final exam unit 1-2
the sun usually rises in the
east
Because the Earth goes around the Sun, we see the Sun move
eastward along the ecliptic
When Copernicus published his final version of the Copernican System in 1543, it was
rejected by most astronomers as not really any better than the Ptolemaic System.
The idea that science only deals with statements that are falsifiable, subject to possible disproof by observation, suggests that
science produces revisable facts
As seen from North America, the constellation Orion
sets in the south and the southwest
Eratosthenes of Syene is generally credited with using the angle of the noon Sun at Alexandria and Syene to determine the
size of the earth
The Law of Inertia says that if an object is not acted on by any outside force,
its acceleration will be zero
The planet Neptune was located because
its gravity disturbed the orbit of Uranus.
Galileo said that a moving object with nothing pushing or pulling on it will always
keep moving at the same speed
The Law of Inertia states that a moving object will
keep moving if no force acts on it.
A unit of mass is the
kilogram
The closest star to the North Celestial Pole that is visible to the naked eye is
polaris
The ancient Greeks insisted that a worthwhile model of a situation had to
predict what really happens.
By making extensive observations of planetary motion, Tycho Brahe
provided only a lot of accurate data.
Aristotle said that a moving earthly or 'mundane' object with nothing pushing or pulling on it will always
slow down and stop.
For the ancient Greeks, the most basic of several clues that the Sun is farther from the Earth than the Moon came from
solar eclipses.
The first telescope was (possibly) built by
someone in the netherlands
Stars that appear close together in the sky are
sometimes close to each other in space
When Galileo dropped a wooden ball and a heavier iron ball at the same time, he found that
sometimes the wooden ball hit first, sometimes the iron one hit first.
Pythagoras proposed that the Earth was round probably because he
thought that the sphere was the simplest and most elegant shape.
The purpose of a scientific model is
to predict the results of observations on real systems.
In the picture that we used in class, with the Sun above the top of the picture and the Earth shown with its North Pole facing you, the part of the Earth that is experiencing sunset would be
to the left of the North Pole in the picture.
At 8pm, you see that the pointer stars of the Big dipper and the star Polaris are arranged in a vertical line. At what time would you see them arranged in a horizontal line?
1:59:00 am the next day
In addition to measuring the positions of all the planets all the time, Tycho Brahe measured them to an accuracy of
1/60 degree of arc.
At 8pm, you see that the pointer stars of the Big dipper and the star Polaris are arranged in a vertical line. At what time, give or take a minute or so, would you see them arranged at 45 degrees to the vertical?
11 pm the same day
The time from one Full Moon to the next is 29.5 days. The length of a sidereal month is
27 days
A suborbital rocket such as an intercontinental ballistic missile or perhaps a passenger rocket from North America to Australia is most likely to leave the Earth's atmosphere at a speed of
4 miles per second
You see a waning quarter Moon high in the night sky. What time is it?
5am
What total force will cause an object with a mass of 1kg to gain 5 meters per second every second?
5n
At 8pm, you see that the pointer stars of the Big dipper and the star Polaris are arranged in a vertical line. How long, give or take a few minutes, would you need to wait to see them arranged in a horizontal line?
6 hours
Aristarchus of Samos is known for a number of things. One of them was
A model in which the Earth rotates on its axis and revolves around the Sun.
Which of the following computer programs is the most likely to be considered a scientific model:
A simulation, using currently accepted physical laws, of waves crashing on the beach.
Most of the ancient Greek astronomers believed that the Earth was fixed at the center of the universe. There was one, however, who thought that the Sun was fixed and a rotating Earth moved around the Sun. That was
Aristarchus of Samos.
You read in an Astronomy book that the temperature at the center of the Sun is 30,000,000 degrees Kelvin. How do you suppose this number was determined?
By using a model of the Sun that correctly accounts for everything that has been measured so far.
an area of the sky that is marked by a recognizable pattern of stars is called
Constellation
One observation that Aristotle used to justify a spherical model of the Earth was that the
Earth casts a curved shadow on the Moon during a lunar eclipse.
Although most records from that time were lost in the burning of the Great Library at Alexandria, most historians say that the first actual measurement of the Earth's circumference was made in the 3rd century BCE by
Eratosthenes of Syene
Gary the ghostbuster takes his crew, with a truckload of cameras and electronic instruments, to a house that is supposed to be haunted. Sure enough, the ghost shows up and does an on-camera interview while the instruments record all sorts of odd readings. After Gary's press conference and TV show, a skeptical scientist takes the same sort of equipment to the same house on a similar evening and records nothing but cricket noises and dogs barking. Gary's evidence is ignored by the scientific community because
Gary's observations were not reproduced.
Which of the following statements is an observation of the natural world? again
I saw a full Moon last night.
Which of the following statements is an observation of the natural world?
I saw the Moon rise at 6:52pm yesterday.
Other people look near Betelgeuse. They see the star and confirm her report. She becomes famous as the discoverer of the first green star.
I saw the Sun rise and set during the same clear 24-hour day in the continental United States.
Which of the following statements is the most likely to be a reproducible observation?
I saw the Sun set at 4:55pm on December 22 in Richmond VA.
The star Sirius can be located by using the pointer stars in
Orion.
The International Space Station (ISS) is in a roughly circular orbit near the surface of the Earth, moving at around 5 miles per second. Suppose that it is desired to raise it to a new circular orbit, farther from the surface by having the space shuttle give it one or more short boosts. Which of the following schemes will work?
Increase its speed to 6 miles per second and then give it another speed boost when its distance from the Earth stops increasing.
The Ptolemaic System continued to be accepted long after such people as Aristarchus and Copernicus had proposed alternatives. All of the following reasons why it lasted so long are at least partly true. Which reason is the one that would be stressed by the philosophy of science that we have been discussing?
It correctly predicted what was observed and thus did not need to be replaced.
Joseph Weber designed a series of devices to detect ripples in spacetime, called gravitational waves. After several years of effort, Joe announced that he had detected gravitational waves. He built several versions of his devices and they all detected the waves. When other people tried to build similar devices, none of them detected anything at all. Joe's evidence was ignored by the scientific community because
Joe's observations were not reproduced.
The statement that the orbit of each planet is an ellipse with the Sun at one focus is due to
Kepler.
Mars is farther from the Sun than Earth. Which of the following statements is true?
Mars takes longer to go around the Sun than Earth and moves more slowly than the Earth does.
Mercury is closer to the Sun than Earth. Which of the following statements is true?
Mercury takes less time to go around the Sun and moves faster than the Earth.
We can use the pointer stars in the Big Dipper to locate a point in the sky near the
North Celestial Pole.
You are looking down on the Earth from a spacecraft hovering far above. After watching for a while, you notice that, from your perspective, it is rotating counterclockwise. The part of the Earth that is directly below you must be the Earth's
North Pole.
Sarah reports that she saw a green star close to the star Betelguese. Actually she did not even look there. The most likely outcome of her fraud is that:
Other people look near Betelgeuse. They do not see the green star, and attack her report as a mistake or a fraud.
Sarah reports that she saw a green star close to the star Betelguese. She really saw it and was quite surprised. The most likely outcome of her report is that:
Other people look near Betelgeuse. They see the star and confirm her report. She becomes famous as the discoverer of the first green star.
Which of the following statements is falsifiable?/
Passenger pigeons are extinct.
Which of these was the Solar System model that assumed the Earth is fixed and the Sun, Moon, and planets all move on epicycles that, in turn move on circular orbits around the Earth?
Ptolemaic model.
The Greek philosopher who guessed that the Earth is a sphere because that is the most elegant and simple shape was
Pythagoras.
You would expect to see a waxing crescent Moon
Setting in the West right after the Sun.
Which of Kepler's Laws governs how a particular planet speeds up and slows down?
The Equal Area Law.
Which of the following statements is falsifiable
The Minoans were the first civilization on Crete.
Which of the following statements is falsifiable?
The Moon is made entirely of cheese.
When Newton calculated the magnitude of the acceleration of Earth's Moon, and compared it to the acceleration of falling objects on the surface of the Earth, he found that
The Moon's acceleration was smaller.
From his observations of the phases of Venus, Galileo concluded that
The Ptolemaic Model is wrong.
An early measurement of noon Sun angles at the summer solstice at Alexandria and Syene needed one additional piece of information in order to determine the size of the Earth.
The distance between Alexandria and Syene.
Newton's explanation of Kepler's Laws relied upon a force that
acts on all objects.
A horse is pulling a cart along a road. Which of the following pairs of forces is an action-reaction pair?
The force of horse on the road and the force of the road on the horse.
A book, weighing 10 Newtons, sits on a table. Which of the following pairs of forces is an action-reaction pair?
The force that the book exerts on the table and the force that the table exerts on the book.
The motion of the Moon around the Earth causes
The phases of the Moon.
Copernicus said that the Earth and planets orbiting the Sun caused
The retrograde motion of the planets.
Einstein's Theory of Relativity has passed every observational test for over 100 years. Among other things, it predicts that no material object can go faster than the speed of light. Fred Zveistein (twice as smart as Einstein) has a new theory that predicts that some material objects can go faster than light. Fred presents his new theory at a scientific meeting (in 2009). Which of the following would be the most likely reaction of the scientists at the meeting to this new development?
There is great disinterest because there is no need to replace a theory that has passed every observational test. Nobody at all comes to Fred's talk.
Which of the following astronomers is regarded as an early example of government-supported Big Science.
Tycho Brahe
Copernicus said that the daily motions in the heavens were caused by the
earth turning on its axis.
One property of a model such as the shape of the Earth is the number of adjustable parameters it has --- the number of numbers that are needed to determine the model. If this number is very large, that is regarded as
a bad thing since it lets the model fit many possible measurements.
A sidereal day is
a few minutes shorter than a solar day
The Celestial Sphere is
a map of the stars
The time it takes for the Celestial sphere to rotate once relative to the Earth is called
a sidereal day
You see a waxing Gibbous Moon directly south. What time might it be?
about 10pm
In comparison to the Copernican Theory, the Ptolemaic Theory made predictions that were of
about the same accuracy.
In comparison to the established, earth-centered theory, the Copernican Theory of planetary motion made predictions that were of
about the same accuracy.
Galileo's approach to science is best described as based on
active construction of simplified experiments
In addition to being accurate, Tycho Brahe's observations focused on measuring the positions of the planets
all the time.
In comparison to Kepler's Laws of Planetary Motion, Newton's theory of Universal Gravitation predicted
almost the same motions but with corrections.
The brightest star in the constellation Centaurus might be named
alpha centauri
The ancient Greeks were able to calculate the distance from the Earth to the Moon by using a geometrical model of
an eclipse of the Moon
Kepler found that the orbit of Mars is best described as
an ellipse
Kepler's First Law of Planetary Motion is that the orbit of each planet is
an ellipse with the Sun at one focus.
Once its rockets have ceased firing, an Intercontinental Ballistic Missile will follow a path that is best described as
an ellipse with the center of the Earth at one focus.
Kepler's Laws
are explained by a force that attracts each planet to the Sun.
When Galileo dropped a wooden ball and a heavier iron ball at the same time, he was expecting that
both balls would always hit at exactly the same time.
Suppose that you drop two objects from the same height at the same time. Both objects are heavy enough to be unaffected by air resistance. If one object is twice as heavy as the other, Galileo predicted that
both objects would hit the ground at the same time.
Galileo's approach to understanding moving objects was to
build things that he could measure.
From the way that lunar eclipses happen, the Ancient Greeks were able to
calculate the distance from the Earth to the Moon.
One observation that we are fairly sure helped to convince the Greeks that the Earth is spherical rather than flat is
constellations that could be seen from Egypt but not from Greece.
If you are looking down over the north pole of the Earth, you will see the Earth rotate
counterclockwise.
Copernicus said that the rotation of the Earth on its axis caused the
daily motions in the heavens.
For Copernicus, a critical inconsistency in the final version of the Ptolemaic System was that it
did not really have anything fixed in place at the center of the universe.
Copernicus said that the retrograde motion of the planets was caused by the
earth and the planets orbiting the Sun.
One objection to a solar system model that has the Earth moving around the Sun is that we would then see nearby stars seem to shift back and forth relative to more distant stars. The correct answer to that objection is that
even the closest stars are so far away that the shift is very small.
The time from one solar noon to the next is
exactly 24 hours
A time of 24 hours is
exactly equal to a solar day
Ancient astronomers were puzzled by the planets because they
execute retrograde loops.
Aristotle pointed out that assuming that gravity pulls everything toward a common center
explains why the Earth is spherical.
Kepler was an early advocate of the Copernican Theory. When he applied it to Tycho's observations, it
failed but led to a better theory
A star that is named Delta Cepheus is most likely
fairly dim star in the constellation Cepheus..
The International Space Station (ISS) is in a roughly circular orbit near the surface of the Earth, moving at around 5 miles per second. Suppose the Space Shuttle pushes it and quickly increases its speed to 6 miles per second. The ISS will then
follow an ellipse that rises and then descends again.
A constellation is a collection of stars that
form a pattern in our sky.
Tycho Brahe's work at Uraniborg was
funded by a large fraction of the national budget of Denmark.
Who discovered Newton's First Law of Motion?
galileo
Freely falling objects with different masses fall with the same acceleration because
gravity exerts more force on the more massive object.
The force of gravity explains
how planets move and how the tides work.
The force of gravity explains
how the tides work but not how lightning works.
When Newton calculated the magnitude and direction of the acceleration for a planet that was following Kepler's Laws, he found that the magnitude of the acceleration was
inversely proportional to the square of the planet's distance from the Sun.
If the acceleration of an object is zero, its speed
is not changing.
The Ptolemaic System was replaced when
it came into conflict with observations.
The astronomers of Copernicus's time rejected his model of the Solar System mostly because
it did not account for observations any better than the Ptolemaic System
one reason that the Copernican System failed to fit Tycho's observations was that
it used circular orbits instead of ellipses
Aristarchus measured the angle between the Sun and the Moon when exactly half of the Moon was illuminated. If the Sun were actually just two or three times as far away as the Moon, he would have found that angle to be
less than 90 degrees by an amount that was easy for him to measure.
Aristarchus measured the angle between the Sun and the Moon when exactly half of the Moon was illuminated. He found this angle to be
less than 90 degrees by an amount too small for him to measure.
Compared to a sidereal month, the time from one full Moon to the next is
longer by 2.5 days
tycho Brahe's main contribution to the understanding of planetary motion was to
make extensive observations
As the two foci of an ellipse are brought together, the shape of the ellipse becomes
more like a circle around the foci.
As the two foci of an ellipse are moved apart, the shape of the ellipse becomes
more like a line between the foci.
In a solar day, the sun comes back to the same place in the sky but, in relation to the distant stars, the Earth actually rotate
more than one revolution
The stars that form the Big Dipper (in England it is called the Plough) are
mostly at nearly the same distance from the Earth, but with exceptions.
When compared to planets that are closer to the sun, planets that are farther from the sun
move slower on the average
In one day, the position of the Sun on the Celestial Sphere
moves eastward along the ecliptic by 1°.
At midsummer in Murmansk (which is the largest city north of the Arctic Circle), the Sun stays above the horizon for several days. This observation would conflict with the predictions of a model of the Sun's motion that has the Sun
moving over and under a flat Earth.
As seen from North America, the constellation Casseopeia
never sets
As seen from North America, the constellation Ursa Major
never sets
A unit of force is the
newton
When a bullet is fired from a gun, the bullet keeps moving after it leaves the gun barrel because
no force stops it
When an arrow is fired from a bow, the arrow keeps moving after it leaves the bow because
no force stops it
Tycho Brahe's careful observations of the planets agreed, to within observational error, with
none of these systems
The earliest known measurement of the circumference of the Earth used
noon Sun angles at two locations to determine the angle between the Earth radii to those locations
Galileo is generally aknowledged to be the first to
observe the heavens with a telescope.
The distance from the Earth to the Sun is
one astronomical unit.
The daily rising and setting of the Sun happens
only south of the arctic circle and north of the antarctic circle.
One observation that Aristotle used to justify a spherical model of the Earth was that
southern constellations were seen higher in the sky in Egypt than in Greece
Aristotle said that the amount of force on a moving earthly object determines its
speed
According to Kepler's Laws of Planetary Motion, as planets orbit the sun, they
speed up when closest to the Sun
We can use the pointer stars in Orion to locate a point in the sky near the
star sirius
At midsummer in Murmansk (which is the largest city north of the Arctic Circle), you would expect the Sun to
stay above the horizon all day, every day
The idea of a scientific fact presents difficulties for the falsificationist philosophy that we have been discussing because that philosophy insists that every scientific statement is
subject to change
The time when the noon sun is highest in the sky is called
summer solstice
Many primitive cultures have a model of the Sun's motion in which the Sun passes underneath a flat earth. This model predicts
that everyone on Earth sees the Sun rise and set each day
The stars, as seen from the Earth, appear to be attached to
the Celestial Sphere, a sphere that surrounds the Earth..
In Newton's Theory,
the Earth and Moon move around a common point which, in turn, goes around the Sun
An artificial satellite such as the International Space Station stays up because
the Earth curves out from under it as fast as it falls.
The observation that there are constellations that can be seen from Egypt but not from Greece convinced the ancient Greeks that
the Earth is round.
In the Ptolemaic model of the Solar System,
the Earth was fixed and the planets and the Sun moved on epicycles which, in turn, went around the Earth.
Aristotle pointed out that a spherical Earth would explain why
the Earth's shadow on the Moon is curved during a lunar eclipse.
In Newton's Theory of planetary motion,
the Sun and Earth move around each other.
From the way that solar eclipses happen, the ancient Greeks concluded that
the Sun is farther from the Earth and larger than the Moon
aristotle pointed out that a spherical Earth would explain why
the constellations visible from Egypt are somewhat different than the constellations visible from Greece.
By measuring the angle between the Sun and the Moon when the Moon was in its first or third quarter, the ancient Greeks were able to calculate
the distance from the Earth to the Sun.
The path of the Sun on the Celestial Sphere is called
the ecliptic
According to Galileo, a thrown spear keeps moving after it has left the spear thrower's hand because
the force of friction with the air is not enough to stop the spear.
According to Aristotle, a thrown spear keeps moving after it has left the spear thrower's hand because
the force of the air disturbed by the spear keeps it in motion.
Suppose that you drop two objects from the same height at the same time. Both objects are heavy enough to be unaffected by air resistance. If one object is twice as heavy as the other, Aristotle would predict that
the heavier object would hit the ground long before the lighter one
Suppose that you drop two objects from the same height at the same time. Both objects are heavy enough to be unaffected by air resistance. If one object is twice as heavy as the other, Aristotle predicted that
the heavier object would hit the ground long before the lighter one.
Suppose that you drop a wooden ball and an iron ball, both the exact same diameter, from the same height at the same time. Aristotle would predict that
the iron ball would hit the ground long before the wooden ball.
The changing phases of the Moon are caused by
the motion of the Moon around the Earth.
Aristotle said that the spherical shape of the Earth was
the natural result of gravity pulling everything toward a center.
The Summer Solstice is the time when
the noon sun is highest in the sky.
The ecliptic is
the path of the Sun on the Celestial Sphere.
The first major failure of the Ptolemaic Theory to predict the results of observations was
the phases of Venus.
The ancient Greeks were able to estimate the distance from the Earth to the Sun by using
the quarter phases of the moon
Suppose that an object with a mass of one kilogram and an object with a mass of two kilograms are both in free fall near the Earth's surface. As compared to the one kilogram object, the two kilogram object accelerates
the same because gravity pulls on it more strongly and it has more inertia.
The ancient Greeks argued that the Earth cannot be moving because such a motion would cause apparent shifts in the positions of stars. This argument was wrong because
the stars are so far away that the shifts due to the Earth's motion are extremely small
A sidereal day is the time it takes for
the stars to come back to the same positions in the sky.
One reason that temperatures are higher in the summer than in the winter is that
the sun is higher in the sky in the summer.
One reason that temperatures are lower in the winter than in the summer is that
the sun is lower in the sky in the winter.
The fact that the International Space Station is above most of the Earth's atmosphere is important because it means that
there is no air friction to slow the space station down.
Einstein's Theory of Relativity has passed every observational test for over 100 years. Among other things, it predicts that no material object can go faster than the speed of light. Fred Zveistein (twice as smart as Einstein) has a new theory that predicts that some material objects can go faster than light. Fred presents his new theory at a scientific meeting (in 2009). These meetings have several talks going on at the same time, so people normally move from one room to another to hear the talks they are interested in. When Fred gets up to talk, everyone leaves the room to go to other talks. The reason for this behavior is that
there is no interest in replacing a theory that has passed every observational test.
In the picture that we used in class, with the Sun above the top of the picture and the Earth shown with its North Pole facing you, the part of the Earth that is experiencing sunrise would be
to the right of the North Pole in the picture.
When Newton calculated the magnitude and direction of the acceleration of Earth's Moon, he found that the direction was
toward the Earth.
When Newton calculated the magnitude and direction of the acceleration for a planet that was following Kepler's Laws, he found that the direction of the acceleration was
toward the Sun.
Which of the following phases of the Moon would be seen high in the south at dawn?
waning quarter
Just after sunset, you might find
waxing crescent Moon setting in the west.
You see the Moon almost directly in the south at 10pm. What phase is it?
waxing gibbous
Astronomy is known for claiming to have measured many things that cannot possibly be probed directly. These measurements are made by combining actual measurements with
well-tested models.
the sun usually sets in the
west
Retrograde Motion refers to the
westward motion of the planets relative to the stars.
One advantage of the spherical Earth model is that it completely explains
what holds up the surface of the Earth
A disadvantage of the flat Earth model is that it fails to provide a complete explanation of
what holds up the surface of the Earth.
The Law of Inertia says that if an object is not acted on by any outside force, its acceleration
will always be zero
The idea that a worthwhile model of a situation must predict what is actually observed seems to have started
with the ancient Greek philosophers
If an object is moving at constant speed in a straight line, its acceleration is
zero
