I Celestial Observations A Celestial Object Any object
I. Celestial Observations A. Celestial Object- Any object in space (outside Earth’s atmosphere) Examples: moon, planets, stars, sun B. Celestial Sphere- Model of the sky 1. zenith- highest point in the sky directly above the observer’s head 2. horizon- imaginary boundary between the sky and the ground.
C. Location on the Celestial Sphere- THE HORIZON SYSTEM 1. Altitude- Angular distance above the horizon
II. How do we know Earth revolves around the Sun? Summertime/Wintertime Constellations
How do we know Earth Rotates each day? 1. The Foucault Pendulum 2. The Coriolis Effect
III. Rotation- The spinning of a celestial body (Earth) on an imaginary axis 1. Earth’s Direction of Rotation: West to East 2. Angular Rate of Rotation: THINK- one complete rotation a. 360 degrees b. 24 hours c. Rate= 360 / 24 = 15 degrees per hour
B. Effects of Earth’s Rotation 1. Day and Night
6 AM Sun 8 AM 4 AM 10 AM 2 AM noon midnight 2 PM 10 PM 8 PM 4 PM 6 PM
2. Apparent Motion of Sun a. Earth rotates from West to East b. sun “appears” to move in arc from East to West
Changes in the Sun’s Apparent Path Throughout the Year Date Common Name Sun Rises Sun Sets Direct Rays N. Y. S. Daylight September 21 Autumnal Equinox Due East Due West Equator 12 December 21 Winter Solstice S. of Due East-West 23 ½ SOUTH Less March 21 Vernal Equinox Due East Due West Equator 12 June 21 Summer Solstice N. of Due East-West 23 ½ NORTH More
3. Apparent motion of the stars
b. The apparent daily motion of celestial objects (like stars) changes when the observer’s Latitude on Earth changes. At 90 degrees North. NO stars rise or set At 0 degrees (Equator)- ALL stars rise or set At 43 degrees (NYS)
Effects of Earth’s Revolution 2. Position of the Big Dipper (and other circumpolar constellations) changes position in yearly cycle. 4 2 3 19 Location of observer – NYS Time of Day Position of the big dipper
c. The apparent daily motion of the Big Dipper, a Circumpolar constellation. d. Star Trails a time-exposed photographic image that shows the apparent motion of stars; it appears as a blurry line across the film. Angle of arc measured with a protractor is 60 degrees Time exposure = 4 hours
Changes in the Sun’s Apparent Path Throughout the Year Date Common Name Sun Rises Sun Sets Direct Rays N. Y. S. Daylight September 21 Autumnal Equinox Due East Due West Equator 12 December 21 Winter Solstice S. of Due East-West 23 ½ SOUTH Less March 21 Vernal Equinox Due East Due West Equator 12 June 21 Summer Solstice N. of Due East-West 23 ½ NORTH More
Changes in the Sun’s Apparent Path Throughout the Year Date Common Name Sun Rises/Sun Sets Direct Rays Noon-time Sun N. Y. S. Dayligiht September 21 Autumnal Equinox Due East/West Equator South – mid 12 December 21 Winter Solstice South of East/West March 21 Vernal Equinox Due East/West June 21 Summer Solstice North of East/West 23 ½ South – low Equator South – mid 23 ½ North South - high Less than 12 12 More than 12
E. Models of the Universe 1. Geocentric Model 2. a. About 2000 years ago, the Greek astronomer, Claudius Ptolemy developed a detailed model of the universe based on the idea of revolving spheres. b. In this model of the universe, Earth was the center, and all heavenly bodies moved around the Earth in perfect circles. c. Ptolemy’s geocentric model, as illustrated on the next page, can be summarized as follows: 1. Earth is located in the center and does not move. Claudius Ptolemy 100 -178 A. D. 2. The stars are located on a transparent sphere that rotates once each day from east to west around Earth.
3. The sun, the moon, and each planet are carried by separate spheres also rotate from east to west around Earth. 4. Each planet is located on an “epicycle” that also rotates. So as each planet moves around Earth, it is also moving on its epicycle. (this is why the planets seem to move backwards compared to the stars when you observe them for several weeks) d. This model was accepted for almost 1400 years because it explained celestial observations made from Earth and it 39 seemed so obvious
E. F. The geocentric model does Not explain terrestrial (Earth) observations such as: 1. The movement/rotation of a pendulum is direction 2. The curvature of the paths of projectiles, winds, and ocean currents
2. Heliocentric Model a. In the 1500’s, a new model of the universe was proposed in a book by the Polish astronomer Nicolas Copernicus. b. In this model of the universe, the Sun was the center. c. Copernicus’ heliocentric model can be summarized as follows: 1. The Sun is located in the center of the system and does NOT move. 2. The stars are located on a stationary/unmoving transparent sphere. The sphere is a great distance from the sun. 3. The planets move in circles around the sun. Nicholas Copernicus 1473 -1543 A. D. 4. The moon moves in a circle around Earth. 5. Earth rotates on its axis from west toward east each day.
d. Copernicus’ heliocentric model does NOT explain the apparent cyclic variations in the size of the sun, and the cyclic variation in the orbital speeds of the planets. This is because in Copernicus’ heliocentric model, the planets orbit the sun in perfect circles. 3. Heliocentric Model (2 nd Version) a. In 1609, Johannes Kepler published a book which included his first two “Laws of Planetary Motion”. These laws explain why the apparent size of the sun changed, and why the speed of a planet changes as it orbits the sun. This is because the orbits of the planets were “elliptical” and not circular.
VIII. The Moon A. The moon is a natural satellite of Earth 1. Luna - Latin word for the moon 2. Diana - Roman goddess of the moon
B. Physical Properties of the Moon 1. Size 2. a. Diameter: 2160 miles 3. b. compared to Earth– diameter of: moon/earth=2160/8000 miles= 1/4 2. Gravity a. 1/6 the gravity of Earth b. Smaller- less mass 3. Atmosphere a. virtually none b. gravity too weak- gases escape out into space 4. Temperatures a. 240 degrees Fahrenheit on the lighted side b. -240 degrees Fahrenheit on the dark side c. These large temperature extremes or differences exist because the moon does not have an atmosphere to transfer heat
C. Lunar Topography- surface features of the moon
1. Craters- bowl-shaped depressions formed primarily as a result of impact of meteors. 2. 3. a. Examples: Copernicus, Kepler, Tycho, Ptolemaeus b. There are many more craters on the moon than on Earth because the moon does not have an atmosphere to 1. burn up incoming meteors and 2. no cause erosion to wear them away 2. Maria- appear as the “dark areas” on the moon’s surface; once thought to be “seas”. Extensive, circular, flat/smooth areas, or plains resulted from lava flows during a much earlier period of the moon’s evolution. a. examples: Mare Tranquillitatis- Sea of Tranquility, Mare Nubium - Sea of Clouds, Oceanus Parcellarum - Ocean of Storms, Mare Serenitatis - Sea of Serenity, Mare Imbriam – Sea of Showers, Mare Crisium - Sea of Tears
3. Rays- appear as “bright streaks” that radiate from certain craters. Consist of shattered debris that was splashed out by the impact of meteors that formed the craters 4. Highlands- appear as the “light areas” on the moon’s surface. Consist of craters and mountains Examples of lunar mountains: Alps, Jura, Carpathian, Apennine, Caucasus, Pryrenes D. The Moon’s Revolution 1. Period of Revolution 2. a. 1 month or 29. 5 days 2. The moon revolves around Earth in an elliptical orbit, and Earth is at one foci.
3. This causes the moon’s apparent diameter/size to change in a cyclic manner. E. Phases by the moon 1. Caused by the moon’s revolution around Earth 2. Our Earth view of the changing illuminated part of the moon’s surface that faces Earth 3. The moon orbiting Earth as viewed from space:
Phases of the Moon The general locations and orientations for the phases of the moon. (7) Third Quarter (6) Waning (8) Waning Gibbous Crescent Sunlight Earth (1) New Moon (5) (2) Waxing Full Moon (4) Waxing Crescent 31 Earth spins on its axis in the same direction as the moon’s orbit. (3) First Quarter Gibbous
Perspective & The Moon’s Face How much of the moon’s face does the person see? Sunligh t NEW MOON Wherever the person looks all they see is shadowed moon. 31 (1) New Moon Earth
Perspective & The Moon’s Face How much of the moon’s face does the person see? Sunligh t WAXING CRESCENT When you look up you see only a small crescent brightly lit. (Right Side) 31 Earth (2) Waxing Crescent
Perspective & The Moon’s Face How much of the moon’s face does the person see? Sunligh t Earth Sunligh t FIRST QUARTER When you look up you see one half of the front face of the Moon brightly lit. (Right side) 31 (3) First Quarter
Perspective & The Moon’s Face How much of the moon’s face does the person see? Sunligh t WAXING GIBBOUS When you look up you see only a small crescent, darkly shadowed, on the left. 31 Earth (4) Waxing Gibbous
Perspective & The Moon’s Face How much of the moon’s face does the person see? Sunligh t FULL MOON When you look up you see the entire face of the Moon brightly lit. 31 Earth (5) Full Moon
Perspective & The Moon’s Face How much of the moon’s face does the person see? Sunligh t WANING GIBBOUS When you look up you see only a small crescent, darkly shadowed, on the right. 31 (6) Waning Gibbous Earth
Perspective & The Moon’s Face (7) Third Quarter How much of the moon’s face does the person see? Sunligh t THIRD QUARTER When you look up you see one half of the front face of the Moon brightly lit. (Left side) 31 Earth
Perspective & The Moon’s Face How much of the moon’s face does the person see? (8) Waning Crescent Sunligh t WANING CRESCENT When you look up you see only a small crescent brightly lit. (Left Side) 31 Earth
Phases of the Moon The general locations and orientations for the phases of the moon. (7) Third Quarter (6) Waning (8) Waning Gibbous Crescent Sunlight Earth (1) New Moon (5) (2) Waxing Full Moon (4) Waxing Crescent 31 Earth spins on its axis in the same direction as the moon’s orbit. (3) First Quarter Gibbous
These 2 photos were taken with the same camera with the Same settings. Why are they different sizes? Moon’s orbit is elliptical – therefore sometimes it is closer while at other times it is further away.
What phase is the moon? Full Moon What time of day will this moon phase be high in the sky? (meridan) Midnight What time will this moon phase set? sunrise What time will this moon rise? sunset
b. Phases of the moon as viewed from Earth c. (1) Wanning- the decreasing of the moon’s visible illuminated surface; from full moon to new moon (2) Waxing- the increasing of the moon’s visible illuminated surface; from new moon to full moon.
This vintage 60 -kopek stamp celebrates a dramatic achievement. On the 7 th of October, 1959, the Soviet "Luna 3" successfully photographed the far side of the moon giving denizens of planet Earth their first ever view of this hidden hemisphere. Lacking the digital image technology familiar now, Luna 3 took the pictures on 35 mm film which was automatically developed on board. The pictures were then scanned and the signal transmitted to Earth days later in what was perhaps also the first interplanetary fax. In all, seventeen pictures were received providing enough coverage and resolution to construct a far side map and identify a few major features. Depicted on the stamp are regions dubbed the Sea of Moscow, the Soviet Mountains, the Bay of Astronauts, and the Sea of Dreams.
Have you ever seen a halo around the Moon? This fairly common sight occurs when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Moon Halo. A similar Sun Halo may be visible during the day. The picture was taken in Lansdowne, Pennsylvania, USA. Exactly how ice-crystals form in clouds remains under investigation.
F. The Near and Far Side of the Moon 1. Near side- the side of the moon that always faces Earth. It is nearly half highlands and half maria. 2. Far side- the side of the moon that never faces Earth. It is mostly highlands/craters. 3. The same side of the moon (the near side) always faces Earth because: the moon’s period of rotation equals its period of revolution.
Phases of the Moon The general locations and orientations for the phases of the moon. Sunlight 31 Earth spins on its axis in the same direction as the moon’s orbit.
Lunar Eclipse Annular Solar Total Solar Eclipse
Totality- a total eclipse of the sun H. Tides 1. Tides are the periodic rising and falling of the oceans a. Caused by the Moon’s gravity b. Affected by Earth’s rotation 2. The period from high tide to high tide is normally about 12 hours and 25 minutes. It is a cyclic change.
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