND) Last Total Solar Eclipse across USA August 21, 2017 Best Pictures website link
13 Very Important Warning: Never observe the Sun directly with your bare eyes, not even during a partial solar eclipse! Use specially designed solar viewing shades, solar filters, or a projection technique.
14 Constellations Imaginary memory aids to describe sky 88 total constellations named in Earth s celestial sphere (previously 48 from Ptolemy about 350 BC) Currently used like stellar zip codes Other versions around the world Chinese, Arabic, Hindu, Native American Celestial Sphere
15 Constellations of the Zodiac Seen throughout the year because of Earth s revolution The zodiac constellations are located along the Sun s path on Earth (Ecliptic Plane).* Ecliptic Plane the plane of Earth s path around the Sun.* The zodiac region includes the Earth s path around the Sun, our Moon s path, & planets paths across Earth s sky.*
16 Annual Motion of the Sun The Sun is in Sagittarius on January 1 (sign of Sagittarius) The Sun is in Aquarius on March 1 (sign of Aquarius) The Sun is in Leo on September 1 (sign of Leo)* During the days of a given zodiac sign, that constellation isn t visible because it is behind the Sun, as viewed from Earth* Orerry with Sagittarius
17 Two Versions of Zodiac 13 Astronomical Constellations of the Zodiac (used by astronomers) and includes Ophiuchus* 12 Astrological Constellations of the Zodiac All 13 are in the ecliptic plane; Babylonians removed 1 to fit the 12 month calendar (and pretended they were the same size) Constellations One constellation missing from the traditional zodiac signs.
18 Precession of Earth Earth s Precession slow movement of Earth s axis because Earth is spinning* (traces out a circle as it changes) The Earth s North pole currently points to Polaris so we call Polaris our North Star, but the North Star will change.* Earth s axis of rotation points to the North Star and stars move around that point as the Earth rotates 3000 BC: North star = Thuban (5000 years ago) origin of astrology about 1000 BC, different sign dates (3000 years ago) 14,000 AD: North star = Vega 26,000 year cycle (long time)* Parke Kunkle s precession video (watch if you miss lecture) Precession wheel demo
19 What Sign Are you? Astrology is based on the locations of the constellations from about 3000 years ago when the constellations were visible at different times of the year than they are now.* Astrology is not a science; it is a belief system not testable or repeatable (science hallmarks: natural, testable & simple)* Astronomy uses the same names of constellations and uses all 13 constellations in the ecliptic You can look up your astrology sign based on the 13 sidereal constellations and accurate north star here: More about this from NASA here:
20 North Circumpolar Constellations Constellations visible year-round (mid-latitudes & north)* Minnesota and further north to the North Pole Don t rise or set; Visible all year and all night 5 North Circumpolar Constellations: Ursa Major (Big Dipper), Ursa Minor (Little Dipper), Cassiopeia, Draco, Cepheus* Globe & Celestial Sphere ov/apod/ap html
21 Seasons on Earth Caused by Earth s tilt which is about 23 degrees Northern summer = Southern winter Northern winter = Southern summer Globe
22 Seasons When the northern hemisphere is tilted toward the sun, it also experiences longer daylight. Longer daylight is the cause of higher temperatures in summer* The Earth s tilt causes longer daylight in one hemisphere Show longer daylight with globe & Sun is higher in the sky Northern Hemisphere Seasons Orerry Fall Winter Summer Spring Equinox: equal night and day* Equinox is when the Sun is crossing Earth s equator* Solstice: daylight is longest in each hemisphere* Solstice is when Earth s axis is tilted toward the Sun in one hemisphere*
23 Explanation with a friend Explain why the Earth undergoes seasons. Explain why it is hot in the summer. Explain why the Sun appears high in the sky during the summer but low in winter? Write your own explanation with the help of a classmate. Write 2-4 sentences to explain. This will help you understand what you learned today.
24 Observation Projects Earth-Sun Scaling, Lunar Eclipse Viewing Start: Jan. 17 Due: Monday! Planetarium (10 pts) Start: Today Due: May 14 Moon Phases Start Jan. 24 Due March 7 Sunset Part 1 Start Jan. 22 Due Feb. 19 Easiest way: Come with the class on Feb. 5
25 Homework Continue flashcards of STUDY POINTS Do D2L Brightspace Quizzes 1 &2 Earth-Sun Scaling OBSERVATION DUE Feb. 5 it by midnight (11:59pm) Work on Sunset Part 1 Observation due Feb. 19 Work on Moon Phases Observation due March 7 Lab arrive this week with the necessary materials Test 1 in 2 weeks: Tues, Feb. 12 To prepare: study points & 4 D2L Brightspace quizzes About 60 multiple choice questions. Bring a pencil. Optional bring a calculator (not graphing), some will be in the room to use