today’s comments d2l quiz 3 & 4 available (#4 has first few questions from next lecture) test...
TRANSCRIPT
Today’s Comments• D2L Quiz 3 & 4 available (#4 has first few questions from next lecture)• Test 1 on Feb. 10.
• Special tutor session with Gustavo: Thurs, Feb. 5, 3-5pm• Best test prep: 1. objectives, 2. D2L quizzes, 3. lectures/notes, 4.
book• Sunset – Part 1 Due Feb. 12 (in 2 weeks)
• Sunrise and Sunset times• http://www.timeanddate.com/sun/usa/minneapolis• Phone App: Sunrise Sunset
• Moon Phases Due Mar. 2 • Moon visible times: (Moonrise and Moonset)
• http://www.timeanddate.com/moon/usa/minneapolis• Phone App: Phases of the Moon Free
• Exploradome Planetarium Feb. 3 in T bldg plaza, 1st floor• 9am to 12pm – come for a 20-30 minute presentation, every half
hour. Shows at 9, 9:30, 10, 10:30, 11 and 11:30am.• Check-in with me. Counts for lecture that DAY & lab for the WEEK
Prior to the Copernican Revolution – Greek Astronomy
• Western only – Please investigate other cultures
• Greeks (influenced by Babylonia, Mesopotamia, Egypt, Rome)
• ~700 BC to ~140 AD• Some ideas and people
• Know the starred* items
Geocentric Model*(from Aristotle, 384-322BC)
Everything orbits around…
Earth Sun
Heliocentric Model* (from Copernicus, 1473-1543AD)
Prior to the Copernican Revolution – Greek Astronomy
~700 BC Early astronomy was about time keeping (when to sow and reap crops)
Prior to the Copernican Revolution – Greek Astronomy
Hesiad, Works and Days • ... when the Pleiades rise it is time to use the
sickle, but the plough when they are setting; 40 days they stay away from heaven; when Arcturus ascends from the sea and, rising in the evening, remain visible for the entire night, the grapes must be pruned;…
• Needed better observations to keep the various calendars synchronized.
Prior to the Copernican Revolution – Greek Astronomy
Greeks ~Fifth Century BC
• What is the sun? Fire?• Tiny lights in the sky?• Why do 7 lights wander
among the others? (7 Planetes*)
science.msfc.nasa.gov/ ssl/pad/solar/surface.htm
imagine.gsfc.nasa.gov/.../ news/22apr02.html
http://artsci.shu.edu/physics/1007/retro2.gif
Prior to the Copernican Revolution – Greek Astronomy
Pythagoras of Samos ~500 BC• Earth is a sphere• Sphere is perfection in math• Crystal spheres for 7 planetes
Sun, Moon, 5 others• Already thinking geocentric
http://library.thinkquest.org/C0126626/fate/geocentric.jpg
Prior to the Copernican Revolution – Greek Astronomy
Plato ~360 BC• Heavens are perfect, unchanging
(from mathematical perfection)• Heavenly motion must be in circles
and uniform
Prior to the Copernican Revolution – Greek Astronomy
Aristotle ~350 BC• Plato’s student• Earth: Corrupt, changeable, imperfect
(separation of heavens and Earth)• Arguments for geocentric model*
No parallax of stars*
and
Moon would be left behind*
• Parallax is the apparent change in position of an object due to the change in position of the observer– Parallax thumb demonstration
Prior to the Copernican Revolution – Greek Astronomy
Aristarcus ~300 BC• Heliocentric solar system
(first evidence)*• Measured size of Sun• Measured that Sun was much
further away than Moon
Prior to the Copernican Revolution – Greek Astronomy
Ptolemy ~140 AD• Geocentric model* (often called the
Ptolemaic system)• Mathematical model of universe*
– Perfect Bodies and orbits• circles,
spheres– Uniform motion– Epicycles*
(retrograde motion)*
From Moon LecturesAlready know this:• Minute to Minute: the Sun, Moon, stars, planets appear
to rise in East and set in West due to Earth’s spin (rotation).
• Day to Day: Moon moves West to East due to Moon’s orbit (revolution) around Earth.
New information:• Day to Day: Planets typically move West to East due to
their orbits around the Sun.• Retrograde Day to Day Motion: Planets move East to
West due to their orbits around the Sun and the difference in speeds of Earth and other planet.
Retrograde Motion (Day to Day)Sometimes planets moved backwards against the
background of stars.
Retrograde motion is East to West and observed day to day.
Minute to minute motion across sky is still East to West due to Earth’s rotation.
Mars’ Epicycle
PtolemyGeocentric ModelPerfect circles, spheres, uniform motion
Earth
Mars
Copernican Revolution
Both models explain observations…
Retrograde motion of planets
Copernican Revolution
Retrograde motion – Geocentric
Planets ride on epicycles
Sometimes appear
to move backwards
Copernican Revolution
Retrograde motion – Heliocentric
One planet overtakes
another planet.
Slower planet appears to
move backwards.
Copernican Revolution
•Retrograde (westward) motion of a planet occurs when the Earth passes the planet.
•Ptolemy’s epicylces unnecessary
Retrograde motion – HeliocentricNew (and correct) explanation of retrograde motion
of the planets.
Prior to the Copernican Revolution – Greek Astronomy
Dark Ages in Europe (5th to 15th centuries AD)
• Roman libraries sacked• Often violent mix of Latin and Arabic
cultures• Plague, famine, war • Islamic Golden Age of Science
Long time between Ptolemy ~140 AD to Copernicus ~1500 AD.
Summary
• Before Copernicus ~700BC to 140 AD
Geocentric Model Dominated– Pythagoras of Samos– Plato– Aristotle*– Aristarchus*– Ptolemy*
Observation Projects
OBSERVING PROJECTS (in order of due date) Each line below is worth 10 points for a total of 80 points.• Planetarium (Exploradome at MCTC): Feb. 3• Sunset – Part 1 Start: Jan. 20; Due: Feb. 12• Moon Phases Start: Jan. 22; Due: Mar. 3• Safe Sun Prep Work Start: Mar. 19; Due: Mar. 26+• Sunset – Part 2 Start: Apr. 2; Due: Apr. 28• Moon Craters Start: Jan. 29; Due: May 5• Star Gazing Start: Jan. 29; Due: May 5• Telescope Start: Jan. 29; Due: May 5
Observations• Star Gazing Observation
– Main Goal: See constellations in night sky
• Telescope Observation– Main Goal: Look at night sky through a telescope
• Moon Craters Observation– Main Goal: see Moon’s craters under magnification
• Jan. 29 to May 5 to complete• 7 Options for each of these 3 observations• Class website has more details.• Turn in verification sheet (unless you check-in with me at the
event).
6 Locations for Star Gazing, Telescopes & Moon Craters
• Options1. Eagle Lake Observatory at Baylor Regional Park (complete
star gazing and telescopes together and possible moon craters) - every other Sat. until Nov.• Easiest way to complete but about an hour drive & $5/car
2. Jackson Middle School Observatory (dates TBD) – Champlin, MN
3. Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call 952-988-4070 for reservations)
4. University of MN (Fridays TBD) – Minneapolis, MN
5. Macalester College (Thursdays TBD) – St. Paul, MN
6. St. Thomas College (weeknights TBD) – St. Paul, MN
7th Option (at home) forStar Gazing, Telescopes &
Moon Craters• Star Gazing Observation
– Star gaze with friends and write a short report
• Telescope Observation– Use your/friends’ telescope and write a report (talk to
me)
• Moon Craters Observation– Use binoculars (from my office) and write short report
Star Gazing Observation• Main Goal: See constellations in night sky• Jan. 29 to May 5 to complete• 7 Possible Options
Must have an expert point out constellations OR write a report1. Eagle Lake Observatory at Baylor Regional Park (complete star
gazing and telescopes together and possible moon craters) – every other Sat. until Nov.• Best view and experience but about an hour drive & $5/car
2. Jackson Middle School Observatory (date TBD) – Champlin, MN3. Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm
(call 952-988-4070 for reservations)4. University of MN (Fridays) – Minneapolis, MN5. Macalester College (Mondays or Thursdays) – St. Paul, MN6. St. Thomas College (weeknights TBD) – St. Paul, MN7. Star gaze with friends and write a short report
• Class website has more details.• Turn in verification sheet.
Telescope Observation• Main Goal: Look at night sky through a telescope• Jan. 29 to May 5 to complete• 7 Possible Options
1. Eagle Lake Observatory at Baylor Regional Park (complete star gazing and telescopes together and possible moon craters) - every other Sat. until Nov.• Best view and experience but about an hour drive & $5/car
2. Jackson Middle School Observatory (dates TBD) – Champlin, MN
3. Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call 952-988-4070 for reservations)
4. University of MN (Fridays TBD) – Minneapolis, MN
5. Macalester College (Thursdays TBD) – St. Paul, MN
6. St. Thomas College (weeknights TBD) – St. Paul, MN
7. Use your/friends’ telescope and write a report (talk to me)
• Class website has more details.• Turn in verification sheet.
Moon Craters Observation• Main Goal: see Moon’s craters under magnification• Jan. 29 to May 5 to complete• 7 Possible Options (Must have visible Moon, ideal is half Moon)
1. Eagle Lake Observatory at Baylor Regional Park (complete star gazing and telescopes together and possible moon craters) - every other Sat. until Nov.• Best view and experience but about an hour drive & $5/car
2. Jackson Middle School Observatory (dates TBD) – Champlin, MN
3. Eisenhower Community Center (dates TBD) – Hopkins, MN 7-10pm (call 952-988-4070 for reservations)
4. University of MN (Fridays TBD) – Minneapolis, MN
5. Macalester College (Thursdays TBD) – St. Paul, MN
6. St. Thomas College (weeknights TBD) – St. Paul, MN
7. Use binoculars (from my office) and write short report
• Class website has more details.• Turn in verification sheet.