Chapter 1 Earth, Moon, and Sun

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Chapter 1Earth, Moon, and Sun
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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

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• 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

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• 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

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• 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

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• 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)

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• 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

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• 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

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• 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

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• 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

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Section 1.2Phases, 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.

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• 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

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• 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.

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• 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!)

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• 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

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• 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

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• 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

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• 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

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• 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

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• 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

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• 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

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Section 1.3Rockets 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

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• 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

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• 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!

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• 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!)

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• 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

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• 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?

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Section 1.4Earths 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

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• 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

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• 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

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• 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

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• 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

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• 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