Astronomy

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Astronomy

• Chapter 22-25

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Warm Up Sept 7

• http//www.youtube.com/watch?vjRXQsQKGqIU
  creepy twinkle
• http//www.youtube.com/watch?vyCjJyiqpAuU cute
  twinkle
• Compare and contrast each version using a Venn
  Diagram
• Which one do you like more? Why?
• Which one best describes human curiosity towards
  outer space? WHY?

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Time Line

• Create a time to include each of the following
  people (include their discovery).
• Aristotle
• Eratosthenes
• Hipparchus
• Aristarchus
• Claudius Ptolemy
• Nicolaus Copernicus
• Tycho Brahe
• Johannes Kepler
• Galileo Galilei
• Sir Isaac Newton

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What is the Golden Age of Astronomy?

• The shift away from the idea of a Geocentric
  Universe.

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What is Modern Astronomy?

• Nicolaus Copernicus (1473-1543)
• Earth is just a planet
• Universe is sun centered
• Mercury, Venus, Earth, Mars, Jupiter, and Saturn
• Circular orbits around sun
• Tycho Brahe (1546-1601)
• Used pointers to estimate distance
• Pointers think big protractor
• Mentor Kepler

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Who was Johannes Kepler (1571-1630)?

• Brahes observations of Mars
• Noticed that the orbit was not Circular
• Kepler used his QAs to form 3 Laws of Planetary
  Motion
• 1st Law
• Ellipse (Oval)
• 2 foci
• Star

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Laws of Planetary Motion

• 2nd Law
• Sun sweeps over equal areas in the same amount of
  time.
• Close to sun faster
• Away from sun slower
• 3rd Law
• Orbital Period (time) of planet is proportional
  to distance from the sun (P2d3), expressed in AU
  units (1AU 1.5Million Km)

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Who is Galileo Galilei?(1564-1642)

• Telescope
• Behavior of moving objects
• Observation supported Copernicuss view of the
  universe
• Moons of Jupiter (4) Earth is not the center of
  all universal motion
• Planets are circular disc must be Earth-like
• Venus has phases like the moon orbits light
  source (sun)
• Moons surface not smooth validated others who
  named areas based on features (Sea of
  Tranquility)
• Sun has dark regions tracked movement est.
  rotation period of sun under 1 month

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What is the Law of Universal Gravitation?

• Sir Isaac Newton (1642-1727)
• ? Kepler some force pushes the planets along
  their orbits
• ? Galileo no force is required to keep an object
  in motion
• Inertia
• Every body attracts directly proportional to mass
  inversely proportion to distance2 b/w the
  bodies
• Revised Keplers 3rd law (mass)

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What are Earth Motions?

• Rotation
• Spinning on axis (day/night)
• Solar day
• noon to noon
• Sidereal day
• Based on a distant star
• 23hr 56 min
• Distance to the stars change by tiny increments
• Sun changes by 1 a day

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Earth Motions Cont.

• Revolution
• Moving around another body
• Distance of the sun to the Earth _at_150 million km
• Elliptical Orbit
• Perihelion _at_ January 3
• 147 million km
• Aphelion _at_July 4
• 152 million km

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Earth Motions Cont.

• Precession
• Change in tilt of axis
• 23.5 always the same
• Slow _at_ 26 000 years
• Changes North Star
• Polaris to Vega
• Nutation
• Wobbling around the axis
• Caused but the moons pull
• Slight seasonal change.
• Remember Galaxies on the move!

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What are Axis Seasons?
Why do different season exist?
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Axis Seasons cont.
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Moon (Satellite) Motions

• Revolution 1month (29 ½ days)
• Ave. distance 384 401Km (6)
• Perigee closest to Earth
• Apogee farthest
• Phases of the Moon
• Waxing
• Waning

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How do Eclipses work?
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What is Barycenter?

• The center of mass is the balance point between
  two orbiting bodies, like a seesaw.

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The Sun

• Average Star
• Some Stats
• Diameter 109 Earth diameters
• Volume 1.25 million times Earths
• Mass 332,000 times Earths
• Density 1/4th of solid Earth

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Sun Structure

• Structure
• the Solar Interior
• Photosphere
• 2 Atmospheric Layers
• Chromosphere
• Prominences
• Corona
• Solar Winds

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Solar Flares Sunspots

• Solar Flares
• Auroras
• Sunspots
• 11 year cycle
• Last days to weeks

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The Solar interior

• Nuclear Fusion
• Emc2
• It takes very little hydrogen to make a lot of
  energy.
• Most of the hydrogen is not converted to energy.

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Other Stuff

• Scientific Methods Quiz Redo
• A problem is a question to be answered!!!!!
• Answer the QUESTION!!!!!!!!!!!!!!!!
• Do not for get the problem/hypothesis
  relationship!!!!!
• Example Problem
• Does the presence of grain-eaters in the desert
  environment cause a decrease in wildflower
  diversity?
• Example Hypothesis
• If grain-eaters are eliminated from the
  environment by a fence, then the wildflower
  diversity will increase by 20.
• Independent Variable
• Dependent Variable
• Write so anyone knows what you are saying!!!!!!!

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Other Stuff

• On the Scientific Method Quiz, if your grade is
• 13-14 Awesome Job!!
• 11-12 Good, but needs some work.
• 7-10 OK, but what are you at a loss about?
• 0-6 Get help before the test Wednesday!!!
• On the Astronomy Quiz, if your grade is
• 19-20 Stellar Performance!!
• 18 Awesome Job!!
• 15-17 Good, but needs some work.
• 9-14 Ummmhhhh I think you need to study!!!
• Below a 9 Seek help before Wednesday test!!!

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The Golden Age Astronomers
Aristarchus (312-230BC)
Aristotle (384-322BC)
The Earth is round.
1st to believe in heliocentric universe