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Chapter 1 Earth, Moon, and Sun

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Earth, Moon, and Sun Days & Years The ancient egyptians were among the first to study the stars. They noticed the bright star Sirius in the morning sky shortly before ... – PowerPoint PPT presentation

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Title: Chapter 1 Earth, Moon, and Sun


1
Chapter 1 Earth, Moon, and Sun
2
Section 1.1 Earth in Space
  • Days Years
  • The ancient egyptians were among the first to
    study the stars. They noticed the bright star
    Sirius in the morning sky shortly before seasonal
    floods.
  • astronomy- the study of the moon, stars, other
    objects in space
  • It was thought that the Earth stood still that
    the sun and moon were moving around the Earth

3
  • Rotation
  • axis- the imaginary line that passes through
    Earths center the North and South Poles
  • the northern axis points to Polaris (North Star)
  • rotation- the Earth spinning on its axis
  • Earths rotation on its axis causes the day
    night
  • as the Earth rotates eastward, the sun appears to
    move westward across the sky
  • it takes 24 hours for the Earth to complete one
    full rotation on its axis

4
  • Revolution
  • revolution- the movement of an object around
    another object
  • it takes one year (365 days) for the Earth to
    complete one full revolution around the sun
  • orbit- the Earths path as it revolves around the
    sun Earths orbit is an oval shape

5
  • Calendars
  • Egyptians counted the days between the first
    appearance of the star Sirius (365 days) creating
    one of the first calendars
  • Earths actual orbit is 365 1/4 days creating
    every 4 years a leap year which has 366 days
    (February gains a day giving it 29)
  • early cultures used moon cycles as a kind of
    calendar with the time between one full moon and
    the next being about 29 1/2 days called moonths
  • Egyptians created 12 months with 30 days each
    with an extra 5 days that were just there
  • The Romans borrowed the Egyptian calendar, made
    some changes it became the calendar we use today

6
  • Seasons on Earth
  • there are 4 distinct seasons on Earthwinter,
    spring, summer, autumn (fall)
  • at the equator, sunlight hits the Earth directly
    (constant warm weather) closer to the poles,
    sunlight hits the Earth on an angle spreading it
    out over a greater area (cooler weather the
    further from the equator you go, until it turns
    very cold at the poles)

7
  • Earths Tilted Axis
  • it the Earths axis was straight up down, the
    weather would remain fairly constant throughout
    the year
  • Earth has seasons because its axis is tilted as
    it moves around the sun
  • the Earths tilt is 23.5 degrees from vertical
    as the Earth moves in its orbit it is pointed
    toward the sun for part of the year away from
    the sun for the other part of the year
  • when the north end of the Earths axis is pointed
    toward the sun, the Northern Hemisphere has
    summer when the axis is pointing away, the
    Northern Hemisphere is having winter
  • seasons are not affected by the Earths distance
    from the sun

8
  • Earth in June
  • the north end of the Earths axis is pointing
    directly toward the sun with the noon sun
    directly overhead at 23.5 degrees north latitude
  • latitude- a measurement of distance from the
    equator expressed in degrees north or south (the
    equator latitude is 0 degrees the North Pole 90
    degrees North)
  • the hemisphere tilted toward the sun has more
    hours of daylight heating the Earths surface
    more than any other time of the year (summer)
  • summer in the Northern Hemisphere means that it
    is winter in the Southern Hemisphere visa versa

9
  • Earth in December
  • the south end of the Earths axis is pointing
    directly toward the sun with the noon sun
    directly overhead at 23.5 degrees south latitude
  • the Southern Hemisphere is having summer
    Northern Hemisphere is having winter
  • Both June December
  • solstice- 2 days each year, the noon sun points
    directly to 23.5 degrees south or north the 2
    longest days of the year
  • 23.5 degrees south is the winter solstice 23.5
    degrees north is the summer solstice in the
    Northern Hemisphere

10
  • Earth in March September
  • equinox- occurs only 2 days out of the year
    halfway between the each solstice where neither
    hemisphere is tilted toward or away from the sun
    means equal night where the amount of
    daylight night are the same
  • vernal equinox- (spring equinox) occurs around
    March 21 marks the beginning of spring in the
    Northern Hemisphere
  • autumnal equinox- occurs around September 23
    marks the beginning of fall in the
    Northern Hemisphere
  • seasonal changes affect living things in the
    fall, the plant life dies off, birds fly to
    warmer climates, some animals become dormant
    entering hibernation in the spring plants begin
    to grow, the birds return, animals awaken from
    hibernation

11
Section 1.2 Phases, Eclipses, Tides
  • the moon is Earths closest neighbor out in space
    at 384,400 kilometers out in space or 30 Earths
    lined up in a row
  • the moon revolves around the Earth as the Earth
    revolves around the sun
  • The positions of the moon, Earth, the sun cause
    the phases of the moon, eclipses, and tides.

12
  • Motions of the Moon
  • as the moon revolves around the Earth it rotates
    on its own axis its orbit similar to Earths as
    a flat oval
  • the moon takes about 27.3 days to orbit around
    the Earth it also takes 27.3 days to complete
    one revolution on its own axis causing a moon
    day a moon year to be the same length of
    time
  • the near side of the moon always faces Earth
    the far side of the moon always faces away from
    Earth is never seen

13
  • Phases of the Moon
  • the moon does not produce its own light, instead
    it reflects the light from the sun
  • phases- the different shapes of the moon when
    seen from Earth
  • the moon has 8 phases and goes through the whole
    set once a month
  • What Causes Phases?
  • phases are caused by changes in the relative
    position of the moon, Earth, sun
  • The phase of the moon you see depends on how much
    of the sunlit side of the moon faces Earth.

14
  • The Cycles of the Phases
  • at new moon, the lit side of moon is not facing
    the Earth, so from Earth no moon is seen
  • as the moon revolves around the Earth it appears
    to grow, from the right side to the left, with
    more more of it becoming visible until it if
    fully lit (full moon)
  • from one full moon to the next it takes about
    29.5 days
  • The 8 phases of the moon in order are New Moon,
    Waxing Crescent, First Quarter, Waxing Gibbous,
    Full Moon, Waning Gibbous, Third Quarter, Waning
    Crescent
  • see page 26 in book for pictures details (on
    quiz test!)

15
  • Eclipses
  • the moon rarely goes directly between the Earth
    the sun because its orbit around the Earth is
    slightly tilted with respect to Earths orbit
    around the sun
  • When the moons shadow hits Earth or Earths
    shadow hits the moon, an eclipse occurs.
  • eclipse- occurs when an object in space comes
    between the sun an a third object, and casts a
    shadow on that object
  • there are 2 types of eclipses solar (sun)
    eclipse lunar (moon) eclipse

16
  • Solar Eclipse
  • solar eclipse- occurs when the moon passes
    between Earth the sun, blocking the sunlight
    from reaching Earth
  • Total Solar Eclipse
  • umbra- the darkest park of the moons shadow is
    cone-shaped
  • the cone of the umbra is very narrow on the face
    of the Earth so that only people in the umbra
    experience a total solar eclipse
  • during a total solar eclipse, the sky is dark,
    you can see the stars, the solar cornea (the
    faint outer atmosphere of the sun)
  • Partial Solar Eclipse
  • penumbra- a lighter shadow cast by the moon is
    the larger part of the overall shadow
  • in the penumbra, people only see a partial
    eclipse since part of the sun is still visible,
    it is not safe to look directly at the eclipse

17
  • Lunar Eclipse
  • lunar eclipse- occurs at a full moon when Earth
    is directly between the moon and the sun
  • the Earth blocks the suns light from reaching
    the moon making the moon look dark from Earth
  • Total Lunar Eclipse
  • when the moon is in the Earths umbra, there is a
    total lunar eclipse
  • a lunar eclipse can be seen anywhere on Earth
    that the moon is visible
  • Partial Lunar Eclipse
  • Earth, the moon, and the sun are not in a line
    creating a partial lunar eclipse
  • the moon passes partly into the umbra of the
    Earths shadow

18
  • Tides
  • tides- the rise fall of water, about every 12.5
    hours
  • What Causes Tides?
  • gravity- the attractive force between two
    objects its magnitude depends on their masses
    and the distance between them
  • Tides occur mainly because the differences in how
    much the moon pulls on different parts of the
    Earth
  • as the Earth rotates, the moon pulls water toward
    the point on Earth closest to the moon the 2
    tides (on opposite sides of the globe) occur
    because the difference in the force of gravity
    from one place to another
  • High Tides
  • water from one place is pulled more strongly
    toward the moon due to gravity than another, but
    due to the Earths rotation, that location
    changes throughout the day

19
  • The Tide Cycle
  • at any one time there are 2 places with high
    tides and 2 places with low tides n Earth
  • as the Earth rotates the high tide stays on the
    side facing the moon the second high hide is on
    the opposite side of the Earth
  • the tides rotate in a 25 hour cycle

20
  • Spring Neap Tides
  • the suns gravity also pulls on the Earth once
    a month the sun, Earth, moon are in a line so
    that there gravities pull in the same direction
  • spring tide- the combined forces of the sun
    moons gravity produce a tide with the greatest
    difference between high low tide
  • spring tides twice a month , one at full moon
    one at new moon
  • neap tide- when the sun Earth are at right
    angles with each other, as well as the angle
    between the Earth the moon is a right angle
  • neap tides happen 2 times a month, one at first
    quarter moon one at last quarter moon

21
  • Local Tide Effects
  • the shape of the coastline effects whether or not
    a place has regular tides
  • on the seashore there is an intertidal zone, that
    is under water at high tide but is dry land
    during low tide
  • many animals sea creatures live in the
    intertidal zone like sea stars, barnacles, clams,
    oysters

22
Section 1.3 Rockets Satellites
  • How Rockets Work Blast off!!!
  • A rocket moves forward when gases expelled from
    the rear of the rocket push it in the opposite
    direction.
  • Newtons 3rd law of Physics For every action
    there is an opposite and equal reaction.
  • the fuel inside the rocket burns creating hot gas
    which is then forced out of a narrow hole in the
    back of the rocket propelling it upward

23
  • Multistage Rockets
  • early rockets, built in China around year 1000,
    used gun-powder for its fuel, but it burned too
    quickly was explosive
  • American scientist Robert H. Goddard experimented
    with liquid fuels finding that they gave off a
    slow continuous burn
  • in 1903, a Russian scientist founded a multistage
    rocket with fuel in each section as the fuel is
    used up, the empty section falls off the next
    stage is ignited
  • this style of rocket made possible sending man to
    the moon in the 1960s
  • Moon Landing

24
  • Artificial Satellites
  • satellite- any natural or artificial object that
    revolves around an object in space
  • October 4, 1957, the Soviet Union (Russia)
    launched Sputnik 1, the worlds 1st artificial
    satellite which revolved around Earth every 96
    minutes
  • January 1958, the USA launched Explorer 1
  • April 12, 1961, Yuri Gagarin, a Russian
    cosmonaut, orbited Earth became the 1st person
    in space
  • since 1957, thousands of artificial satellites
    space stations have been launched they are used
    for communication, navigation, collecting weather
    data, research
  • Good Job Yuri!

25
  • Satellites
  • satellites give off signals that can be picked up
    by small receivers on Earth for many different
    purposes
  • some satellites are in geosynchronous orbits-
    they revolve around the Earth at the same rate
    that the Earth rotates
  • these satellites are used to relay television
    signals to map weather patterns
  • beep beep bloop bleep
    (Dont ask use what
    the weather
    will be, even we
    dont know!)

26
  • Space Stations
  • is a large satellite in which people can live for
    long periods of time
  • 1st station was the Russian Salyut in 1971
  • in 1973 the USA launched Skylab which carried out
    telescopes, medical, geological, astronomical
    experiments
  • the Mir, name meaning peace, (Russian) space
    station was launched in 1986
  • astronauts for 16 different countries cooperated
    to build the International Space Station

27
  • Space Shuttles
  • the Saturn V rockets that took men to the moon in
    the 1960s 70s were expensive couldnt be
    reused
  • in the late 1970s, NASA (National Aeronautics
    Space Administration) developed reusable space
    shuttles that could go back forth between Earth
    space with the first being launched in 1981
  • are the main way to get men equipment to space
    are only designed to orbit Earth
  • Did I remember to turn off the lights?

28
Section 1.4 Earths Moon
  • there is no air or liquid water on the moon
  • temperatures range from 100ºC to -170ºC
  • the moons gravity is 1/6 of the Earths
  • The Structure the Origin of the Moon
  • moon has the diameter of 3,476 km (little less
    than the distance across the US) which is about
    1/4 of the Earths diameter
  • has a very dense core, but the outer layers are
    much less dense
  • theory of the moons origin is the collision
    theory about 4.5 million years ago, an object
    collided with a molten Earth taking parts of the
    object the molten Earth into Earths orbit

29
  • Looking at the Moon From Earth
  • ancient Greeks thought the moon was smooth
  • in 1609, Galileo made his own telescope- putting
    2 lenses in a wooden tube making distant objects
    appear closer when viewed
  • features on the moons surface include craters,
    highlands, marias
  • Galileo saw that much of the moon was covered in
    craters- round pits were created meteoroid
    impacts not volcanoes
  • the higher portions of the moons surface cast
    dark shadows
  • Galileo saw maria- large, dark, flat areas on the
    moon which is the Latin word for seas because
    he thought that they were oceans marias were
    formed by areas flooded by molten material
    billions of years ago
  • the same side of the moon always faces the Earth

30
  • Missions to the Moon
  • president John F. Kennedy launched the space
    program in 1961
  • Exploring the Moon
  • between 1964-1972 the US Russia launched dozens
    of rockets to the moon because no one knew what
    the surface of the moon was like
  • when the Surveyor spacecraft landed it showed
    that the surface was solid
  • lunar orbiters took pictures to find a flat
    surface to land a rocket on

31
  • The Moon Landing
  • July 20, 1969 the 3 astronauts of Apollo 11
    orbited the moon
  • Neil Armstrong Buzz Aldrin got into the Lunar
    Module Eagle and descending onto the moon in an
    area called the Sea of Tranquility The Eagle
    has landed!
  • That is one small step for man, one giant leap
    for mankind. - Neil Armstrong

32
  • On the Surface of the Moon
  • astronauts took samples of the moons soil to
    bring back to Earth to study 382 kg (840.4
    pounds) of samples!
  • Moon Rock Moonquakes
  • much of what scientists have learned about the
    moon came from detailed study of the moon rocks
    gathered by astronauts
  • all of the samples were made of a molten material
    showing that at one time the moons surface was
    very hot
  • a seismometer was used to detect earthquakes on
    the moon it detected weak moonquakes
  • astronauts left a piece of equipment on the moon
    used to monitor the flow of heat energy from the
    moons interior shows that the moon has almost
    completely cooled since its formation

33
  • Photographs of the Moon
  • pictures show that the far (dark) side of the
    moon is rougher than the near side has very few
    maria
  • the American Clementine spacecraft was launched
    in 1994 took filtered pictures of the moon
    showing what types of minerals were present
  • American Lunar Prospector spacecraft mapped the
    entire moon surface from a height of 100 km
    finding evidence of ice frozen in the soil near
    the moons poles
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