Volcanoes and Igneous Activity Earth - Chapter 4

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Introduction to Astronomy
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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.
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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
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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)
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(No Transcript)
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Retrograde Motion
Animation
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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/
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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

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Planet revolution
1st 2nd Law Animations
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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
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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/
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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
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Gravitys influence on orbits
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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
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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
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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
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Precession
Animation
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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
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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

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Phases of the Moon
What is a blue moon?
YouTube Song
Phases of the Moon
Moon Phases Animation
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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
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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.

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Solar Eclipse
What phase is the moon in during a solar
eclipse? and what time of day?
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Solar Eclipse
Eclipses For 2013
Solar eclipse
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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.

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Lunar Eclipse
Lunar eclipse
What phase is the moon in during a lunar
eclipse? and what time of day?
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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.

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Origin of the moon
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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
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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!