peer led instruction - woubrownk/es104/es104.2007.1002... · 2007. 10. 2. · lab starts this...
TRANSCRIPT
1
Celestial Motion
Chapter 21, pages 597-606Chapter 22, pages 615-619
Lab starts this week—NS 017
Peer Led Instruction
• Library—Wednesday 6:30 to 8:30 PM• Kristin Mooney—Science Education Major• Add ES104X—CRN 11017
• Can add before Oct. 3 session– Do review questions to see if you think it help– Sit in to see if it is for you
Get your lab manual
• Do Prelab 1 and bring to lab class• Lab starts with activities this week• Make-ups are difficult to accomplish, so be
sure to attend your lab regularly• Must pass lab to pass class
Tycho Brahe
• Detailed observations of movement of planets
http://www.hao.ucar.edu/public/education/sp/images/tycho.html
Tycho Brahe in his
observatory• His careful
observations and records are his most important legacy
http://www.hao.ucar.edu/public/education/sp/images/tycho.3.html
Tycho’s 1572 Nova
observations
http://www.hao.ucar.edu/public/education/sp/images/tycho.1.html
2
Tycho’s comet of 1577
http://www.hao.ucar.edu/public/education/sp/images/tycho.2.html
Tycho’smodel of
solar system
• Discounted Copernicus model because he could not discern stellar parallax
• It does exist, he didn’t have tools to see it
http://www.hao.ucar.edu/public/education/sp/images/tycho.4.html
Johannes Kepler
• Tycho’s assistant and successor
• Used Tycho’s data to determine planetary orbits are elliptical
http://en.wikipedia.org/wiki/Image:Johannes_Kepler.jpg
First Law of Planetary Motion
• Orbit of planet is ellipse
• Sun at one Focus
Kepler’s 2nd Law
• Equal areas in equal time intervals accounts for the uneven speeds
Kepler’s third law of planetary motion
• p2=d3
p=Period (time to orbit Sun) in Earth yearsd=Distance in Astronomical Units:
1 A.U.=distance from Earth to Sun
3
Galileo Galilei• Strong supporter of
Copernican model of planetary movement
• Built 30x telescopes (from descriptions of the devices) and looked at planets and Moon starting in 1609
http://en.wikipedia.org/wiki/Galileo_Galilei#Technology
Galileo’s notes on Jupiter’s moons
• Telescope used to see that another body in solar system is a center of orbital movement
• These moons are not left behind, and Earth’s Moon is not either
Ptolemaic version of Venus Phases of Venus
Galileo’s explanation of Venus’phases Moon’s surface has texture
4
Galileo’s Astronomical Discoveries
• When viewed by telescope, planets look like discs, not points of light as stars do
• Jupiter has moons• Venus has phases• Moon’s surface has texture• Sun rotates on an axis
Foucault’s Pendulum
• 1851• Proved Earth does rotate on
its axis—Copernicus’hypothesis
Isaac Newton
• Invented the calculus to simplify calculations
• Explained the orbital motion of planets as the interaction of inertia and gravity
Orbital motion of planets
Brief Review
• Sun is at the center of the solar system• Published by Copernicus
– Supported by Galileo’s telescopic observations of Jupiter and Venus
• Kepler determined orbits are ellipses• Newton determined orbits created by
interaction of inertia and gravity
Constellations
• Star groups• 88 recognized• Stars names by brightness in them
5
Orion
• Southern Sky• Hunter• White Tiger
• http://lithops.as.arizona.edu/~jill/EPO/Posters/Orion/protoplanets.html
Star names in Orion
• http://borghetto.astrofili.org/costellazioni/costellazioni.htm
Orion’s place in the sky
• Bright star to lower left of Orion is Sirius
• http://www.windows.ucar.edu/the_universe/images/starmaps/map_orion.jpg
Sirius
• “The Dog Star”• Brightest star in sky• In Canis Major
• http://www.windows.ucar.edu/cgi-bin/tour_def/the_universe/images/starmaps/map_canis_major_jpg_image.html
Arcturus• Second brightest
in northern sky• Very large• Rather cool
• http://www.windows.ucar.edu/cgi-bin/tour_def/the_universe/Arcturus.html
• http://en.wikipedia.org/wiki/Arcturus
Celestial position
6
Earth turns pointed at Polaris Polaris and Big Dipper
Polaris and Big Dipper Polaris and Big Dipper
Polaris and Big Dipper—each 8 hours What is a ‘day’?
• Mean Solar Day
7
What is a ‘day’?
• Sidereal Day
• Incredibly distant stars—closest is 60,000+ times further than Sun
What is a ‘day’?
• Mean Solar Day—24 hours• Sidereal Day—23 hours, 56 minutes
Plane of the eclipticAnimation of equinox and
solstice
Equinox and solstice related to the plane of the ecliptic Constellations on the ecliptic
8
Axial wobble--precession
• http://video.google.com/videoplay?docid=4242610371139275474&q=precession+of+equinox&total=54&start=10&num=10&so=0&type=search&plindex=4
Lab Starts this Week
• Room NS 017• Down the south stairs• Do not miss class the first week• Buy your lab manual and read the first lab• Do the prelab questions, because your lab
instructor may want you to hand them in
Animation link -- http://www.astro.virginia.edu/class/oconnell/astr121/im/lunation-anim.gif
Moon’s Motion
• Rotates on axis once each 27 1/3 days• Same side always faces Earth• No atmosphere—extreme temperature
variation: 127o to -173o C
9
Moon
• 3475 km diameter
• Density ~ Earth’s mantle
http://www.astrosurf.com/cidadao/moon_99_03_01.jpg
Meteor Impact Compression Wave
10
Ejecta Rim Euler Crater
Lunar Features Maria Formation
Flood Basalt Lunar Exploration
11
Footprint in lunar regolith
Moon formation
http://www.psi.edu/hartmann/pic-cat/
Impact of asteroid
http://www.psi.edu/hartmann/pic-cat/
Ejecta from impact
http://www.psi.edu/hartmann/pic-cat/
Coalesced to form Moon
http://www.psi.edu/hartmann/pic-cat/
Moon was initially hot
http://www.psi.edu/hartmann/pic-cat/
12
Moon by Apollo
17 CrewRight part of
photo is ‘dark side’that cannot be seen from Earth
http://spacekids.hq.nasa.gov/osskids/animate/moon.html
Rayed Crater
http://cnr2.kent.edu/~manley/copernicus_crater_area.jpg
Lab Starts this Week
• Room NS 017• Down the south stairs• Do not miss class the first week• Buy your lab manual and read the first lab• Do the prelab questions, because your lab
instructor may want you to hand them in