Today is Tuesday,April 28th, 2015

Pre-Class:Take a guess as to what year the telescope was

invented. We’ll see who gets closest.

http://www.ichundmeinmitbewohner.de/wp-content/uploads/2013/05/mauna-kea-2.jpg Mauna Kea Observatories, HI

In This Lesson:Unit 2

The History of Astronomy

(Lesson 1 of 2)

Today’s Agenda

• Early astronomers.• Kepler, Galileo, Copernicus vs. Catholic Church– Guess who wins?

• How to die from holding your pee.

• Where is this in my book?– Pages 47-56.

By the end of this lesson…

• You should be able to narrate a brief history of astronomy through the ages and across cultures.

• You should be able to construct an accurate model of a planet’s elliptical orbit.

Astronomy Through The Ages

• I’ve said this before, but astronomy is a very old science.– Chemistry really didn’t get going in earnest till at least

the 1700s.– Biology had its biggest early discoveries in the 1800s.– Physics took off in the 1900s (Newton

notwithstanding).• But astronomy…just look up and there it is.– We’ve been doing this for a long time.

Astronomy Through The Ages

• There’s a downside to the immediacy of astronomy, though:– It’s easy to misinterpret.

• We’ve already seen it with Harvard grads attempting to explain the seasons and instead pooping the bed.

• Even now we see pretty embarrassing astronomical train wrecks, like this one:– Isaac Mizrahi Live – The Moon

Astronomy Through The Ages

• Beyond appallingly uninformed designers and their TV co-hosts, people have also associated the Moon with all kinds of phenomena.

• For example, how many times have you heard, “it must be a full moon” or something to that effect?– As a matter of fact, someone that’s completely

bananas might be called a lunatic, and that stem word is not a coincidence.

So where do we begin?

• Let’s go back to the beginning of recorded astronomical history.

• We’ll look at the good and the bad, the ingenious and the inane, the science and the…

• …Catholic Inquisition?– We’ll get to it.

Early Man

• Some of the earliest evidence of mankind’s interest in the sky comes from drawings like the Pueblo Petroglyphs.– Drawings of eclipses, comets,

and supernovae have been uncovered.

• Generally speaking, however, early man had little to do with astronomy.

Moving Forward

• As time progressed, astronomy began to take on a religious role.– The heavens (see what I mean?) were thought to

hold a power over existence on Earth.• Harnessing that power would mean an ability

to predict and explain various events.• We see this even today with astrology and

horoscopes.– P.S. Virgo, your day is a 9.

The Babylonians

• The Babylonians (~1600 BC) are among the first to actually record stuff.– Positions of

planets, times of eclipses…stuff like that.

http://www.sunflowercosmos.org/astronomy/history_astronomy/3_babylonian_tablet.jpg

The Greeks

• The Greeks (the Hellenistic Culture; ~500 BC) inherited the astronomical records of the Babylonians and started to move things forward.

• They began to construct a cosmological framework.– The sky began to move from just a tool for navigation

and other practical things to a source of experimentation and exploration.

– They even knew the Earth was spherical, since the shadow of the Earth on the Moon was always circular.• Eat it, Magellan.

The Greeks

• What’s more, the Greeks took note that seven celestial objects moved, unlike the background stars.

• They called them planetes (“wanderers”) and we have since named our days of the week after them – you may need to think of their Romance language words:– The Sun (Sunday)– The Moon (Monday)– Mars (Tuesday – Day of Mars)– Mercury (Wednesday – Day of Mercury)– Jupiter (Thursday – Day of Jupiter)– Venus (Friday – Day of Venus)– Saturn (Saturday – Day of Saturn)

The Greeks

• Thales (~480 BC) became the first to predict eclipses using information dating to the Babylonians.

• Eratosthenes (~220 BC) became the first to measure the circumference of the Earth, and the way he did it is truly awesome:– TED: Adam Savage – How Simple Ideas Lead to

Scientific Discoveries

Aside: Geometry• “Geo-” is the stem word for

Earth stuff, right?– “Geography” is the study of

locations on Earth.– “Geology” is the study of the

abiotic Earth.– “Geometry” is math with

shapes…wait, what?• Turns out, “geometry” literally

means “Earth measure” and comes from Eratosthenes’ observations.

http://archive.wired.com/images/article/full/2008/06/circumference_eratosthenes_500px.jpg

The History of Astronomy

• In what today is England, early astronomers built Stonehenge.

• Stonehenge appears to be a rather primitive “computer” for determining the position of the planets and the Sun.– Which in turn provided the

native people with the ability to plan their seasonal pagan shindigs.

– Seriously, on the summer solstice, the Sun lines up with some of the stones perfectly.

• Man Builds Stonehenge video

The History of Astronomy

• Islamic astronomers contributed to astronomy many names for bright stars, words like zenith, and, notably, algebra.

The Mayans• El Caracol (“the snail” – named

for a spiral inner staircase) is an observatory in Mexico built by the Mayans.

• Its windows line up perfectly to view Venus, in which the Mayans took great interest.

• Notably, the Mayans (and Chinese) were very good at predicting eclipses despite having different calendars than we use today.

http://www.astro.virginia.edu/class/oconnell/astr121/im/El-Caracol.jpg

Native Americans• Bighorn Medicine Wheel, in the

Bighorn Range of Wyoming, lies at elevation 9642’.– Throughout most of the year it’s snow-

covered.• It’s a wheel, 80’ in diameter,

constructed out of stones 300-800 years ago.

• At end of each of the spokes are large stones, and each stone denotes a location where an important constellation rises or where the Sun rises during the summer solstice.

http://upload.wikimedia.org/wikipedia/commons/9/91/MedicineWheel.jpg http://solar-center.stanford.edu/AO/bighorn.html

The Big Leap Forward

• As you might guess, it’s kinda hard to “do astronomy” without such a fundamental instrument as a telescope.– Like Ron Burgundy, its invention was kind of a big deal.

• Today, we even have telescopes in space.– Lookin’ at you, Hubble.

• Before we transition from significant cultures to significant individuals within the field of astronomy, let’s look at the history of the telescope.– Let’s also get a little note organizer ready: The Copernican

Revolution.

The Invention of the Telescope

• Hans (Johan) Lippershey is generally regarded as the inventor of the first telescope.– Interestingly, Zacharias Janssen and his

son Hans, inventors of the first light microscope, claimed credit for inventing the telescope too.

• His patent application (which was denied by the government of Belgium) was submitted in 1608.

• With that, astronomy was launched (pun) into a new era. http://micro.magnet.fsu.edu/optics/timeline/people/lippershey.html

Hans Lippershey

Important Individuals

• With the telescope having become available as a tool, things really started to take off.

• Individuals, rather than cultures, began to become quite well known for what they were discovering.

http://smarthistory.org/assets/images/images/wright.jpg

Aristarchus (310-230 BC)

• Aristarchus of Samos was an ancient Greek astronomer.

• He figured out the relative sizes of the Earth, Moon, and Sun.

• Given that the Earth was found to be much smaller than the Sun, the Earth must revolve around the Sun.– You heard me right.– Aristarchus had the “Sun at

the center” thing in mind a long time ago.

http://www.hudsonvalleyalmanacweekly.com/wp-content/uploads/2012/07/ARISTARCHUS-@.jpg

Aristarchus of Samos(ahead of his time)

Ptolemy (AD 90-168)

• No one knows much about this Ptolemy dude.

• What’s best-known about Ptolemy is that he first popularized the idea of a geocentric solar system.– Geocentric = Earth-centered.

• He put this forth in his work Almagest and it took until the 1500s for Nicolaus Copernicus to set the record straight.– The catch? The Catholic Church kinda got

attached to the whole geocentric thing.– Fan, prepare to meet S---. http://upload.wikimedia.org/wikipedia/commons/

0/0b/PSM_V78_D326_Ptolemy.png

Ptolemy(tellin’ you not to do that)

Nicolaus Copernicus (1473-1543)

• Copernicus set forth the idea of the heliocentric solar system in De Revolutionibus.– Heliocentric = Sun-centered.– This was the beginning of the

Copernican Revolution.• Copernicus dedicated the book to

Pope Paul III and knew he was going to cause some trouble.– Most of that trouble got displaced

onto Mr. Galilei.• His weakness? He insisted orbits

were circular.

Nicolaus Copernicus(didn’t know to look at the

camera when taking a selfie)

Aside: Helium

• Every element on the periodic table emits a characteristic set of light wavelengths.

• Scientists can use that “light signature” to identify unknown elements.

• When analyzing light from the Sun, astronomers found a unique pattern of wavelengths.– Since at the time there was no known counterpart to the

element on Earth, scientists named it for the Sun:• Helium (same word stem as “Heliocentric”).

• Helium is the only element to have been discovered somewhere other than Earth.

Galileo Galilei (1564-1642)• Galileo made his own telescope

(scientific badass, even though it wasn’t as powerful as even binoculars are today).

• He saw Venus going through various phases, along with moons orbiting Jupiter, not Earth.– In addition, he observed sunspots directly,

which led to complete blindness late in life.• So Galileo supports the Copernican

System, which by this point had been labeled as heresy by the Church.– Cue the Inquisition.

Galileo Galilei(“…more than any other

single person, was responsible for the birth of

modern science.”) – Hawking

The Galileo Mess• Galileo’s statements erupted

into a big mess in 1633 after he published a book championing the Copernican System.

• As a result, Galileo was under house arrest for eight years, dying in captivity at age 77, completely blind.

• It took until 1992 for the Pope/Vatican to formally excuse Galileo for being correct.

Tycho Brahe (1546-1601)

• Tycho Brahe (pronounced “Tie-co Bra-hey”) made his observations from Hveen Island in Denmark.

• He’s credited for having some of the most accurate observations of the position of the stars and planets.– And he did it without a telescope,

but with giant instruments. Tycho Brahe(with early hipster ‘stache)

Tycho Brahe (1546-1601)

• Pretty cool, except despite knowing of Copernicus’s discoveries, he believed the Sun revolved around the Earth, and the rest of the planets revolved around the Sun.– He still couldn’t see parallax in the

stars.• That was detected in the 1800s.

– Brahe’s model still explained the phases of Venus as confirmed by Galileo. Brahe’s Naked-Eye Observatory

The Tychonic Solar System

http://www.polaris.iastate.edu/EveningStar/Unit2/unit2_sub3.htm

Aside: Tycho was a Weird Dude

• Fun facts (or possible facts) about Tycho Brahe:– He lost part of his nose in a duel with

another astronomy student and wore a brass insert for the rest of his life.

– In 1601, he attended a royal banquet and had to pee…

– …but he held it out of politeness…– …until he died.

• No, really.– His body was exhumed in 2010 and he

was confirmed to have died of a bladder infection after it burst. http://cdn.phys.org/newman/gfx/news/hires/2012/mercurypoiso.jpghttps://fencingclassics.files.wordpress.com/2013/03/tycho2.png

Johannes Kepler (1571-1630)

• Upon Tycho’s death, his data were inherited by his student, Johannes Kepler.

• Kepler is perhaps best known for Kepler’s Laws of Planetary Motion in which he stated the planets have an elliptical orbit (not circular).– We’ll take a close look at these next

lesson.• He also subscribed to the correct

heliocentric model of the solar system.

Johannes Kepler(I’m telling you, those neck things are gonna

come back)

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Johannes_Kepler_1610.jpg/745px-Johannes_Kepler_1610.jpg

Kepler’s Laws

• We’re going to break up this history-fest with a little activity.

• Even though the details of Kepler’s laws will be explored later, let’s take this time to get the basics of elliptical orbit down.– You’ll get some foundational concepts too.

• Ellipse Activity

Key Ellipse Vocabulary

• Eccentricity is the deviation of an ellipse from a perfect circle.

• Major axis is the “long distance” from the ends of an ellipse.

• Semi-major axis is half the major axis.

ZeroEccentricity High Eccentricity

The Climate of the Times

• I’ve left out some important context for all these astronomical advances.

• Historians refer to the time period in which Copernicus, Galileo, and Kepler made their discoveries as…what?– Yep, the Renaissance.

• The Renaissance also sometimes goes by the term, “The Enlightenment,” at least in terms of science.– There were advancements in art and other culture, too.

• It was very much a time of discovery and we can still learn something about the context that birthed such an era.– TED: Steven Johnson – Where Good Ideas Come From

Isaac Newton (1642-1727)

• Known perhaps best for his laws of motion, Newton helped kick-start the field of astrophysics.– In fairness, he had his tentacles in just

about every branch of science at some point in his life.

– We’ll get to those laws next lesson.• For now, Newton’s other

accomplishments include the invention of the reflecting telescope and the publication of Principia, which forever changed the scientific landscape.

http://www.space.com/images/i/000/017/900/original/isaac-newton.jpg?1338316257

Isaac Newton(of Apple fame – get the

pun?)

Aside: Apple Logos• Apple (the company) has an interesting link to

Newton, besides just naming one of their computers after him.

• In reverse order, their logos:

http://3.bp.blogspot.com/-0guh3nL-2sM/UxIa3AXcp6I/AAAAAAAAABg/1IC-boKSH30/s1600/apple-logo-history-012-resized-600.png

Aside: Newton and Hooke

• You might recognize the name of one of Newton’s contemporaries: Robert Hooke.– He was the first to observe cells through a microscope.

• In addition to his biological discoveries, Hooke also spent the end of his life arguing with Newton over which of the two of them first discovered elliptical orbits and the inverse square law.– Oh, I’m sure this is totally unrelated, but when Hooke

died, all known portraits of him were destroyed, so we have no idea what he looked like.

??

Christiaan Huygens (1629-1695)

• Christiaan Huygens (“Hi-you-ghens”) confirmed that Saturn was a ringed planet and also spotted its moon Titan.

• How’d he do that when Galileo could only see blurry “ears” on the planet?– He figured out a way to make a

more precise telescope mirror.http://www.mikroskopie.de/pfad/grundlagen/animationen/huygens.jpg

Christiaan Huygens(with the hairstyle of the time)

Giovanni Cassini (1625-1712)• Cassini used the parallax method to

estimate the distance to Mars.– Others had made somewhat similar

measurements, but mostly with the Moon and Sun, so Cassini is starting to give dimension to the solar system.

– Other discoveries included a more accurate latitude/longitude method that gave a better estimation of the size of France.

• Cassini also discovered four moons of Saturn, a slight gap in the rings of Saturn, and the Great Red Spot on Jupiter.– Guess what? Robert Hooke is co-discoverer

of the Great Red Spot. http://upload.wikimedia.org/wikipedia/commons/d/d6/Giovanni_Cassini.jpg

Giovanni Cassini(hamming it up)

Jupiter

https://solarsystem.nasa.gov/multimedia/gallery/JUP_74HC680.jpg

Cassini-Huygens Spacecraft

• Today, a spacecraft currently exploring Saturn (launched in 1997, has been there since 2004) is named after, well, Cassini and Huygens.– Among its many notable discoveries

is that Enceladus, a moon of Saturn, has an underground ocean of liquid water.

• It also took the photo that will be featured on the first slide of the next lesson.

Moons of Saturn as seen by Cassini-Huygens:

Rhea (front), Titan (rear)

William Herschel (1738-1822)

• Herschel (and his sister Caroline) discovered Uranus.– In fact, Caroline Herschel was the first

woman to discover a comet and ultimately found eight of them.

• He also recorded a ton of new stars/nebulae in his New General Catalogue, which you might recognize for the NGC still used for non-stellar objects.– Today, there are 7840 nebulae and

clusters in the NGC and Herschel discovered 4630 of them.

http://upload.wikimedia.org/wikipedia/commons/3/36/William_Herschel01.jpg

William Herschel(wrong camera, buddy)

http://www.space.com/17432-william-herschel.html

Uranus

https://solarsystem.nasa.gov/multimedia/gallery/uranus_true732X520.jpg

Aside: Discovery of Neptune

• With Kepler’s and Newton’s laws firmly established, in 1781 Anders Johan Lexell computed Uranus’s orbit and found that it didn’t match what it should be, according to Newton’s laws…– …unless there was a massive planet

behind it.• In 1845 Urbain Le Verrier calculated

the likely location of that massive, more distant planet. http://upload.wikimedia.org/wikipedia/commons/f/fa/Lexell.pnghttp://upload.wikimedia.org/wikipedia/commons/8/89/Urbain_Le_Verrier.jpg

Aside: Discovery of Neptune

• Johan Gottfried Galle and his student Heinrich Louis d’Arrest discovered Neptune in under an hour of searching, using Le Verrier’s calculations.– It was the night of September 24, 1846,

and Neptune was less than 1° from its predicted location.• Score one for Newton. That’s a lot of

people standing on a lot of shoulders.http://upload.wikimedia.org/wikipedia/commons/d/da/JohannGalle.jpghttp://upload.wikimedia.org/wikipedia/commons/2/27/Heinrich_Louis_d%27Arrest.jpg

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http://solarsystem.nasa.gov/multimedia/gallery/Neptune_Full.jpg

Edwin Hubble (1889-1953)• Hubble is credited with having

discovered that the universe is expanding.

• He worked with the largest telescopes in the world at the time and used them to discover much about extra-galactic objects (AKA deep space stuff).– You probably know him as the

namesake of the Hubble Space Telescope or the Hubble Deep Field, which is a region containing very young and very distant galaxies. http://www.stsci.edu/~levay/presres/ehubble/jpeg/10_12-19.jpg

Edwin Hubble(not a painting for once)

Closure

• What did all this effort on all those astronomers’ parts get us?– Besides, like, immense knowledge and the

advancement of humanity?• Incredibly beautiful photos like these:

http://alexpetrov.com/memes/astro/deepfield.jpeg

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The Pillars of Creation (Eagle Nebula)

http://www.nasa.gov/sites/default/files/pia08362.jpg Saturn from the Cassini spacecraft

http://www.sun.org/uploads/images/Saturn-cassini-March-27-2004.jpg Saturn from the Cassini spacecraft

If Earth had rings…

• Okay, so these are obviously not actual photos, but if the Earth were to have Saturn’s rings, one artist (Ron Miller) thinks we would see something like this on the horizon…

http://www.black-cat-studios.com/index.html

Washington Capitol

Guatemala

From the Equator (Quito, Ecuador)

Shadow on the Equator at Equinox

Tropic of Cancer at Equinox