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Astronomy 121 first 8 lectures


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the main purpose of science is based on the philosophy of...
rationalism- conforming with reason
Those who pursue answers are known as...
The main occupation of a scientist is...
problem solving
Four forms of scientific arguments...
1) deduction 2) induction 3) probability 4) statistics
Math and computer simulations...logic/rational thought...laws of nature
temporal data...correlations/patterns...rules of nature
temporal data...likelihood...generalities of nature
sets of data...trends... predictions of nature
4 steps of scientific method
Science is separated from pseudo-science by...
the principle of falsification
the idea that events are related by a chain of causation (cause and effect)
3 components of cause and effect
1) contiguity in space
2) temporal priority of the cause (it comes first)
3)necessary or energy connection
the belief that any complex set of phenomena can be defined or explained in terms of a relatively few simple or primitive ones
astronomy involves what other sciences...
pysics, math, chemistry, geology, and computer science
astronomy asks what basic question
how does the universe operate?
astronomy is the study of..
all things above the earth's atmosphere
360 degrees is how many pi
2 pi
what is 10 to the 3
what is 10 to the -3
distance equals...
velocity x time
an Angstrom is
10 to the -8 cm
an Astronomical unit is
1.496 x 10 to the 8 km
Which of the following is not a form of problem solving?
balancing your checkbook, doing a puzzle, measuring your height, searching for keys, deciding on a plate at a restaurant
measuring your height
Sherlock Holmes says he uses dedcution but he actually used induction because...
a) he shared them with Watson
b) he draws conclusions from evidence
c) he uses only pure logic
d) he used them to control the unpredictable
e) all o
b) he draws conclusions from evidence
) Pseudo-science can be recognized because

a) it is not true
b) it is clearly false
c) it can not be proven to be true
d) it can not be falsified
e) b and c
d) it can not be falsified
4) How many Ϭ's is 90 degrees?

a) 1/4
b) 1/2
c) 1
d) 2
e) 4
b) 1/2
5) A planet has an angular size of 20 degrees. If the planet moves twice the distance away, its angular size will be

a) 5 degrees
b) 10 degrees
c) 20 degrees
d) 40 degrees
e) can not determine from information given
b) 10 degrees
6) If planet A has an angular size of Ϭ/8 and planet B has an angular size of Ϭ/4, which planet is larger in physical size?

a) A
b) B
c) they are both the same size
d) can not determine from information given
d) can not determine from information given
7) What is 10 to the 5 times 10 to the 9

a) 10 to the 4
b) 10to the5
c) 10to the9
d) 10to the14
e) 10to the-4
d) 10 to the 14
8) What is 10 to the -19 divided by 10 to the -4?

a) 10 to the 4
b) 10 to the 19
c) 10to the 23
d) 10 to the -23
e) 10to the -15
e) 10 to the -15
9) What is 10 to the 3.5 times 10 to the -4 divided by 10 to the 2.5?

a) 10 to the -1.5
b) 10 to the +1.5
c) 10 to the +7.5
d) 10to the -3
e) 10 to the -6
10 to the -3
what is the distance from the sun to the earth
1.496 x 10 to the 8 km
the earliest written records were...
astromical observations
Stonehenge is
a big computer for calulating the position of the planets and the Sun
Thales used data from the Babylonians to
predict eclipses
Eratosthenes used the shadow of the earth on the moon during an eclipse to measure...
the circumference of the earth
Hipparchus recorded the names of _______ in the first star catalogue
Heraclides formed the first Solar System model which was...
geocentric meaning the earth was in the middle (and the orbits were perfect circles)
Aristarchus developed solar system model which was
heliocentric meaning the Sun was in the middle
3 problems for the heliocentric model were
1)if the earth is in motion why can't we feel it
2) no parallax seen in stars
3) geocentric- ego-centric- more natural
Ptolemy added on to the geocentric model and used a system of circles on circles to explain...
retrograde motion and the orbits of the planets
During the Renaissance, Copernicus recreated the heliocentric theory but had to use more complex circles so...
it failed and was not accepted
Tycho Brahe built the Danish Observatory using _____ instead of telescopes (since they had not been invented yet)
Kepler corrects the problems of epicycles in the heliocentric theory by using _______ instead of circles for orbits of the planets.
With his 3-inch telescope, Galileo found what 5 discoveries that destroyed the idea of a perfect universe?
1) spots on the Sun
2) mountains and "seas" (maria) on the Moon
3) Milky Way is made of lots of stars
4) Venus has phases
5) Jupiter has moons
Who developed the Law of Universal Gravitation, laws of accelerated motion, invented calculus (math tool), the 1st reflecting telescope and theory of light?
1) The Apolo astronauts could have performed Eatosthenes experiment on the Moon. Apollo 11 landed on 20 July 1969 in Mare tranquillitatis, on the Moon's equator. The last lunar mission, Apollo 17 on 11 Dec 1972, landed at Taurus-Littrow at latitude +20 d
c) 10,908 km
2) What is the radius of the Moon compared to the Earth?

a) 0.10
b) 0.17
c) 0.27
d) 0.98
e) 1.54
c) 0.27
5) How many planets were visible to Greek astronomers (not the Sun and Moon, only planets)?

a) 4
b) 5
c) 7
d) 9
e) they could see any planets
b) 5
6) How many times a year, at most, will Mars display retrograde motion

a) once
b) twice
c) three times
d) at least five
e) cannot determine from information given
a) once
7) The flatter an ellipse, the

a) higher its eccentricity
b) greater the distance between focus points
c) larger the ratio of major to minor axis
d) the major axis is longer than the minor axis
e) all of the above
e) all of the above
8) The light gathering power of a telescope goes as the square of the diameter of the lens. If the human eye is 0.5 inches across and Galileo's telescope was 3 inches across, how much more powerful was Galileo's telescope compared to the human eye?
d) 36 times more powerful
9) Tycho achieved a new level of accuarcy at the time by measuring the position of planets to an arcminute. An arcminute is 1/60 of a degree. If Tycho found that Mars moved 30 arcmins per day, how long for Mars to go around the sky (its year)?

c) 720 days
The shortest path between two points on the surface of a sphere is given by ____________ passing through the two points
the arc of a great circle
the intersection with a sphere of a plane containing the center of the sphere is a __________
great circle
If the plane does not contain the center of the sphere, its intersection with the sphere is known as a ___________
small circle
a triangle drawn on the surface of a sphere is only a spherical triangle if it has all of the following properties:
The three sides are all arcs of great circles.
Any two sides are together greater than the third side.
The sum of the three angles is greater than 180°.
Each spherical angle is less than 180°.
Great circles which pass through the two poles are known as ________
small circles which lie parallel to the equator are known as ________ or __________
parallels or latitude lines
the point directly over head is the _________
______ is defined as the angle between the vertical through the north point and the vertical through the star at X,
The sky and area around you when you are outside is the __________
celstial sphere
The ________ of a ________ is its angular distance in degrees measured from the celestial equator along the meridian through the star
The declination of a star
Drawn onto the celestial sphere are imaginary shapes called
constellations- Latin for 'group of stars'
How many constellations are there?
Hipparchus also developed a simply method of identifying the stars in the sky by using a letter from the ________ __________combined with the constellation name
Greek alphabet
About _______ stars are visible with the naked eye on a dark, moonless night. However, there are over _____ stars in the whole Milky Way galaxy were the solar system resides
6,000 / 10 to the 13
The 12 of the 88 constellations that the sun's circle passes through is the
The point were the Sun is highest in the northern hemisphere is called the _______ ________. The lowest point is the ________ _______.
summer solstice / winter solstice
The _______ are caused by the angle the sun's rays make with the ground
A _____ is defined by one rotation of the object in question
A _____ is defined by one revolution of the object in question
Typical we use _______ time, which means with respect to the Sun
As the Moon moves counterclockwise around the Earth, the daylight side becomes more and more visible meaning the moon is
After full Moon is reached we begin to see more and more of the nighttime side meaning the moon is
On rare occasions the Moon comes between the Earth and the Sun (a _________)
solar eclipse
When the Moon enters the Earth's shadow...
a lunar eclipse
eclipses happen __ to ___ times a year
2 to 5
all solar eclipses happen at ______ and last only _________
new moon / 4 to 7 minutes
All lunar eclipses occur at ________
full moon
1) You live in Eugene, OR at longitude 123W and latitude 44N. On the summer solstice, at high noon, what is the angle of the Sun from the horizon? (Making a diagram of the sky marking the NCP, zenith, celestial equator and ecliptic will help you solve th
c) 69.5 degrees
2) On the winter solstice, at high noon, what is the angle of the Sun from the horizon?

a) 22.5 degrees
b) 44 degrees
c) 88.5 degrees
d) 90 degrees
e) 110 degrees
a) 22.5 degrees
3) Which of the following is not a great circle?

a) latitude 0N parallel
b) latitude 45N parallel
c) longitude 0E meridian
d) longitude 110E meridian
e) the equator
b) latitude 45N parallel
5) A star has a declination of 60N degrees, how many degrees is it from the north celestial pole?

a) 10
b) 20
c) 30
d) 40
e) 60
c) 30
6) You live at 30N latitude. How far is the North Star from the zenith?

a) 10 degrees
b) 20 degrees
c) 30 degrees
d) 60 degrees
e) 90 degrees
d) 60 degrees
7) Circumpolar stars are those stars which never set below the horizon due to their close angular distance to the north celestial pole. As you travel north, are their fewer or more circumpolar stars?

a) fewer
b) more
c) the same amou
b) more
8) Where on the Earth's surface can you view all the constellations throughout the year?

a) north pole
b) south pole
c) equator
d) 45 latitude
e) there is no place on the Earth
c) equator
9) You see the Moon, half illuminated on the left side, on the meridian. The time is

a) midnight
b) 3 am
c) 6 am
d) noon
e) 3 pm
c) 6am
10) If you see the Moon in early afternoon, then it is

a) new
b) full
c) waxing
d) waning
e) it can be any of the above
c) waxing
The planets outside of the Earht's orbit are called ______ planets and they are
superior / Mars, Jupiter, Saturn, Uranus, Neptune
The planets inside the Earth's orbit are ______ planets and they are
inferiour/ Mercury, venus
passage of an inferior planet across the Sun is called
Galileo invented the laws of _____
the cause of motion is....
the resistance to change in motion is called...
the natural state of motion for an object is
rest or uniform motion
1st law (law of elliptic orbits) is
Each planet moves in an elliptical orbit
2nd law (law of equal areas) is
a line connection the Sun and a planet (called the radius vector) sweeps out equal areas in equal times--Objects travel fastest at the low point of their orbit, and travel slowest at the high point of their orbit.
3rd law (law of harmonics) is
The square of a planet's orbital period is proportional to its mean distance from the Sun cubed.
P2 = R3
the period, P,
the radius, R
only _____ planets have phases
For a ______ orbit, the velocity sufficient to escape gravitation pull of the planet
the _______ is the amount of kinetic energy acquired by the rocket at burnout (it also determines the orbit type)
burnout velocity
this type of orbit is used for satellites for spy use or weather- the earth turns under them once per day (total coverage)
polar orbit
these orbits are used for communication satellites because they have continuous coverage of one region of the globe
geosynchrous orbits
1) Venus' greatest western elongation is 45 degrees. This means that Mercury's greatest eastern elongation must be

a) greater than 45 degrees
b) less than 45 degrees
c) equal to 45 degrees
d) can be any value depending on time o
b) less than 45 degrees
2) According to Galileo, a ball rolling on a flat desert would roll forever. But we know that a ball rolling on the ground eventually comes to a stop due to friction. Where does all the energy of motion go?

a) it disappears
b) it is store
d) it is turned into heat
3) According to Kepler's 2nd law, a satellite in a highly eccentric orbit will move the fastest at

a) aphelion
b) perihelion
c) midpoint
d) it always travels at the same speed
e) impossible to determine
b) perihelion
4) Again, according to Kepler's 2nd law, to make your orbit smaller you need to go

a) faster
b) slower
a) faster
5) Using Kepler's 3rd law, a new planet (called X) has a roughly circular orbit with a radius 1.5 times the Earth's orbital radius. Therefore, its `year' or orbital period is

a) shorter than the Earth's
b) the same as the Earth's
c) greater than the Earth's
6) If planet X had an orbital period of less than 365 days, then we know it is located

a) beyond Mars
b) beyond the Earth's orbit
c) inside the Earth's orbit
d) inside Mercury's orbit
e) it could be anywhere
c) inside the Earth's orbit
7) If the orbital period of planet X is 2 years, then its semi-major axis is

a) 0.89 A.U's
b) 0.99 A.U's
c) 1.59 A.U's
d) 2.82 A.U's
e) 5.00 A.U's
c) 1.59 A.U's
8) If the semi-major axis of planet X is 0.5 A.U's, what is its orbital period?

a) 0.10 years
b) 0.35 years
c) 1.10 years
d) 3.44 years
e) 10.1 years
b) 0.35 years
9) To send a probe to Mercury do you need more or less velocity than to go to Mars?

a) more
b) less
c) the same
a) more
10) If you wanted to make a continuous map of the Earth's oceans, you would use a

a) geosynchronous orbit
b) equatorial orbit
c) polar orbit
d) hyperbolic orbit
e) all of the above
c) polar orbit
the time rate at which velocity is changing
acceleration (caused by force)
resistance to change in velocity (proportional to the mass of the object)
ratio of inertia
mass1 x acceleration1 =
mass2 x acceleration2
M1/M2 = A2/A1
quantity of motion energy and is equal to mass times velocity
law of conservation of momentum
total momentum (mass x velocity) of an interaction is conserved -> is the same before and after
concept that states that the total momentum of the Universe is conserved, interactions redistribute the momentum, but the total never changes
clockwork universe
Newton's laws of motion (1-3)
1st law: a body remains at rest or moves in a straight line of constant velocity as long as no external forces acts on it

2nd law: a body acted on by a force will accelerate such that force equals mass times acceleration (F=ma)
3rd law: for every action there is an equal and opposite reaction
planets travel in orbits around the sun instead of straight lines because of ______
Newton's Law of Universal Gravitation
F=(G x m1 x m2)/ R to the 2

F- force of gravity
G- gravitational constant
m1- mass of object 1
m2- mass of object 2
R- distance b/t objects
gravitational constant
6.668 x 10 to the -8 dynes cm 3 g -2
the three body problem- because of ________ ______
the equations of orbits could be solved for two bodies, but could not be solved for three or more bodies- deterministic chaos
water tides are caused by these 3 factors
1) location on the Earth's surface
2)orientation of the Sun and the Moon (both has approximately equal tidal influence on the surface of Earth)
3)geographic features (shape of bay, inlets, etc.)
when the tidal forces become greater than the internal gravity of an object and The object is torn apart at the
Roche Limit
1) If a baseball masses 10 times more than a ping-pong ball, how much more will the ping-pong ball accelerate from the swing of the same bat?

a) the same acceleration
b) 5 times more
c) 10 times more
d) 20 times more
e) ca
c) 10 times more
2) Which has more momentum, a 5,000 lbs truck moving at 20 mph or a 100 lbs cyclist moving at 50 mph?

a) the truck
b) the cyclist
c) they both have the same amount of momentum
d) cannot determine from information given
a) truck
3) If a 10,000 lbs truck moving at 20 mph strikes a 2,000 lbs car at rest, and all the momentum is transfered to the car, how fast will the car be moving afterwards?

a) 10 mph
b) 20 mph
c) 50 mph
d) 100 mph
e) 200 mph
d) 100 mph
4) In the same situation above, if only 1/2 the momentum is transfered, how fast is the car moving afterwards?

a) 10
b) 20 mph
c) 50 mph
d) 100 mph
e) 200 mph
c) 50 mph
5) In the same situation above, if only 1/2 the momentum is transfered, how fast is the truck moving afterwards?

a) 10 mph
b) 20 mph
c) 50 mph
d) 100 mph
e) 200 mph
a) 10 mph
6) The Moon is about 1/4 the radius of the Earth, and 1/80 its mass. What is the surface gravity of the Moon, compared to the Earth, with these values?

a) 1/10
b) 1/6
c) 1/5
d) 1/2
e) the same
c) 1/5
7) How does the force of gravity compare for a 150 lbs astronaut on the Earth's surface to the same astronaut in a 200 km orbit?

a) much more
b) pretty much the same
c) much less
d) there is zero gravity in outer space
b) pretty much the same
8) How do we know there is not a Moon-sized, invisible object orbiting near the Earth

a) Newton's 1st law
b) Kepler's 2nd law
c) tides
d) Roche limit
e) perturbations on Uranus
c) tides
9) Is the Moon inside or outside the Roche limit?

a) outside
b) inside
c) right at the edge
a) outside
10) The most important result from deterministic chaos is

a) the laws of Nature are deterministic
b) Nature is random
c) there is no free will
d) simple rules can produce considerable complexity
d) simple rules can produce considerable complexity
Roemer was the first to measure the speed of light using
Jupiter's moons
Maxwell showed that light is energy carried in the form of opposite but supporting electric and magnetic fields in the shape of ________
short wavelengths are high energy (2)
gamma rays and x-rays
long wavelengths are
radio waves
The whole range of wavelengths is called the _______________ _____________.
electromagnetic spectrum
our eyes only see the ________ spectrum with wavelengths between _____ and _____ nm
visible/ 400, 700
out atmosphere is _____ to certain wavelengths meaning they can only be observed from space
three properties of light when encountering a medium
angle of incidence is equal to the angle of _______ and greater than the angle of -_____
reflection, refraction
_________ is the constructive and destructive interference of two beams of light that results in a wave-like pattern
inverse square law (brightness)
brightness = 1/d to the 2

doppler effect- speed of light does not change- only the wavelength- moving towards the observer = _________ or _________ / moving away from the observer ________ or ________
compressed, blueshifted/ expanded, redshifted
energry output =
temperature to the 4
peak wavelength =
a solid or liquid body radiates an uninterrupted, smooth spectrum (Planck curve)
continuous spectrum
a radiating gas produces a spectrum of discrete spectral lines
emission spectrum
a continuous spectrum that passes through a cool gas has specific spectral lines removed (inverse of an emission spectrum)
absorption spectrum
1) Gamma rays are about (watch the units and do some conversion work)

a) 10-5 mm
b) 10-7 mm
c) 10-10 mm
d) 10-12 mm
e) 10-16 mm
c) 10 to the -10 mm
2) A human being is the size of what kind of light?

a) gamma rays
b) UV
c) visible
d) microwave
e) radio
e) radio
3) Is a light of wavelength 10-4 meters blocked by the atmosphere?

a) yes
b) no
c) can't tell
a) yes
4) If the angle of incidence is 30 degrees, the angle of reflection is

a) 10 degrees
b) 30 degrees
c) 50 degrees
b)30 degrees
5) From air to oil, if the angle of incidence is 30 degrees, the angle of refraction is

a) less than 30 degrees
b) equal to 30 degrees
c) great than 30 degrees
d) cannot determine from information given
a) less than 30 degrees
6) Mars is about 2.5 A.U.'s from the Sun. High noon on Mars is about

a) 1/100 as bright as Earth
b) 1/6 as bright as Earth
c) 1/2 as bright as Earth
d) twice as bright as Earth
e) 100 times as bright as Earth
b) 1/6 as bright as Earth
7) If you double the temperature of a body, how much more energy does it radiate?

a) the same amount
b) twice as much
c) 4 times as much
d) 8 times as much
e) 16 times as much
e) 16 times as much
8) Humans emit most of their energy in the near-IR (about 10 microns). How much would we have to increase your temperature so that you glowed blue?

a) twice as much
b) 10 times as much
c) 25 times as much
d) 100 times as much
c) 25 times as much
9) A star goes from 3,000K to 9,000K. How much more energy does it emit?

a) the same amount
b) 1/2 as much
c) 6 times more
d) 9 times more
e) 81 times more
e) 81 times more
10) A neon light produces what kind of spectrum?

a) continuous spectrum
b) absorption spectrum
c) emission spectrum
d) no spectrum
c) emission spectrum
He hypothesized that all matter is composed of tiny indestructible units, called atoms
And that the typical diameters of an atom is
10 to the -8 cm
four states of matter
solid, liquid, gas, plasma
bonds of atoms in a solid
bonds of atoms in a liquid
bonds of atoms in a gas
bonds of atoms in plasma
The change from one state of matter to another is called a
phase transition.
the hotter the temperature the ______ the atoms move
__________ is explained as the momentum transfer of those moving atoms on the walls of the container (faster atoms = higher temperature = more momentum/hits = higher ________
John Thomson used a _______ _____ _______, Thomson determined that all matter, whatever its source, contains particles of the same kind that are much less massive than the atoms of which they form a part
cathode ray scope
Thompson's Atom
positively charged "pudding" with negatively charged
"plums" in it
the father of nuclear physics
Ernest Rutherford
Rutherfords gold foil experiment demonstrated that that the atom has a
when nuclei spontaneously split into smaller nuclei and emit stray particles
the mass of the electron is ________ the mass of the proton
the mass of the proton equals the mass of the
The amount of energy emitted from stars is determined by measuring their ________, this is called ___________
brightness/ photometry
a device that separates white light into component colors called a spectrum.
the invention of the sprectroscope and the discovery that elements emit a unique sprectrum allowed astronomers to measure the ________ ________ of stars
chemical composition
Fraunhofer discovered _______ ______ which could be identified with particular elements
spectra lines
Lockyer discovered an unknown element in the Sun which he named
energy, at the subatomic level, can only be transferred in small units called ______
The term _______ _____refers to the abrupt movement from one discrete energy level to another, with no smooth transition
quantum leap
The Bohr model atom has
orbits for the electrons
The power in the Bohr model was its ability to predict the ________ of light emitted by atoms
The planets in order of their distance from the sun
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Kuiper Belt objects (e.g. Pluto
the planets and asteroids revolve around the Sun in the same direction ___________
The Sun contains ______ of all the matter in the Solar System
Jupiter contains more than _____ the matter of all the other planets combined.
The four _________ worlds are the innermost planets in the solar system, Mercury, Venus, Earth and Mars
primary terrestrial
8 other terrestrial worlds
the Moon, Io, Europa, Ganymede, Callisto (the four Galilean moons), Titan (a moon of Saturn), Triton (a moon of Neptune) and Pluto
planets that have they have a compact, rocky surface like the Earth's and are spherical in shape are called ________
Jupiter, Saturn, Uranus, and Neptune are known as the
Jovian (Jupiter-like) planets
planets that are similar in size and structure, i.e. gigantic compared with Earth and having a non-solid, gaseous nature are called _______
a ______ or ______ revolves around a planet instead of the sun
moon or satellite
periods of rotation are determined by... (4)
timing surface features
timing clouds and atmospheric features
reflected sunlight (light curves)
Doppler radar measurements of planet limb
information about temperature and surface features is obtained by
information about chemical compositions is obtained by
information about surface topology is obtained by
radar mapping
information to analyze, survey, sample, and magnetic fields
space probes
any model of the solar system formation must explain the following facts (4)
1) All the orbits of the planets are prograde (i.e. if seen from above the North pole of the Sun they all revolve in a counter-clockwise direction).
2) All the planets have orbital planes that are inclined by less than 6 degrees with respect to each other (i.e. all in the same plane).
3) All the planets have low eccentricities.
4) All planets have prograde rotation except Venus and Uranus.
common gaseous materials found in solar system (and temp)
hydrogen, helium, neon / 10K
common icy materials in the solar system (and temp)
water, methane, ammonia, carbon dioxide / 100K
common rocky materials in the solar system (and temp)
iron, iron sulfide, olibine, pyroxene 5000K

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