Ch 19 Earth, Moon, Sun Sec 1

1
Ch 19 Earth, Moon, Sun Sec 1

• The Earth moves through space 2 ways
• Rotation spinning on its axis. Causes day and
  night, takes 24 hours.
• Revolution the movement of the Earth around the
  sun, takes 365 ¼ days
• We have 4 different seasons due to the tilt of
  the Earths axis ( 23 ½ º ) and its revolution.
• Northern hemisphere seasons include.
• Dec 21 Winter Solstice March 21 Spring
  Equinox
• June 21 Summer Solstice Sept 21 Fall Equinox
• Summer solstice is the longest amount of daylight
  all year long due to the earths tilt.
• Winter solstice is the shortest amount of
  daylight all year long due to the earths tilt.
• Equinoxes have equal amounts of day and night (12
  hr)

2
Gravity and Motion Sec 19-2

• Gravity is a force of attraction between objects.
  Newtons laws of motion and gravity state that
  every object in the universe attracts each other
• Gravity strength depends on distance and mass.
• Weight is the measure of gravity
• Earth weight 120 lbs Moon weight 20 lbs
• Inertia is when an object resists change in
  motion. Newtons first law of motion states
• An object at rest will remain at rest and an
  object in motion will remain in motion unless
  acted upon by a force.
• Therefore the moon stays in orbit around the
  Earth because of the inertia of the moon and the
  gravity of the Earth.

3
Phases, Eclipses, and Tides 19-3

• The motion of the moon, the sun and the earth all
  make the phases, eclipses, and tides.
• Phases of the moon depend on how much of the
  sunlit side of the moon we see.
• New Moon cant see the moon dark side
• Waxing Crescent only a banana shape
• First Quarter looks like half the moon
• Waxing Gibbous - see most of it, football shape
• Full Moon see one whole side of the moon
• Waning Gibbous - see most of it, football shape
• Third Quarter - looks like half the moon
• Waning Crescent - only a banana shape

4

• An eclipse is when the moons shadow hits the
  earth or the earths shadow hits the moon.
• Pages 674 675 show both eclipses.
• During a solar eclipse the sun or part of it is
  covered by the moon.
• During a lunar eclipse the moon or part of it is
  covered by the earths shadow.
• If either is fully covered it is called a total
  eclipse, because they are in the umbra shadow
  which is the darker area.
• If they are only slightly covered partial
  eclipse, because they are in the penumbra shadow
  which is not as dark.
• Tides are the rise and fall of the earths oceans
  due to the moons gravity. Spring tides are
  higher then usual tides and neap are lower then
  normal.

5
Earths Moon Sec 19-4

• Telescope invented by Galileo Galilei, an
  Italian scientist. Helpful in studying the moon.
• Features on the moon include
• Marias dark flat areas (looked like seas)
• Craters round pits from meteoroid collisions
• -more on the dark side-facing away from earth
• Highlands light colored areas mountains
• Rilles valleys in the moon
• Diameter 3500 km
• Distance 384,000 km from earth
• Temperature 130C daytime and -180C night
• No liquid water, no atmospheric gases
• Origin may be from an object striking the early
  earth to make a chunk of material that became the
  moon, or it formed the same way the earth did in
  a nebula

6
Space Travel Sec 19-5

• First space travels were done via a rocket.
• Rocket device that expels gas in one direction
  to move in the opposite direction. (Thrust)
• One of Newtons laws for every action there is
  an opposite and equal reaction.
• Escape velocity is the speed needed to break away
  from the earths gravitational pull.
• Orbital velocity is the speed needed to establish
  an orbit around the earth.
• Multistage Rockets smaller rockets are pieced
  together to form a larger one, the advantage is
  that as the rocket rises pieces can fall off
  reducing the weight of the overall rocket.

7

• The Space Race was the early exploration of space
  between the US and Russia in the 1950s and up
  through the cold war.
• Sputnik I was the first artificial satellite in
  space launched by Russia in 1957. The US
  launched its first satellite called Explorer 1 in
  1958.
• Yuri Gargarin was the first human in space in
  1961 he was russian. The Us later had Alan
  Shepard as our first man in space.
• John Glenn became the first human to orbit the
  earth in 1962 and the oldest human in 1998 at age
  77
• July 20th 1969 - Apollo 11 land on the moon
• Neil Armstrong was the 1st person on the moon
• Buzz Aldrin was the 2nd person on the moon
• Michael Collins flew them there on the Columbia,
  and the lander was called the Eagle.

8

• Todays space exploration is done through the
  space shuttle here in the US. Shuttles take
  satellites into orbit, repairing damaged
  satellites, and carrying humans to and from the
  space station where long-term observations and
  experiments can be carried out in the environment
  of space.
• Space Probes gather data about distant parts of
  the solar system where humans cant go
• Mars we have been exploring this planet with
  rovers as well as probes. Rovers are remote
  control vehicles that can move around on the
  surface.
• Some current probes include the cassini probe at
  the planet Saturn, New Horizons on its way to
  Pluto, Hubble Telescope orbiting the Earth,
  Voyager I and Voyager II are both still going for
  over 20 years.