The Solar System Chapters 1-4
Which of the following is the Earth NOT located in?
-- you can't fool me, we are located in all of the above -- the Milky Way Galaxy The Virgo supercluster the Local Group of galaxies the solar system
Which of the following is the same number as 4.95 x 10^-7?
0.000000495
While watching a star, you see it moves 15 degrees across the sky. How long have you been watching it?
1 hour
An astronomy textbook, when printed out, weighs four pounds on the surface of the Earth. After finishing your course, you are so tired of the book, you arrange for NASA to shoot it into space. When it is twice as far from the center of the Earth than when you were reading it, what would it weigh? (Note, assume that the book has been moving away from the Earth, not falling freely around it.)
1 lb
A star chart with a horizon-view shows what percentage of the total celestial sphere?
25%
How long is the precession cycle?
26,000 years
What is 9.027 x 10^5 times 3.013 x 10^7? Try to answer this without using a calculator or any calculation aid. Use the method detailed in the video on scientific notation. Approximations are ok.
27 x 10^12
You are observing the light from a star located in a distant galaxy. The galaxy lies 60 million light years away. By analyzing the starlight, you can tell that the start is about 10 million year old. The expected lifetime of a star of this mass is 100 million years, at which point it will explode as a supernova. How long will it be before the star explodes as a supernova?
30 million years
Light travels 3 x 10^5 meters every second. That number written out is
300,000 meters
Scale of Earth's Orbit. If you were to use a 3-foot balloon to represent the Sun, how far apart would it have to be from the Earth to be an accurate scale model?
330 feet
A "jiffy" is defined as the length of time it takes for light to travel one centimeter. This is roughly 0.000000000333564 s. What is these represent this number in scientific notation?
333.564 x 10^-12 s
Relative size of the Moon and Earth. How many Moons can fit across the diameter of the Earth?
4
Express the following number in scientific notation and round to the nearest million: 489,283,465
4.89 x 10^8
A planet whose distance from the Sun is 3 A.U. would have an orbital period of how many Earth-years?
5.2
Express the following in scientific notation: 0.0000000562
5.62 x 10^-8
A star chart with an overhead-view shows what percentage of the total celestial sphere?
50%
Into how many constellations is the celestial sphere divided?
88
In the scenario described above, how long will it be until we see the light from the supernova explosion?
90 Million years
The eccentricity of Mercury's orbit is 0.206. Which of the shapes below best characterizes an orbit with this eccentricity?
A
Galileo found the rotation period of the Sun was approximately:
A month
A large body in space that consistently makes its own light (instead of merely reflecting another body's light) is called
A star
The figure below shows a planet's orbit around it's Sun. The ten positions shown (A-J) are positions that the planet is in one month apart. At which point is the planet moving the slowest?
A.
The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was:
Copernicus
Why do many people consider Isaac Newton one of the greatest scientists who ever lived?
He formulated the laws that govern all motion in the universe He combined the work of Galileo, Brahe, and Kepler into one framework He figured out the mathematical form of a law of universal gravity all of the above none of the above (not a, not b, not c)
Explain why it is ok to account for the Sun's daily motion by assuming it is fixed on the celestial sphere, but not OK to make the same assumption for its motion over weeks and months.
It is ok to assume that the Sun is fixed on the celestial sphere over the course of a day because the Sun moves very slowly relative to the celestial sphere and the stars on it. Over the course of a day, it moves very little, less than 1 degree of arc. Over weeks and months it moves greatly, going all the way around in 365 days (in fact it does this because the Earth is moving around it, not the other way around).
The scientist who formulated the three laws of planetary motion by analyzing the data on the precise location of planets in the sky was:
Johannes Kepler
What is a larger unit of length, the A.U. or the light-year?
Light Year
Which planet has an orbital distance about 1.5x that of the Earth?
Mars
The Law of Universal Gravitation was developed by:
Newton
Where on Earth would you be if Polaris was at your Zenith?
North Pole
Where on Earth would you be if Polaris was at your zenith?
North Pole
The figure below shows three pairs of asteroids. In which panel is the force on the asteroid on the left the smallest?
Panel A
The figure below shows three pairs of asteroids. In which panel is the force on the asteroid on the right the smallest?
Panel A
Modern Scientific Theories are NOT:
Perfect
The place in a planet's orbit that is closest to the Sun is called:
Perihelion
When a comet like Comet Hale-Bopp comes closest to the Sun in its orbit, we say that it is at:
Perihelion
Figure 1 from the lecture tutorial, Seasonal Stars, shows the Earth and Sun along with the constellations of the Zodiac. In what constellation will the Sun be in four months after the date shown?
Pisces
The figure below shows the orbits of several planets around identical stars. Which of the planets will take the longest time to orbit its star?
Planet in panel A
The star that is currently closest to the North Celestial Pole is:
Polaris
The figure below shows the Earth, the Sun, and several positions on the Earth's surface. If you lived at which of the labeled positions would you be experiencing 12 hours of daylight and 12 hours of night over the course of a 24 hour period?
Position C
The figure below shows the orbit of a single star, Four positions on this orbit are highlighted. Which letter (A-D) represents the position that the planet would be moving the slowest in its orbit among the 4 shown?
Position C
The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is:
Ptolemy
The most accurate Greek attempt to explain planetary motion was the model of:
Ptolemy.
Of these, which is the largest?
The Milky Way Galaxy The Universe -- Earth -- The Solar System Jupiter
The natural object (not one that humans built) in space that's closest to Earth is
The Moon
The Earth's escape speed (the speed you need to get away forever) is about 25,000 miles per hour. Escape speed depends on the gravity of the object trying to hold the spacecraft from escaping. Based on your understanding of gravity, how will the escape speed from the Moon compare to the escape speed from Earth?
The Moon's escape speed will be smaller than Earth's
The star that provides energy for life on Earth is
The Sun
A small, Earth-like planet is in orbit near to a star. In the same system, a huge, Jupiter-like planet orbits far from the star. Which of the two planets do you think will move around their star in the greatest amount of time?
The huge, Jupiter-like planet
After a long night of cramming for a test, your college room-mate hits his head forcefully against the wall of your room in despair. According to Newton's 3rd Law, as he exerts a force against the wall, there must be an equal and opposite force. How does that opposite force show itself in this case?
The wall exerts a force on your room-mate's head and he has a headache
The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was:
Tycho Brahe
Which of the choices below correctly lists things in order from largest to smallest?
Universe, Local Group, Milky Way, Solar System
A fatal flaw with Ptolemy's model is its inability to predict the observed phases of:
Venus and Mercury
A single star in the process of forming starts by spinning slowly (while it is quite large and relatively cool.) As the star collapses under the pull of its own gravity, its size decreases. As a result, its rate of spinning:
Will Increase
The point in the sky directly above your head at any given time is called the
Zenith
Newton showed that to change the direction in which an object is moving, one needs to apply:
a force
Galileo found the rotation period of the Sun was approximately
a month
A fact is ...
a simple observation that has been repeatedly confirmed and for all practical purposes is accepted as "true."
If the Sun had a solid surface and you wouldn't instantaneously melt, approximately how long would it take for you to walk around the Sun (circumference)?
about 100 years
How many of our Moons would fit across the diameter of the Sun?
about 440
We now know that the orbit of a stable planet around a star like the Sun is always in the shape of:
an ellipse
According to Copernicus, the retrograde motion for Mars must occur:
at opposition, when the Earth overtakes Mars and passes between Mars and the Sun.
From a city in the U.S., where in the sky would you look to see a star that is not turning with the motion of the sky in the course of a night?
at the north celestial pole
Where on Earth do stars always circle the zenith (and never rise and set)?
at the north pole
An effective theory must:
be continuously tested.
How did Eratosthenes measure the size of the Earth?
by measuring the height of the Sun in the sky on the same day in two cities at different latitudes
To come up with the precise mathematical form of his law of gravity, Newton first had to invent the mathematical techniques that we now call:
calculus
On the celestial sphere, halfway between the celestial poles lies the
celestial equator
The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:
constellations
The places where the Sun crosses the equator are called the:
equinoxes
To leave the gravitational pull of the Earth, and explore other planets, satellites must have at least:
escape velocity
The Ptolemaic model of the universe:
explained and predicted the motions of the planets with deferents and epicycles.
Which of the following was NOT done by Hipparchus, the great ancient astronomer?
explained retrograde motion
Why did early civilizations observe constellations?
for practical reasons, such as navigation and helping to determine seasons
Which of the following statements about forces is FALSE?
forces cause an acceleration to take place forces always occur in equal and opposite pairs where there is no force, objects continue to move the way they were moving There are places on Earth where all forces are absent
When it comes to our place in the solar system today, which model do we accept?
heliocentric
From a location in the United States of America, a star is observed to be rising due East. Where will this star be located 6 hours later?
high in the southern sky
You are on a camping trip, far away from city lights. You look up into the dark night sky, and see lots of stars, some brighter, some dimmer. All the stars you see with your unaided eye are
in the Milky Way Galaxy
The Ptolemaic model probably persisted for all of these reasons EXCEPT:
it accounted well for Galileo's observations of the phases of Venus.
Which of the following statements about the force of gravity is FALSE?
it is a universal force, which acts everywhere in space its strength decreases as the square of the distance its strength is inversely proportional to the mass: the more mass, the less gravity the force never becomes zero it causes the paths of the planets to be ellipses and not straight lines
The Ptolemaic model probably persisted for all these reasons EXCEPT:
it was consistent with the doctrines of the Catholic Church. it had the authority of Aristotle behind it. it used perfect circles, which appealed to geometry. it explain why stellar parallax was not observed by the Greeks. It accounted well for Galileo's observations of the phase cycle of Venus.
The image below is of the Pinwheel Galaxy (M101). This galaxy lies about 21 million light years from Earth. This image is showing how the Pinwheel Galaxy
looked 21 million years ago.
In Newton's Law of Gravity, the force of gravity goes up as the:
mass goes down distance goes up mass goes up distance goes down more than one of the above
According to the geocentric view, everything in the heavens had to go around the Earth, which was the center of the universe. What objects did Galileo discover with his telescope that clearly didn't go around the Earth?
moons around the planet Jupiter
The figure below shows a planet's orbit around it's Sun. The ten positions shown (A-J) are positions that the planet is in one month apart. Does the planet appear to be traveling the same distance each month?
no
If the distance between two asteroids is doubled, the gravitational force they exert on each other will:
one fourth as great.
The slow tipping of the Earth's axis in a circle with a period of about 26,000 years is called:
precession
That Polaris will not always be the pole star is due to:
precession shifting the celestial pole.
The force of gravity varies with the:
product of the two masses. inverse of the distance separating the two bodies. inverse square of the distance separating the two bodies. Both A and B are correct. Both A and C are correct.
When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:
retrograde motion
The place the Sun stops its northward motion along the ecliptic is the:
summer solstice.
Which of the following is NOT a result of the Earth's precession?
the Earth wobbles (like a spinning top) with a period of 26,000 years where the Earth's axis points in the sky changes over the centuries and millennia Polaris will no longer be the North Star in several thousand years the stars twinkle when seen from the surface of planet Earth the signs of the zodiac most astrologers use are no longer in accord with the constellations in which the Sun is currently found over the course of the year
If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?
the Earth's axis is tilted by about 23 degrees from the vertical
The Astronomical Unit (AU) as defined by astronomers is
the average distance between the Earth and the Sun
A graduate student in geology who grew up in Florida (near the southernmost tip of the United States) gets to accompany her research professor to the North Pole. What will be different at the North Pole from the way she remembers the sky in Florida?
the celestial equator is on the horizon the way (and whether) the stars rise or set -- all of the above would be different from the way it is in Florida -- all of the above (a - c) would be the same as in Florida
Some Canadian troops are sent (as part of a U.N. peacekeeping force) to a country located on the Earth's equator. At night, when homesickness makes them gaze sleeplessly at the stars, which of the following will be familiar to them (the same at the equator as in Canada):
the celestial poles are on the north and south points of the horizon the celestial equator is overhead and passes through the zenith all stars rise and set (no star remains in the sky all night long) all stars are above the horizon exactly half a day -- none of the above are the same on the equator as in Canada --
A year is defined as:
the time it takes for Earth to complete an orbit around the Sun.
Scientists today do not accept the Ptolemaic model because:
the work of Tycho and Kepler showed the heliocentric model was more accurate.
Astronomers discover a new comet that orbits the Sun, but has its aphelion (the furthest point in its orbit) beyond Neptune. Astronomers studying this comet have the right to expect that it:
will follow Newton's laws of motion
Of these which is the closest to us?
-- The Moon -- Mars The Sun The center of the Milky Way The closest spiral galaxy
A circular orbit would have an eccentricity of:
0
How much stronger is the gravitational pull of the Sun on Earth, at 1 AU, than it is on Saturn at 10 AU?
100X
According to Kepler's Third Law, a planet orbiting at a distance of 5 AU will have an orbital period closest to
11 years
If you were to use a 1-foot (12-inch) basketball to represent the Sun, how far would it have to be from Earth to be an accurate scale model?
110 ft
From horizon to opposite horizon, the sky takes up how much angular distance?
180 degrees
Relative size of the Moon's orbit. How many times could the Moon's orbital diameter fit between the Earth and the Sun?
220
A star is 230 light years away. The light we see tonight from that star left it
230 years ago
What is the speed of light in miles per hour? I know this can be looked up on the web, but I encourage everyone to practice the calculation yourself using the conversion factors below. On tests you will not be able to use Google. Note: 1 mile = 5280 ft; 1 m = 3.281 ft; 1 km = 1000 m; 60 s = 1 min; 60 min = 1 hr
6.7 x 10^8 mph
Express the following in scientific notation: 634,000
63.4 x 10^4
On which of these assumptions do Ptolemy and Copernicus agree?
All orbits must be perfect circles.
The heliocentric model was actually first proposed by:
Aristarchus
When the authors of our textbook say that astronomers are like police detectives trying to solve crimes, they are explaining that:
Both astronomers and detectives must test their hypotheses against any evidence that they gather
The laws of nature (as determined by scientists)
Can never, ever change once they are written down in textbooks Are constructed from many observations, hypotheses, and experiments Apply both on Earth and among the stars Are often written in the language of mathematics -- More than one of the above --
The figure below shows the Earth, the Sun, and several positions on the Earth's surface. What is the approximate date that this image depicts? Assume the the north pole is on the top.
December 21st
What celestial line is a product of the Earth's orbit around the Sun?
Ecliptic
Where on Earth can you observe all the stars in the sky over an entire year?
Equator
If Taurus is now rising at sunset, which constellation will rise at sunset next month?
Gemini
The idea that objects (in the absence of an outside force) tend to continue doing what they are already doing is called the law of
Intertia
Figure 1 from the lecture tutorial, Seasonal Stars, shows the Earth and Sun along with the constellations of the Zodiac. In what constellation will the Sun be in on the date shown?
Scorpius
Relative size of the Sun and Earth. In the model from the previous problem, which of the items below could be used to represent the Earth?
Small Grape
Star A is shown in the figure below at a position labelled "Position 5". In what direction would you look to see Star A in this position?
Southeast, Mid-Altitude
Which of these was NOT seen telescopically by Galileo?
Stellar parallax
Let's say we find a star that is located on the points or circles in the sky listed in the answer choices below. Then, on the same night, we move to a location on Earth that is some significant distance from our first location. There will now be a different star at or on:
The Zenith
The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:
The Zodiac
Which of the following was NOT a contribution of Galileo to astronomy?
The changing appearance of Saturn's rings corresponds to our seasons. Sunspots showed the Sun was rotating on its axis, like the Earth does. The four moons of Jupiter are a model for the solar system motions in general. The craters and mare of the Moon prove it a world in its own right. The phases of Venus prove it orbits completely around the Sun.
An object is moving with a constant velocity. Which of the following statements is true?
The net force on the object is zero
Where would you be if the Sun passes through your zenith on December 21st?
Tropic of Capricorn
Which of the following has the greatest density?
a cubic meter of snow a cubic meter of air a cubic meter of astronomy textbooks (the printed versions, not the on-line ones) a cubic meter of feathers a cubic meter of lead
About how many stars are visible on a clear, dark night with the naked eye alone?
a few thousand
The asteroid belt is
a zone where rocky chunks orbit between Mars and Jupiter
As seen from the continental United States, the Big and Little Dipper
are in the north circumpolar zone throughout the year
According to Kepler's third law, there is a relationship between the time a planet takes to revolve around the Sun and its
distance from the Sun
The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to
do experiments and observations about the predictions of the hypothesis
Which of the following is NOT an argument for showing that the Earth must be round:
during an eclipse of the Moon, the shadow of the Earth is always seen to be round when ships travel a large distance away, we see their hulls disappear first and their masts disappear last the height of the North Star changes as we travel to different latitudes photographs of the Earth from space always show a round body -- the Sun is seen blocking different constellations in the course of a year --
By the term universe, astronomers mean
everything that we can observe
When the Sun rises, it is located in the constellation Gemini. When the Sun sets later that same day, it will be:
in the constellation Gemini.
In the Northern Hemisphere, the altitude (height in degrees above the horizon) of the North Star is always roughly equal to the
latitude of the observer
When a planet, in its orbit, is closer to the Sun, it:
moves faster than average
Modern scientific theories are NOT:
perfect
The south celestial pole and the north celestial pole lie in the sky directly above
the Earth's axis
Why do astronauts (and cans of soft drink) float around in the Shuttle instead of falling?
the Shuttle is falling around the Earth (and everything aboard is in free fall)
A light year is
the distance that light travels in one year
In an ellipse, the ratio of the distance between the foci and the length of the major axis is called:
the eccentricity
The Sun's apparent path around the celestial sphere is called
the ecliptic
The angular size of an object depends on which two quantities?
the object's actual size and its distance from us
The celestial sphere turns once around each day because
the planet on which we live is rotating
In Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Jupiter?
the planets moved on a small circle whose center, in turn, circled a point near the Earth
Someone who observes the sky every clear night in Boston for many years will NEVER get to see:
the south circumpolar zone
Seasons on Earth are primarily caused by:
the tilt of the Earth's rotational axis.