Observations of the sky Observations of the sky Observations of the Sky Observations of the Sky What patterns, motions, and events What patterns, motions, and events do we notice in the sky? do we notice in the sky? What theories can we create to What theories can we create to explain them? explain them? How can these theories be tested? How can these theories be tested?
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Observations of the skyObservations of the sky
Observations of the SkyObservations of the Sky
What patterns, motions, and events do we What patterns, motions, and events do we notice in the sky?notice in the sky?
What theories can we create to explain them?What theories can we create to explain them?
How can these theories be tested?How can these theories be tested?
Observations of the skyObservations of the sky
WHAT DO YOU THINK?
1.1. Is the North Star—Polaris—the brightest star in Is the North Star—Polaris—the brightest star in the night sky?the night sky?
2.2. How many zodiac constellations are there?How many zodiac constellations are there?
3.3. What causes the seasons?What causes the seasons?
4.4. Does the Moon have a dark side that we never Does the Moon have a dark side that we never see from Earth?see from Earth?
5.5. Is the Moon ever visible during the daytime?Is the Moon ever visible during the daytime?
6.6. What causes lunar and solar eclipses?What causes lunar and solar eclipses?
Observations of the skyObservations of the sky
ConstellationsConstellations
Groupings of stars in the same direction Groupings of stars in the same direction
Pattern repeats every yearPattern repeats every year
Orion Leo
Observations of the skyObservations of the sky
Constellations by familiar shapes & by definition of regions
Observations of the skyObservations of the sky
Constellations as guides !
Observations of the skyObservations of the sky
Constellations in the Summer
Observations of the skyObservations of the sky
Constellations in the Winter
Observations of the skyObservations of the sky
Measuring the sky with angles…
Observations of the skyObservations of the sky
Observations of the skyObservations of the sky
Time-lapse photo looking North! WHY???
Observations of the skyObservations of the sky
““Circumpolar”Circumpolar” Constellations Constellations
Some constellations always visibleSome constellations always visible
… … and they rotate around Polarisand they rotate around Polaris
Observations of the skyObservations of the sky
Finding your Latitude!Finding your Latitude!
The HEIGHT of Polaris indicates LatitudeThe HEIGHT of Polaris indicates Latitude
Altitude angle
Observations of the skyObservations of the sky
How the sky moves at the north pole over time…
Stars don’t set!
Observations of the skyObservations of the sky
How the sky moves at the equator over time…
Stars set straight DOWN
Observations of the skyObservations of the sky
How the sky moves at a latitude like Hayward…
Observations of the skyObservations of the sky
The SunThe Sun
Rises in the East, sets in the West…Rises in the East, sets in the West…
… for *most* observers, but not all!… for *most* observers, but not all!… not always due East, nor due West!… not always due East, nor due West!
D Parkinson
Observations of the skyObservations of the sky
The SunThe Sun
It takes about 24 hours to repeatIt takes about 24 hours to repeat
How it rises & sets depends on position!How it rises & sets depends on position!
Near Equator, almost straight up/downNear Equator, almost straight up/downNear Poles, very “shallow” angle!Near Poles, very “shallow” angle!
Observations of the skyObservations of the sky
Seasonal PatternsSeasonal Patterns
Height of Sun varies over the yearHeight of Sun varies over the year
It gets hot in summer, and cold in winter!It gets hot in summer, and cold in winter!
Observations of the skyObservations of the sky
Seasonal PatternsSeasonal Patterns
Summer:Summer:Sun higher in the sky, shining more DIRECTLYSun higher in the sky, shining more DIRECTLYSun up longer, more hours in the daySun up longer, more hours in the day
Winter:Winter:Sun lower in the sky, less direct lightSun lower in the sky, less direct lightSun not up as longSun not up as long
Does DISTANCE matter??Does DISTANCE matter??
Observations of the skyObservations of the sky
Seasonal PatternsSeasonal Patterns
Sun’s “speed” across the sky variesSun’s “speed” across the sky varies
The “analemma” is famous…The “analemma” is famous…
lower loop = Winter, Earth moves faster in its orbit
Upper loop = Summer, Earth moves slower in its orbit
Observations of the skyObservations of the sky
Seasonal PatternsSeasonal Patterns
Bergamo, ItalyBergamo, Italy
Photos by John Nystuen, University of Michigan
Observations of the skyObservations of the sky
Process of Science Example!Process of Science Example!
ObservationsObservationsSeasons! Seasons! (hot, cold patterns that repeat yearly)(hot, cold patterns that repeat yearly)
ResearchResearch Happens every yearHappens every year
Building Testable Theories & HypothesesBuilding Testable Theories & Hypotheses Sun’s distance causes seasons?Sun’s distance causes seasons?
Do the experimentDo the experiment Sun is closer in northern winter!Sun is closer in northern winter!
Throw out the hypothesis! Revise the theory!Throw out the hypothesis! Revise the theory!
Observations of the skyObservations of the sky
Process of Science Example!Process of Science Example!
More ObservationsMore ObservationsEarth “tilts” towards polarisEarth “tilts” towards polaris
More ResearchMore Research 23. 5 degrees23. 5 degrees
Building Testable Theories & HypothesesBuilding Testable Theories & Hypotheses Earth tilts “closer” to the sun to create summer?Earth tilts “closer” to the sun to create summer?
Do the experimentDo the experiment Earth’s orbit is elliptical – still MUCH closer in JanEarth’s orbit is elliptical – still MUCH closer in Jan
Throw out hypothesis again!Throw out hypothesis again!
Observations of the skyObservations of the sky
Process of Science Example!Process of Science Example!
STILL More observations!STILL More observations!Sun’s height changing, length of day variesSun’s height changing, length of day varies Southern Hemisphere seasons reversedSouthern Hemisphere seasons reversed
ResearchResearch Absorption of Solar RadiationAbsorption of Solar Radiation
Building Testable Theories & HypothesesBuilding Testable Theories & Hypotheses Earth’s tilt creates seasonsEarth’s tilt creates seasons
Do the experimentDo the experiment Seasons on other tilted planets? Yes!Seasons on other tilted planets? Yes!
Publish, continue the process….Publish, continue the process….
Observations of the skyObservations of the sky
The planetsThe planets
Five objects move relative to the ZodiacFive objects move relative to the Zodiac
Each does it differently, at different times Each does it differently, at different times but eventually, you can see a but eventually, you can see a patternpattern..
Tunc Tezel, apod031216
Observations of the skyObservations of the sky
The MoonThe Moon
A sequence of repeated phases over A sequence of repeated phases over about a “moonth”about a “moonth”
Observations of the skyObservations of the sky
The “wobble” of Earth…The “wobble” of Earth…
Precession changes direction Earth’s Precession changes direction Earth’s rotation axis points in the skyrotation axis points in the sky
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