In This Lesson:
Unit 2
The History of
Astronomy
(Lesson 1 of 2)
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/wpcontent/uploads/2013/05/mauna-kea-2.jpg
Mauna Kea Observatories, HI
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 300800 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.
Hans Lippershey
http://micro.magnet.fsu.edu/optics/timeline/people/lippershey.html
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.
Aristarchus of Samos
(ahead of his time)
– You heard me right.
– Aristarchus had the “Sun at
the center” thing in mind a
long time ago.
http://www.hudsonvalleyalmanacweekly.com/wpcontent/uploads/2012/07/ARISTARCHUS-@.jpg
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.
Ptolemy
– The catch? The Catholic Church kinda (tellin’ you not to do that)
got attached to the whole geocentric
thing.
http://upload.wikimedia.org/wikipedia/commons/0/0b/
– Fan, prepare to meet S---.
PSM_V78_D326_Ptolemy.png
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 “Tieco 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.
https://fencingclassics.files.wordpress.com/2013/03/tycho2.png
http://cdn.phys.org/newman/gfx/news/hires/2012/mercurypoiso.jpg
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.
Zero
Eccentricity
High Eccentricity
• Major axis is the “long distance” from the
ends of an ellipse.
• Semi-major axis is half the major axis.
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-youghens”) 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 codiscoverer of the Great Red Spot.
Giovanni Cassini
(hamming it up)
http://upload.wikimedia.org/wikipedia/commons/d/d6/Giovanni_Cassini.jpg
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/8/89/Urbain_Le_Verrier.jpg http://upload.wikimedia.org/wikipedia/commons/f/fa/Lexell.png
– 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.jpg http://upload.wikimedia.org/wikipedia/commons/2/27/Heinrich_Louis_d%27Arrest.jpg
Heinrich Louis d’Arrest
• Johan Gottfried Galle and his student
Heinrich Louis d’Arrest discovered
Neptune in under an hour of
searching, using Le Verrier’s
calculations.
Johan Gottfried Galle
Aside: Discovery of Neptune
Neptune
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
Edwin Hubble
namesake of the Hubble Space
(not a painting for once)
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
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
The Pillars of Creation (Eagle Nebula)
http://alexpetrov.com/memes/astro/deepfield.jpeg
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