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60 Cards in this Set

  • Front
  • Back
Big Bang
about 14 billion years ago, all matter
and energy in the universe was confined to an extremely small area, which
suddenly exploded. The universe has been expanding in size ever since. The age
of the Universe has recently been more accurately determined to be 13.7 ± .1
billion years.
Helium
In the first few seconds of the universe, energy in the form of photons, condensed
out to form the matter of the universe. After a few minutes, the density and
temperature of the universe was such that it fused some of the Hydrogen into
Helium (about 25% by mass).
Milky Way
the home galaxy of our Solar System, and of Earth.

it is 100,000 light years in diameter and 1000 light years in thickness
Early Astronomy
Celestial bodies - the Sun, Moon, planets, and stars -
have provided us a reference for measuring the
passage of time throughout our existence. Ancient
civilizations relied upon the apparent motion of these
bodies through the sky to determine seasons, months,
years, and the hour of day.
First Calenders
The earliest Egyptian calendar was based on the moon's cycles, but later the Egyptians
realized that the "Dog Star" in Canis Major, Sirius, rose next to the sun every 365
days, about when the annual inundation of the Nile began. Based on this knowledge,
they devised a 365-day calendar that seems to have begun in 4236 BC. The Mayans
of Central America relied not only on the Sun and Moon, but also the planet Venus, to
establish 260 day and 365 day calendars.
Obelisk
(slender, tapering, four-sided monuments) were built as early as
3500 BC. Their moving shadows formed a kind of sundial, enabling people to
partition the day into morning and afternoon. Obelisks could also show the year's
longest and shortest days when the shadow at noon was the shortest or longest of the
year.
Shadow Clock
came into use around 1500 B.C. to
measure the passage of hours. This device divided a
sunlit day into 10 parts plus two twilight hours in the
morning and evening. When the long stem with 5
variably spaced marks was oriented east and west in the
morning, an elevated crossbar on the east end cast a
moving shadow over the marks. At noon, the device
was turned around to measure the afternoon hours.
Stonehenge
built over 4000 years ago in England, but
its alignments show its purposes apparently included the determination of seasonal or
celestial events, such as lunar eclipses, solstices and so on.
Zenith
location in the sky, directly overhead
Meridian
imaginary line across the sky, connecting the north celestial pole,
the zenith, and continuing on to the horizon, due south. It splits the sky into an eastern half
and a western half. At local solar noon, the Sun transits your meridian.
North and South Celestial Pole
where the axis of Earth’s rotation meets its surface
Celestial Equator
a line around the Earth, 90 degrees from both poles. The largest circle of rotation of the
Earth.
Ecliptic
defines the path of the Sun among the stars on the Celestial Sphere. It is tilted,
quite naturally, 23.5 degrees compared to the Earth's Celestial Equator

Also defines your Zodiac sign
Asterism
A grouping of stars, like the Big Dipper, that is not
officially a constellation
Circumpolar Stars
a star that, as viewed from a given latitude on Earth, never sets (that is, never disappears below the horizon), due to its proximity to one of the celestial poles.

are therefore visible (from said location) for the entire night on every night of the year (and would be continuously visible throughout the day too, were they not overwhelmed by the Sun's glare
Cause of Seasons
when the Sun lies in the direction of the Summer Solstice, rotation of the
earth will not make the Sun set in the North Pole! Likewise, from the North Pole,
when the Sun is at the Winter Solstice, the Sun will always be below the horizon.
When the Sun is at either of the Equinoxes, The Sun stays right on the horizon.
With a little bit of thought, you can imagine how this affects our view of the Sun from
Cincinnati: at Summer Solstice, the Sun is much higher in the sky during the day and
also stays above the horizon longer.
Equinox
The point(s) on the Celestial Sphere where the Ecliptic and the Earth's Celestial
Equator cross
Solstice
where the Ecliptic and Celestial Equator are farthest apart, making a Winter
and Summer solstice.
Solar Eclipse
When the Moon casts its shadow on the Earth, this occurs.

During a solar eclipse the conical shaped shadow of the moon reaches back toward the earth and
barely reaches to the earth. There are some eclipses where the shadow actually falls short. In either
case, the size of the affected area on the earth directly under the moon's shadow is relatively small.
The maximum size of the moon's shadow on the earth is about 167 miles in diameter and it travels at
a minimum of 1,100 miles per hour. The shadow is typically smaller and usually moves faster than
that. It is only inside of this racing shadow that you will experience a total solar eclipse as the
moon's disk completely covers the sun's disk. Total solar eclipses are notoriously short, only a few
minutes long.
Lunar Eclipse
When the Earth casts its shadow on the Moon, this occurs

During a lunar eclipse, the moon, on its orbit passes through the shadow of the earth. Since the earth
is so much larger than the moon, the earth's shadow is larger and longer. It is more than a million
miles long, and, at the distance of the moon, is several times larger than the moon. Unlike a solar
eclipse where the small shadow passes over your location in just a few moments, it can take the
moon several hours to pass through the shadow of the earth. Lunar eclipses are much longer than solar eclipses.
Umbra
The region of the
shadow inside of which totality is experienced is called the umbra. No part of the sun is visible from
within the umbra. The umbra is cone-shaped and projects directly away from the sun diminishing in
diameter as you move away from the shadow casting body.
Penumbra
Around the umbra and antumbra is a region where the body only partially obscures the sun,
this region is called the penumbra and like the antumbra it is an expanding cone, but it originates
from the body itself.
Antrumbra
If you proceed past the tip of the umbrayou will enter another cone, this one increasing in diameter with distance, called the antumbra.
From within the antumbra, you would see the sun as a round disk larger than the body casting the
shadow.
Total Solar Eclipse
The umbra's footprint on the earth is very small and one must be directly under the
shadow to experience a total solar eclipse.
Partial Solar Eclipse
If you are within several hundred miles of the path of the
shadow you will experience a partial solar eclipse as from your point of view, the moon's disk
grazes past the sun only partially covering it.
Annular Solar Eclipse
f the moon is near apogee, its distance from the earth
will be farther than the length of the umbra, so the antumbra moves across the earth's surface. From
within the antumbra the disk of the moon is smaller than the disk of the sun and it cannot cover it
completely. It leaves the disk of the sun as a ring around the smaller disk of the moon. This is
called an annular solar eclipse derived from the Greek word annulus, meaning ring or circle.
Photosphere
Surface of the sun
Chromosphere
a thin layer of the Sun's atmosphere just above the photosphere, roughly 2,000 kilometers deep.
Corona
Extended outer atmosphere of the sun
Eclipse Year
The nodes of the lunar orbit are gradually shifting their orientation in
space, giving us proper alignment about every 346.6 days
Ofteness of Eclipses
Since the eclipse year is shorter than the tropical year, it is possible to have the tropical year begin
with an eclipse season, experience a second eclipse season about 155 days later, and end the year
with part of a third eclipse season. This only happens once every couple of decades and provides the
opportunity for as many as 7 eclipses in 1 tropical year. Typically there are two eclipse seasons per
tropical year and typically each eclipse season contains two eclipses. So usually there are only 4
eclipses a year, 2 solar and 2 lunar, but precise phasing of the tropical year, the eclipse year and the moon's nodes, 5 or 6 or (very rarely) 7 eclipses can occur in 1 tropical year
Nodes
the two points where the Moon's orbit intersects the plane of the Earth's orbit, the
ecliptic
Why does the moon turn red during a lunar eclipse
Some of the Sun's light passes through Earth's
atmosphere and is bent around and behind the
Earth. Much of this light is scattered as blue
light, and never reaches the lunar surface.
Only the longer wavelengths of light (mostly
red or orange) will reach the Moon, tinting its
surface in a coppery glow.
Penumbral Lunar Eclipse
Sometimes the moon only enters the penumbra without
touching the umbra.
arc second
: a sub-division of an arc-minute (1/21,600th of a circle) into 60 equal finer divisions. Equal to 1/60th of an arc-minute, 1/3,600th of a degree, or 1/1,296,000th of a complete circle. It is symbolized by a double accent or quote following the value, as in 8” (eight seconds). It is an angular measurement and not related to any unit of time.
arc minute
a sub-division of a degree (1/360th of a circle) into 60 equal finer divisions. Equal to 1/60th of a degree, or 1/21,600th of a complete circle. It is symbolized by a single accent or quote following the value, as in 31’ (thirty-one minutes). It is an angular measurement and not related to any unit of time.
angular size of the moon
29.3′ to 34.1′
Why were Aristotle's astronomical theories so detrimental to the progress of
western astronomy?
His
astronomical views were biased towards absolute
symmetry, simplicity and perfection. Aristotle, proposed
models where the stars, Sun, Moon, and planets are
attached to spherical transparent shells undergoing
uniform circular motion around the Earth. This is
known as a Geocentric Universe.
Parallex
Stellar parallax occurs as the Earth orbits the Sun and our line of sight to a nearby
star varies. The effect is to make the star appear to shift position over the course of
the year. In reality, stellar distances are so great that parallax shifts are less than an
arc second, completely unobservable to the unaided eye.
Parallex continued
1. The Earth is not part of the heavens.
2. The celestial objects are bright points of light while the Earth is an immense
non-luminous sphere of mud and rock.
3. There is little change in the heavens: Stars are the same night after night. Earth
is home of birth, change, and destruction. Celestial bodies have immutable
regularity that is never to be achieved on the corruptible Earth.
4. Our senses show Earth is stationary: Air, clouds, birds, and other things
unattached to Earth are not left behind, as they would be if the Earth were moving.
There is no strong wind. If the Earth were moving, then a man jumping from a
high point would hit the Earth far behind from the point where the le
Heliocentric
Sun centered Universe
Ptolemaic model for Planetary Motions
Ptolemy attempted to explain the backwards motion in the sky by placing the planets on a small circular path that was not quite centered on a larger circular path. Offset circles on circles:
Epicycles
A small circle whose center moves around the circumference of a larger one.
retrograde motion
The motion in question is called retrograde motion and it occurs when a particular planet, "wandering" eastward along the ecliptic for the most part, slows down, stops and then moves westward for a while. It soon (several weeks later) slows down, stops moving westward, and begins moving eastward again.
-This temporary, apparent, "backwards" motion against the Celestial Sphere is caused by the Earth orbiting the Sun faster than the planets that are farther from the Sun.
-all the planets farther away from the earth have retrograde motion. They are called superior planets.
After the fall of the roman empire
IX-XI century A.D. Intensive development of Arabic and Persian astronomy (star
charts and catalogs, planets and the Moon movement, better estimations of the
Earth size, and calendar improvement)
A.D. 813 Al Mamon founds the Baghdad school of astronomy. Mathematike
Syntaxis by Ptolemy is translated into Arabic as al-Majisti (Great Work) later
called by Latin scholars Almagest
A.D. 903 Al-Sufi draws up his star catalog
1054 Chinese astronomers observe supernova in Taurus (now this supernova
remnant is known as the Crab Nebula (M1)
Why did Copernicus's heliocentric model 'fail'? What is the significance of
'The Revolution'?
Recall the premise for the Ptolemaic Model: 1) Earth-Centered, 2) Uniform
circular motion. BOTH are wrong and the Copernican model only corrected the
first error. In this way, the Copernican model had both radical and conservative
aspects

By the 15th century exploration of new trade routes via sea-going ships begins in
earnest. New navigation technologies are needed (based on astronomical
knowledge). The Catholic Church's power begins to erode. People begin asking
for a new way of worship. The Protestant Reformation!
Brahe
Danish, From his underground observatory, Uraniborg, he studied and measured the heavens for more than 20 years. He compiled detailed observation logs of the locations of the stars, planets and comets, all before the invention of the telescope. He never processed any of the data and hired Johannes Kepler to analyze the data and provea Brahe-based Ptolemaic hybrid model of the Universe correct a year before Brahe’s death

He believed in a geocentric universe

He discovered a new distant star in Cassiopeia
Kepler
Used Copernicus observations and Brahes data to develop his three laws
Keplers three laws
1. The orbit of every planet is an ellipse with the Sun at one of the two foci

2. A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.[1]

3. The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
-third equation uses p as orbital period, a as the semi major axis in oribt, m as mass and g as gravitational constant.

I think Galileo would later know why these laws existed.
Galileo FIVE observational discoveries
1. Craters on the Moon

2. The milky way was made of stars

3. Moons of Jupiter

4.Sunspots

5.The phases of Venus
Craters on the Moon
He reported that the moon was not perfect, but instead
had deep shadows from valleys and mountains on its
surface. He also showed it was a world not unlike Earth.
The milky way was made of stars
He showed that the great "cloud" called the
Milky Way (which we now know to be the
disk of our spiral galaxy) was composed of
enormous numbers of stars that had not
been seen before.
Moons of Jupiter
Galileo observed 4 points of light that changed their positions with time around the
planet Jupiter. He concluded that these were objects in orbit around Jupiter. Io,
Europa, Ganymede, and Callisto are shown below with approximately the correct
scale of their orbit and motion to the size of Jupiter's disk.

These observations showed there were new things in the heavens that Aristotle and
Ptolemy had known nothing about. Jupiter's moons demonstrated that a planet
could have moons circling it (other centers of motion) that would not be left behind
as the planet moved around its orbit!
Sunspots
Galileo saw that the Sun had dark patches on it,
sunspots. Furthermore, he observed motion of the
sunspots indicating that the Sun was rotating.
"Blemishes" on the Sun were contrary to the doctrine
of an unchanging perfect substance in the heavens, and
the rotation of the Sun made it less strange that the
Earth might rotate on an axis too, as required in the
Copernican model.
The phases of Venus
Galileo used his telescope to show that Venus went through a complete set of
phases, just like the Moon. This observation was among the most important in
human history, for it provided the first conclusive observational proof that was
consistent with the Copernican system but not the Ptolemaic system. This was
because the two systems make different predictions for the progression of the
phases of Venus (see below)
These discoveries were made from 1608 to 1612, making him quite famous AND
at the center of controversy with the Catholic Church. By 1616, Galileo was
formally requested by the Church to cease debating (teaching or publishing) his
scientific results that supported the Copernican model. From 1616 until around
1630, Galileo did hold off from working on Astronomy. However, he returned to
his astronomical research later in life, which eventually got him into deep trouble
with the Inquisition. At age 70, he was forced to recant the Copernican system
and spent the rest of his natural life under house arrest at his villa.
Newton discoveries
Newton invented calculus and designed the first reflecting telescope (called a
Newtonian design!) based on his studies of light. For the purposes of this class, we
shall limit ourselves to his discoveries in Mechanics, specifically having to do
with motion and gravitation. In particular, Newton thought like no one previous to
him: Analytically seeing the Universe's motions and recognizing that there existed
a force, a natural influence existing between particles that affected these motions.
Newtons THREE laws
I. Every object in a state of uniform motion tends to remain in that state of
motion unless an external force is applied to it.

II. The relationship between an object's mass m, its acceleration a, and the
applied force F is F = ma. In this law the direction of the force is the same as
the direction of the acceleration

III. For every action there is an equal and opposite reaction.
Bodes Law
The law relates the mean
distances of the planets from the sun to a simple mathematic progression of
numbers.

Doesnt work for all planets

I think Newton is science not Bode
Clavius
German, Jesuit Vatican astronomer to Pope Gregory XIII, who calculated a more correct value for the length of the tropical year. He provided the leap year cycle pattern to keep the civil year (integer solar days) and the tropical (seasonal) year in synch, what we call today the Gregorian Calendar. Wednesday October 4 1582 was followed by Thursday October 15 1582 to account for the extra days that had been added in since Julius Caesar introduced the simple 4-year pattern of leap years 1600 years earlier. Also created decimal and vernier scale
Harrison
Carpenter, clockmaker and inventor of the Marine Chronometer and solver of the "Longitude Problem". He is responsible for modern accurate timekeeping and made it possible for ships to accurately calculate their positions on the open sea. He is credited with inventing jewel bearings, roller bearings, bi-metallic strips for temperature compensation, the grasshopper escapement and the gridiron pendulum.