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Volcanoes and Igneous Activity Earth - Chapter 4

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Title: Volcanoes and Igneous Activity Earth - Chapter 4 Author: Stan & Cindy Hatfield Last modified by: Home Created Date: 12/18/2000 12:31:17 AM – PowerPoint PPT presentation

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Title: Volcanoes and Igneous Activity Earth - Chapter 4


1
Introduction to Astronomy
2
What is astronomy?
  • Astronomy is the science that studies the
    universe. It includes the observation and
    interpretation of planets, stars, and other
    bodies in space.

http//science.howstuffworks.com/telescope.htm
Image credit NASA / Apollo 8 crewmember Bill
Anders.
3
Early astronomy
  • (Those Ancient Greeks! Yes they were very smart.
    Observed the heavens, applied philosophy)
  • Aristotle popularized the
  • Geocentric model of the universe
  • Geo __________ centr __________
  • Earth is the center of the universe the sun and
    other plants revolve around it

Aristotle (the guy in Carolina blue), as painted
by Raphael
4
Why do the planets sometimes move backwards?
  • Early astronomers observed
  • planets move eastward against the background of
    stars.
  • Sometimes the planets seemed to stop, reverse
    direction, and then later carry on eastward.
  • This apparent westward (backward) motion of the
    planets is called retrograde motion
  • Important! because it made them question the
    geocentric model

(really puzzling)
5
(No Transcript)
6
Retrograde Motion
Animation
7
Birth of modern astronomy
  • Nicolaus Copernicus
  • Earth is a planet
  • proposed the
  • Heliocentric model of the solar system
  • Helio __________ centr __________
  • Sun is the center of the solar system, planets
    revolve around it (including Earth)
  • better explained retrograde motion

Nicolaus Copernicus
http//www.universetoday.com/33113/heliocentric-mo
del/
8
Keplers Laws of Planetary Motion
  • Kepler used Brahes observations to develop 3
    laws to explain the movement of the planets
  • 1st Law Planets move in elliptical (oval) orbits
    around the sun
  • 2nd Law Planets move faster when they are closer
    to the sun

9
Planet revolution
1st 2nd Law Animations
10
Keplers Laws of Planetary Motion
  • Kepler used Brahes observations to develop 3
    laws to explain the movement of the planets
  • 1st Law Planets move in elliptical (oval).orbits
    around the sun
  • 2nd Law Planets move faster when they are closer
    to the sun.
  • 3rd Law The further the planet is from the sun,
    the longer its orbital period (p2a3)
  • orbital period is the time (in Earth years) it
    takes a planet to go once around the sun.

3rd Law Animation
11
Galileos telescope
  • Galileo improved on the new invention the
    telescope
  • Amazing discoveries in great detail
  • Detailed records of the heavens

http//news.nationalgeographic.com/news/2009/08/ph
otogalleries/galileos-telescope-pictures-anniversa
ry/
12
Sir Isaac Newton one heavy dude
  • Developed a formula to explain gravity, now
    called the law of universal gravitation
  • All objects with mass have a gravitational pull
  • The greater the mass of an object, the greater is
    its pull on other objects
  • The pull decreases with distance
  • Meaning for the planets?
  • Tennis ball demo

Gravity
13
Gravitys influence on orbits
14
Motions of Earth
  • Rotation
  • The turning, or spinning, of a body on its axis
  • Responsible for our days and nights (why?)
  • One complete earth rotation (one noon to the
    next) is about _____ hours

http//www.physicalgeography.net/fundamentals/6h.h
tml
15
Motions of Earth
  • Revolution
  • The motion of a body, such as a planet or moon,
    along a path around some point in space (in this
    case, the sun)
  • One complete earth revolution is about _____ days
  • Perihelion is the time in Jan when Earth is
    closest to the sun aphelion is the time in July
    when Earth is farthest from the sun
  • Volunteer ?

http//science-class.net/Notes/Notes_Seasons_7th.h
tm
16
Motions of Earth
  • Precession
  • The change in the direction in which the axis of
    the Earth points
  • Earths wobble
  • One complete cycle occurs about every _____
    years
  • In 13,000 years (half-way), Polaris will no
    longer be our North Star. instead it will be
    the star Vega (and summer will be winter)

Volunteer?
http//www.dreamstime.com/royalty-free-stock-image
s-spinning-top-toy-image15214709
17
Precession
Animation
18
Why do we have seasons?
  • Earths tilt on its axis, along with its
    revolution around the sun causes the seasons!
  • As Earth moves around the sun, the tilt changes
    the angle of light received from the sun
  • Light hitting at direct angle summer
  • Light hitting at indirect angle winter

Earths Seasons
http//education.arm.gov/teacher-tools/lessons/rea
son
19
Phases of the moon
  • The moon revolves around Earth
  • One complete revolution is about _____ days
  • The moon changes shape (phase) because of the
    changing amount of sunlight reflected off the
    moon
  • These changes occur monthly

20
Phases of the Moon
What is a blue moon?
YouTube Song
Phases of the Moon
Moon Phases Animation
21
Motions of the moon
  • The moons period of rotation on its axis and its
    revolution around Earth are the same (about a
    month)
  • SO we always see the same side of the moon
  • volunteer?

Why We See The Same Side of The Moon
22
Eclipses
  • Normally the moon orbits about 5 degrees off the
    earth-sun orbital plane
  • At special times of the year, the earth, moon,
    and sun line up
  • Solar eclipse when the moon is directly between
    Earth and the sun, casting a shadow on part of
    Earth.

23
Solar Eclipse
What phase is the moon in during a solar
eclipse? and what time of day?
24
Solar Eclipse
Eclipses For 2013
Solar eclipse
25
Eclipses
  • Normally the moon orbits about 5 degrees off the
    earth-sun orbital plane
  • At special times of the year, the earth, moon,
    and sun line up
  • Solar eclipse when the moon is directly between
    Earth and the sun, casting a shadow on part of
    Earth.
  • Lunar eclipse when Earth is directly between the
    moon and the sun, casting a shadow on the moon.

26
Lunar Eclipse
Lunar eclipse
What phase is the moon in during a lunar
eclipse? and what time of day?
27
Origin of the moon
  • Most widely accepted theory
  • When the solar system was forming, a body the
    size of Mars hit Earth. The resulting debris was
    thrown into space, began orbiting around Earth,
    and eventually united to form the moon.

28
Origin of the moon
29
Why is the moon so important?
  • The moon calms Earths tilt controls our tides,
    and so much more!
  • While watching the movie, describe at least 10
    ways our Earth would be different if we had no
    moon (page 17 in your notebook)

The Day the Moon Was Gone (Amazon)
Pt.1 start _at_ 43.24
30
Your summary
  • Discuss with your table partner about what you
    will write in your summary box
  • Should be 1-3 sentences giving the major points
    of the Intro Astronomy notes
  • then write your summary!
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