History Astronomy is perhaps the oldest science. Stargazing came before language, before fire. What is “our” place in the universe and how do we fit in?

History

• Astronomy is perhaps the oldest science.

• Stargazing came before language, before fire.

• What is “our” place in the universe and how do we fit in?

Modern Event Calendars

S M T W T F S

1 2 3 4 5 6 7

8 9 10 11 12 13 14

15 16 17 18 19 20 21

Astronomical Event Recorded

Observatories• a) Big Horn Medicine Wheel (Montana)• b) Mayan Caracol (Mexico)

Big Horn• The Big Horn Medicine Wheel in the Big Horn Mountains

near Sheriden, Wyoming was interpreted in 1974 as an indicator of summer solstice sunrise and sunset, with other alignments for the rising of certain stars (Aldebaran, Rigel, and Sirius).

• Built about 1050 AD. Has 28 spokes, and is about 90 ft in diameter.

• About 50 similar circles exist. The oldest is in Canada (built about 2500 BC - at the same time as the Egyptian pyramids).

Caracol• Located at Chichen Itza, Yucatan, Mexico, the

Caracol Tower was built about 1000 AD.

• It has some solstice and equinox alignments, and also some star alignments. More interesting are the apparent alignments with Venus (one of their "gods").

• Mayan tablets also mention the rising of Venus. The alignments make sense in light of the written records.

Caracol

Big Horn

Stonehenge• Stonehenge (England)• Inset displays sunrise on the summer solstice as seen from

the center looking east toward the heel stone.

Stonehenge• Consists of several concentric circles built in three periods, beginning

about 2800 BC.

• The largest stones weigh 50 tons, and were transported from many miles away.

• Viewed from the center, the sun rises over the heel stone at the summer solstice. (This was first noted in modern history in 1771.)

• Many other alignments are verified by astronomical planetarium computer simulations.

Sun Dagger, Aztec Calendar Stone

Sun Dagger• Discovered in 1977.

• Anasazi Indians of Chaco Canyon, New Mexico constructed a spiral rock carving on Fajada Butte.

• At noon on the summer solstice, a dagger of sun penetrates the center of the spiral.

• On the autumnal equinox, a sun dagger passes through the center of a small spiral on the left, and another passes on the edge of the large spiral. At the Winter Solstice, a big sun dagger passes on either side of the large spiral.

• Also marks a 19-year lunar cycle. (The spiral has 19 rings.)

Mounds

• Cahokia Mounds in southern Illinois near East St. Louis has a circle of postholes interpreted in 1970 as an astronomical indicator of summer solstice sunrise, winter solstice sunrise, and equinox sunrise.

• The mound-building Indians in the Mississippi Valley region began about 3000 years ago, and there were several cultures, and three successive groups of Indians there. There is much conjecture about their circles, but little organized

study.

Ancient Astronomer (Astrologers)Arab Astronomers

at work keeping

the nobles

informed and

entertained.

A mix of science and

pseudo-science.

Astronomers and Astrologers• In the ancient world Astronomers paid their bills and funded

their scientific pursuits by – predicting astronomical events for nobles

• eclipses

• tides

• comets

• planetary motions

– casting horoscopes

– entertaining

• Astrology, although totally bogus, was good economics!

Astronomy Versus AstrologyAstrology is an ancient superstition that hold that a person’s personality

and actions are influenced by the positions of the sun, moon, planets, and stars at the moment of birth. In addition, astrologers claim that the daily changes in the location of heavenly bodies can influence events in our everyday lives. All of this is summarized in a horoscope, which includes a diagram of the zodiac, showing the precise positions of the heavenly bodies in their orbits.

Is there any physical reason we should expect astrology to work, except that it might appeal to our needs? There seems to be no way for the various heavenly bodies to interact on the body of a baby at birth, except via gravity. The force of gravity exerted on the baby by the doctor is many times larger than that of the sun and planets. Thus, it would seem more important where the doctors and nurses stand in the room rather than the orientation of the sun, moon, mars and the earth.

Astronomy Versus AstrologyIs there any evidence that astrology does work? Astrology has been

tested many times over, and no legitimate test has proven any astrological influence on our lives. Extensive tests have searched in vain for relationships between birth date and profession, blood type, handedness, divorce rate, etc.

Yes it is based on science: Positions via Celestial Mechanics

It is NOT a science. It can not make accurate, verifiable predictions.

NO it doesn’t influence our lives: Use it like you would flipping a coin or for entertainment along with the Sunday Funnies or fortune cookies.

Astronomy Versus Astrology TOP 10• 10. Astronomers never try to contact dead Astrologers.


• 9. Politicians wives never asked an astronomer for advice.



• 8. The positions of the stars, planets, etc. dictate an astronomer’s evening observing schedule, but they dictate all aspects of an astrologer’s life.




• 7. Telescopes come in a staggering array of shapes and sizes. All Ouija boards look the same.




• 7. Telescopes come in a staggering array of shapes and sizes. All Ouija boards look the same.

• 6. Carl Sagan did not have a 900 number.

Astronomy Versus Astrology TOP 10• 5. Your VISA limit is of very litter interest to an

astronomer.


astronomer.• 4. Astronomers occasionally make accurate predictions.


astronomer.• 4. Astronomers occasionally make accurate predictions.• 3. Alcohol makes complex astronomical concepts more

difficult to comprehend. It makes astrological concepts easier.




• 2. Transposing two astronomical objects’ coordinates makes a huge difference. Transposing two peoples’ horoscopes makes no difference at all.




• 2. Transposing two astronomical objects’ coordinates makes a huge difference. Transposing two peoples’ horoscopes makes no difference at all.

• 1. Astronomers believe in the truth of relativity. Astrologers believe in the relativity of truth

The Scientific Method

Iterative Logic and Creativity

“Right-brain” thinking “Left-brain”

thinking

Science Questions• Science is only interested in questions that have an

experimentally verifiable end.

• There must be a Test for wrongness or rightness.

• If there is nothing experimentally verifiable, there is no science.

• Not interested in speculations, only what can and can not happen.

• Beware Pseudo-Science (Astrology)• Extraordinary Claims Require Extraordinary Evidence!

Our Place In the CosmosAristotle and Ptolemy

Geocentric Theory

(Earth Centered View)

Copernicus and Galileo

Heliocentric Theory

(Sun Centered View)

Aristotle’s Perfect Spheres

Developed the firstaccurate star atlas, completewith brightness assignments.

Taught the perfection of theheavens, spheres, and natural circles introducedby Aristotle.

Geocentric “Earth-centered”Universe.

Ptolemy

The Enigma of the Planets

The retrograde loop of Mars.

Planos ~ wanderer

The retrograde loops of other planets overthe course of a year.

Epicycles

Explaining planetary

motion in a

geocentric model

of the universe using

perfect circles

was not easy.

Geocentric Solar SystemThis allowed the

earth to be

stationary in space,

in the center of

the universe, and

would describe

some of the

motions of the

heavens.

Retrograde Motion

• Mars Retrograde Motion

• Epicycles (Geocentric View)

Real Retrograde Motion

• Mars Motion (Heliocentric Theory)

Eratosthenes

Lived in Alexandria Egypt at the height of its glory as the

center of intellectual learning and knowledge in the ancient

world.

He learned from a friend, of a water well in Syenne Egypt,

near Aswan to the south. On a certain day of the year, the

city celebrates summer. On that day at noon, the sun does

not cast any shadows and you can see sunlight reflected

from the bottom of most wells.

Eratosthenes knew that no such day existed in his town of

Alexandria.

Models and Experimental Verification

The earth is round? The earth moves? Ludicrous?!

Eratosthenes KnewThe moon and sun are round.

During lunar eclipses, earth’s shadow on the moon is round.

Models and Experimental Verification

How big is the earth. How fast is it going?



Ships at sea appear mast first and disappear mast last.

Sailing, sailing, over the ocean blue...





























The earth is round?

Eratothenes KnewThe moon and sun are round.



Hire a Runner to Step out the Distance

Stadia (unit of measure ~ football field (Roman Coliseum))

Size of the Earth

3600 = Circumference of the Earth

70 Distance from Alexandria to Syenne

What is the distance from

Alexandria to Syenne?

Earth As A Sphere

Circumference of the earth = (360/7) 50,000

= 24,000 miles

For ~ 3

and D = 2 x Radius

2 R = 24,000

R = 24,000/6

R ~ 4,000 miles Radius of the Earth

Scientific Analysis

Eratosthenes had measured the size of the earth to within 10%

of the actual value. Quite a feat.

But, science is not only about answering a question (how big

is the earth?), but following up on the consequences of the

theory or model.

If the earth is a sphere with a radius of 4,000 miles, what are

the consequences?

Consequences

Perhaps we can not believe the earth is flat. It must be a

sphere. But, at least let us believe it sits motionless at the

center of the universe with the stars and planets revolving

around us.

OTHERWISE…

Distance = Speed x Time Distance = Circumference

Speed = v

Time = period of rotation

Consequences

Perhaps we can not believe the earth is flat. It must be a

sphere. But, at least let us believe it sits motionless at the

center of the universe with the stars and planets revolving

around us.

OTHERWISE…

Distance = Speed x Time Distance = Circumference

Speed = v

Time = period of rotation

D = 24,000

t = 24 hours

Calculating Rotation Speed

D = v t

2 R = v t

2 (4,000 miles) 3 = v (24 hours)

Do You Feel FAST!

D = v t

2 R = v t

2 (4,000 miles) 3 = v (24 hours)

24,000 miles = v 24 hours

24,000 miles = v

24 hours

v = 1,000 miles/hour

Predictions

Spherical, Rotating Earth: Someone at the equator must move

at 1,000 miles/hour.

Experimental Verifications of the Rotating Earth:– Focault Pendulum

– Coriolis Effect

– Planetary Motions

DEFENDER OF COPERNICAN HELIOCENTRIC THEORYI. Craters on the Moon (imperfection)

II. Sunspots on the Sun (imperfection and solar rotation) III. The Moons of Jupiter (earth is not the center of all things) IV. The phases of Venus I-III Represent Circumstantial evidence IV DNA/fingerprints, undeniable proof

Galileo’s Observations

Galileo’s Phases of VenusHeliocentric

Geocentric

Galileo’s Phases of VenusGeocentric

versus

Heliocentric

Galileo and the Inquisition

Heliocentric Retrograde Motion of Mars

Planetary Scale Model•

Solar System Scale ModelPlanet Solar Distance (AU) Relative Size (Earth =1.0) Inches Object

SUN 0.0 100 McEver Hall

Mercury 0.4 0.4 4 Baseball

Venus 0.7 1.0 10 Basketball

Earth 1.0 1.0 10 Basketball

Moon 1.0 0.3 3 Racquetball

Mars 1.5 0.5 5 Softball

Jupiter 5 11 110 Golf Cart

Saturn 10 9 90

Uranus 20 4 40 Bean Bag

Neptune 30 4 40

Pluto 40 0.2 2 Golf ball

Shapley’s Globular Cluster Distances

OrdinaryEach successive discovery removes us from a special place in

the universe.

More and more observations indicate that we (and earth)

are ordinary, even insignificant when compared to the vastness

of space.

We are a minor planet, around an average star, in an average

galaxy.

A Stellar Zoo

Solar NeighborhoodThe Sun

(an average star)

and the stars

within 4 parsecs.

The Milky Way

You Are Here

One Galaxy Among Many

A Slice of the UniverseEach dot

represents

one galaxy.

Universe Scale•

Scales and Sizes

• MOVIE: Powers of 10

Summary

History Astronomy is perhaps the oldest science. Stargazing came before language, before fire. What is “our” place in the universe and how do we fit in?

Documents

caracol slide

big horn slide

aztec calendar stone

winter solstice sunrise

equinox alignments

big horn mountains

equinox sunrise

large spiral