chapter 1-3 quiz & assignment Flashcards
which of the following sequences objects is in the correct order of increasing distance?
venus, saturn, moon, andromeda galaxy, polaris
moon, venus, saturn, polaris, andromeda galaxy
polaris, andromeda galaxy, moon, saturn, venus
andromeda galaxy, saturn, venus, polaris, moon
moon, venus, saturn, polaris, andromeda galaxy
what is the average distance from the earth to the sun?
1 Au
what is the implication if the distance to the nearest star is 4.2 light-years?
the light we see left the star 4.2 years ago
if you represent each star by a grain of sand, how much sand would it take to represent all the stars in the universe?
more than all the sand on all the beaches on Earth
how long would it take to count all the stars in the milky way galaxy at a rate of one star per second?
several thousand years
it takes light 1.3 seconds to travel from the moon to earth and 8 minutes for light to travel from the Sun to Earth. which statement is true?
the sun is 6.2 times farther from earth than the moon
the sun is 10 times farther from earth than the moon
the sun is 370 times farther from earth than the moon
the sun is 0.10 times farther from the earth than the moon
the sun is 370 times farther from earth than the moon
the speed of light is 3.0 x 10^5 km/s, and it takes 1.3 seconds for light to travel from the moon to earth. based on the info, what is the distance from the earth to the moon?
390,000 km
230,000 km
- 9 km
- 3 km
390,000 km
which of the following is largest?
size of a typical galaxy
size of Pluto’s orbit
distance to the nearest star (other than our sun)
1 light-year
size of a typical galaxy
which of the following statements best describes the sun?
generates energy by nuclear fusion
located 10 AU from Earth
orbiting the Solar system
located in the centre of the Milky Way
generates energy by nuclear fusion
which statement best describes the Milky Way Galaxy?
it is a spiral galaxy
it is comprised of several smaller galaxies
it is about 1,000 light-years in diameter
it is type of supercluster
it is a spiral galaxy
one light-hour is the distance that light travels an hour. how far is this, in kilometers? (recall the speed of light is 300,000 km/s
300,000 km
18 million km
100 million km
1.08 billion km
1.08 billion km
in the diagram, what is the diameter of jupiter? (scale 35,000 km)
about 7.0 x 10^4 km
about 7.0 x 10^5 km
about 1.4 x 10 ^4 km
about 1.4 x 10^5 km
about 1.4 x 10^5 km
roughly how many stars are in the milky way galaxy?
100 billion
if we say that an object is 1,000 ly away, how does that affect how we see it?
we see it as it looked 1,000 years ago
we see it as it would appear to our ancestors 1,000 years ago
we see it as it looked 1,000 ly ago
we see it as it is right now, but appears 1,000 dimmer
we see it as it looked 1,000 years ago
there approx 100 billion stars in our galaxy. if there 100 billion observable galaxies in our universe, what is a reasonable estimate for the total number of stars in the universe is?
- 0 x 10^22
- 0 x 10^20
- 5 x 10 ^18
30 x 10^22
1.0 x 10^22
what do we mean by observable universe?
the part of the universe that we can see with naked eye
the part of the universe we can see with telescopes
the part of the universe that could be observed in principle, including things that may require future technologies
the compendium of all objects that we have observed to date
the part of the universe that could be observed in principle, including things that may require future technologies
today the age of the universe is estimated in 13,700,000,000 years
- 37 x 10^6 y
- 37 x 10^7 y
- 37 x 10^8 y
- 37 x 10^9 y
1.37 x 10^9 y
how long does it take for light to travel from the sun to neptune?
several seconds
several minutes
several hours
several weeks
several hours
which of the following is the smallest?
size of a planet
1 AU
1 light-year
size of a typical galaxy
size of a planet
suppose we look at a photograph of many galaxies. assuming that all galaxies formed at about the same time, which galaxy in the picture is the youngest?
the one that is farthest away
the one that is reddest in color
the one that is bluest in color
the one that is closet to us
the one that is farthest away
how is a planet different from a star?
planets are larger than stars.
planets reflect light, while stars produce their own light
stars move faster in the sky than planets
planets are brighter stars
planets reflect light, while stars produce their own light
in the diagram, what is the diameter of mercury?
about 240 km
about 2400 km
about 24,000 km
about 240,000 km
about 2400 km
what is 1.95 billion the same as?
1.95 x 10^9
sirius the brightest star in the sky is about 9 ly away. if the speed of light became half of its present value, how far would Sirius be?
18 ly
if the distance from the sun to the earth is represented by roughly 15 meters, then what would the distance from the earth to the Moon on the same scale be?
About 30 meters
about 10 meters
about 1 metre
smaller than the width of your hand
smaller than the width of your hand
what does the solar system contain?
the sun, it’s planets, and some smaller bodies
the sun, galaxies, planets, and stars
the sun, planets, moons? and stars
the sun, planets, asteroids, and galaxies
the sun, it’s planets, and some smaller bodies
the nearest star to our solar system is alpha centauri at 4.0 x 10^16 m (4.3 ly away). the diameter of the sun is 1.4 x 10^9. how many suns would it take to line up adjacent to each other in order to reach alpha centauri?
2.8 x 10^7
what is 5.7 x 10^7 the same as
57 million
a spherical particle in the ring of saturn has a radius of about 1 m. the cross sectional area of the particle in the area of radiation flow is:
12.6 m2
what’s the approx diameter of the earth?
13,000 km
if we use 1 mm to represent 1 ly, how large in diameter is the milky way galaxy?
100 meters
the distance to a super galaxy might be
100 mpc
10 kpc
120 ly
10 au
100 mpc
what do we mean when we say the universe is expanding?
all galaxies are increasingly moving away from one another
if the denver airport were switched on, then in one second these photons travel to:
new york (1580 km)
alpha centauri (40,000,000,000,000 km)
the sun (150,000,000km)
moon (384,000 km)
moon (384,000 km)
approx 100 earths would fit in Jupiter. Jupiter’s radius must be ….times larger than earths radius
10
approx how many times larger than the diameter of a typical planet ( the earth) is the diameter of a typical star (the sun)?
100 times
a spherical particle in the ring of saturn has a radius of ab 1 m. the surface area of the particle in the area of radiation flow is?
3.14 m2
you are standing on earths equator. which way is Polaris, the north star?
on the northern horizon
by locating the north celestial pole (NCP) in the sky, how can you determine your latitude
the altitude of the NCP is the same as your latitude
orion is visible on winter evenings in the northern hemisphere but not summer evenings because of
the location of earth in its orbit
why do we have season on earth?
as earth goes around the sun the earth’s axis remains pointed towards polaris, the northern and southern hemispheres alternately receive more and less sunlight
which of the following statements are true?
both the northern and southern hemispheres receive the same amount of sunlight on the equinoxes
boy he the northern and southern hemispheres receive the same amount of sunlight on the solstices
the northern hemispheres receives the most direct sunlight on the summer solstice
both A and C are true
why is it summer in the northern hemisphere when it is winter in the southern hemisphere?
the northern hemisphere is tilted toward the sun and receives more direct sunlight
which of the following statements ab constellations is false?
there are only 88 official constellations
some constellations can be seen from both the northern and southern hemispheres
some constellation can be seen in both the winter and summer
most constellations will be unrecognizable hundreds of years from now
most constellations will be unrecognizable hundreds of years from now
what causes precession of the Earth’s rotation axis?
the force of gravity from the sun and moon on the earths equatorial bulge
if the earth turns one full rotation in approx 24 hrs, how many degrees per hour does the sky turn?
15 deg/h
which of the following is equivalent to one 3,600 th of a degree?
second of arc
if the orbit of earth eccentricity increased to 0.65 what would happen to earths seasons?
they’d be more intense
which of the following locations are closer to the south celestial pole?
(RA= 14 h Declination= +88 degrees)
(RA= 14 h Declination= -88 degrees)
(RA= 23 h Declination= 2 degrees)
(RA= 18 h Declination= -66 degrees)
(RA= 14 h Declination= -88 degrees)
where is the north celestial pole in our sky for latitudes between 35-44 degrees N
35-45 degrees north
how often is the sun at zenith for an observer at the equator?
twice per year
if earths axis tilt was significantly greater than its current 23.5 degrees, but earth’s rotation period and orbital period were unchanged what would happen?
the length of each season (the number of days from the summer solstice to the fall equinox) would be significantly longer than it is now.
an observer in the northern hemisphere watches the sky for several hours. due to the motion of the earth, this observer notices that the stars near the north celestial pole appear to move. what pattern does this movement follow?
counter-clockwise around the celestial pole
which of the following describes a concept very similar to latitude?
declination
ecliptic
the other traced out by the sun in the sky over one year against the background stars
if the north celestial pole appears on your horizon, what is your latitude?
0 degrees S
if the north celestial pole appears on your zenith, what is your latitude
90 degrees N
where on earth would you be at if polaris was at your zenith?
the north pole
while watching a star you see it moves 45 degrees across the sky. how long have you been watching it?
3 hours
if you were standing at earths north pole, which of the following would be located at the zenith?
the nadir
the star vega
the celestial equator
the north celestial pole
the north celestial pole
how much of the night sky lies north of the celestial equator?
exactly half
how many stars can u see with your naked eye on a clear, moonless night from a dark location?
a few thousand
constellation
a region of the celestial sphere
which of the following best describes the big dipper?
an asterism
which of the following statements ab the celestial sphere is not true?
when we look in the sky, the stars all appear to be located on the celestial sphere
earth is placed at the centre of the celestial sphere
the celestial sphere does not exist physically
the “celestial sphere” is just another name for our universe
the “celestial sphere” is just another name for our universe
what is true about the celestial sphere at all latitudes?
it represents an extension of earth’s equator onto the celestial sphere
what do stars in the same constellation have in common?
they are in the same part of the sky as seen from the earth
how many arc seconds are in 1 degree
3,600
what is the magnitude scale?
can used to indicate the apparent intensity of a celestial object
what is the meridian?
a half-circle extending from your horizon due north, through your zenith, to your horizon due south
what aspect of an object depends on both size of the object and the distance to the object?
angular diameter
what is a circumpolar star?
a star that always remains above your horizon and appears to rotate around the celestial pole
what makes the north star, Polaris special?
it appears very near the north celestial pole
in 1054 CE, the Chinese recorded a very interesting and powerful cosmic event. what was the event?
a supernova
what did Eratosthenes measure very accurately?
the size of earth
who were the two great authorities of greek astronomy?
aristotle and ptolemy
whose writings became so famous that he was known throughout the middle east simply as “the philosopher”?
aristotle
which of the following statements reflects beliefs that were almost universally held in pre-Copernican astronomy?
the planets travelled in elliptical orbits around the earth
the planets travelled in elliptical orbits around the sun
the sun was the centre of the universe
the earth was at the centre of the universe
the earth was at the centre of the universe
in what circumstances is retrograde motion observable?
it is observable for planets more distant from the sun than the earth
you are observing the night sky from Mars. in what circumstances is retrograde motion observable?
it is observable for planets more distant from the sun than mars
what is the term for the apparent westward motion of a planet in the sky compared to the background stars
retrograde motion
what is parallax
the apparent motion of an object due to the motion of the observer
why did ancient astronomers believe the earth did not move?
because they could not detect parallax
what was the greatest inaccuracy in Copernicus’s model of the solar system?
that the planets travelled in circular orbits with uniform motion
which o father following objects cannot transit (i.e. pass in front of) the sun, as seen from jupiter?
saturn
what was Tycho Brahe’s greatest contribution to astronomy?
his 20 years of careful observations of the planets
what two numbers tell us the size and shape of an ellipse?
semi-major axis, eccentricity
the orbit of planet A had an eccentricity of 0.5 and the orbit of planet B has an eccentricity of 0.01. what can be said about the shape of the orbits of these two planets?
the orbit of planet A is more elongated than the orbit of planet B
which of the following masses exert higher gravitational force on each other?
M=2——————m=2
M=2——————m=1
M=2——————m=8
M=2——————m=8
which of the following masses exerts smaller gravitational force on each other?
M=2——————m=2
M=2——————m=1
M=2——————m=8
M=2——————m=1
given its orbital period of 76 years, what is the average distance of Comet Halley from the Sun?
18 AU
an object had been located orbiting the Sun at a distance of 65 AU. what is the approx orbital period of this object?
524 years
on average saturn is 10 AU from the sun. what is the approx orbital period of Saturn?
32 years
the orbit of the planet Jupiter is an ellipse with the sun at one focus. what is located at the other focus?
nothing
the orbit of the moon is an ellipse with the earth at one focus. what is located at the other focus?
nothing
a comet is found in a highly elliptical orbit with a semi-major axis equal to one AU. according to Kepler’s third law of planetary motion, what would the sidereal period of this comet be?
one year
gravitational force of the sun exerted on the earth is the same as…
the force exterted by the sun on the earth
an object moves in a straight line at a constant speed. which number of forces could not act on the object?
1
what does the orbital velocity of an object with respect to the distance does?
decreases
at which lunar phase(s) are the tides at their lowest?
both first quarter moon and third quarter moon
if mats rises approx the same time as a particular star. if mars is in normal prograde motion at what time Mars will rise next night?
later than the star
the spring tides occur during the new and full lunar phases
true
if the planet orbits the sun at a distance of 4 AU, then it’s orbital period is 8 years
true
asteroids in the asteroid belt in relation to mars and jupiter
asteroids closer to mars have shorter orbital periods than those closer to jupiter
what fraught of Ptolemy’s model of the universe made it possible to explain retrograde motion?
epicycles
a common feature of astronomy as practices worldwide prior to the Greeks
recognizing patterns
what was the reason for using epicycles and deferents to explain the motion of the planets in the night sky?
retrograde motion
why did ancient astronomers believe that the Earth did not move?
because they could not detect parallax
the term for a small circle that had its centre located on the circumference of another larger circle?
epicycle
the Copernican system was no more accurate than the Ptolemaic system in predicting the positions of the planets because of a key factor that was unchanged from the ptolemaic system. what was the factor?
the copernican system used uniform circular motion
what is the book “De Revolutionibus Orbium Coelestium” about?
it lays out the Copernican theory for the first time
