Deck 27: Stars and Galaxies

Question 1

Polaris is always directly overhead at

A)the north pole.
B)any location north of the equator.
C)the equator.

Answer 1

A

Question 2

What is the upper limit of stars the unaided eye can discern on a moonless night in a rural area?

A)about 3000
B)about 30,000
C)about 300,000
D)about 3,000,000

Answer 2

A

Question 3

Seasons here are Earth are a result of

A)the rotation of our planet about its axis.
B)the revolution of our planet around the Sun.
C)the movement of our planet within the Milky Way.
D)the tilt of Earth's axis.

Answer 3

D

Question 4

Summer and winter constellations are different because

A)of the spin of the Earth about its polar axis.
B)the night sky faces in opposite directions in summer and winter.
C)of the tilt of the Earth's polar axis.
D)the Earth is at the solar perigee in winter and apogee in summer.
E)the universe is symmetric.

Question 5

The changing shapes of constellations in the night sky is caused by

A)the rotation of our planet about its axis.
B)the revolution of our planet around the Sun.
C)the movement of our planet within the Milky Way.
D)the tilt of Earth's axis.

Question 6

The yearly motion of celestial objects in the sky is caused by

A)the rotation of our planet about its axis.
B)the revolution of our planet around the Sun.
C)the movement of our planet within the Milky Way.
D)the tilt of Earth's axis.

Question 7

The North Star has very little apparent rotation in the night sky because

A)it lies directly above the Earth's axis of spin.
B)it rotates in the same relative orbit as Earth.
C)its rate of spin directly matches Earth's.
D)the Oort cloud distorts the view of the naked eye.

Question 8

We do not see stars in the daytime because

A)the Sun blocks their view.
B)they simply don't exist in the daytime part of the sky.
C)skylight overwhelms starlight.
D)of the lack of contrast with moonlight.
E)the solar wind obscures their view.

Question 9

Which best describes the intrinsic motion of stars?

A)their circular motion across the sky in a 24-hour period
B)their apparent yearly cycle around the Sun,due to Earth's revolution
C)their motion relative to all other bodies
D)their motion relative to Earth

Question 10

In which city is Polaris highest in the sky?

A)Singapore
B)Mexico City
C)Denver
D)Anchorage
E)All the same,depending on the time of night

Question 11

The daily motion of celestial objects in the sky is caused by

A)the rotation of our planet about its axis.
B)the revolution of our planet around the Sun.
C)the movement of our planet within the Milky Way.
D)the tilt of Earth's axis.

Question 12

The star nearest the Earth is

A)the Sun.
B)Alpha Centauri.
C)Polaris.
D)the Moon.

Question 13

We say we are looking back in time when we are looking at the stars because

A)we see stars as they once were when their light reaches us.
B)space curves,we are actually looking at the past when we look in the night sky.
C)stars are emitting immense radiation,we are seeing processes that have already happened.
D)Earth's atmosphere bends and distorts their light.

Question 14

The nearest star system closest to our Sun is about

A)4 light years away.
B)20 light years away.
C)100 light years away.
D)40,000 light years away.

Question 15

A radio signal emitted from Earth would take about

A)4 years to leave our galaxy.
B)20,000 years to leave our galaxy.
C)80,000 years to leave our galaxy.
D)100,000 years to leave our galaxy.

Question 16

The Milky Way galaxy is about

A)4 light years in diameter.
B)40 light years in diameter.
C)100 light years in diameter.
D)100,000 light years in diameter.

Question 17

The background stars during a solar eclipse are those of constellations

A)of the opposite season.
B)seen in the nighttime sky.
C)not seen normally.
D)seen in the opposite hemisphere.

Question 18

A light year is a unit of

A)time.
B)energy.
C)distance.
D)mass.

Question 19

How far is a light year?

A)nearly 10 trillion km
B)the distance of one Earth orbit
C)300,000 km
D)All of the above

Question 20

The diurnal rotation of the stars refers to the

A)apparent rotation of the celestial sphere due to the rotation of the Earth.
B)movement of the stars across the sky during daytime hours.
C)rate of spin of stars in their formation stage.
D)particular constellations that are visible in different times of the year.

Question 21

Which star will emit the shortest wavelength of its peak frequency?

A)a blue star
B)a yellow star
C)a red star
D)a green star

Question 22

The temperature of a star is evidenced by its

A)brightness.
B)color.
C)angular momentum.
D)distance.
E)rate of burning.

Question 23

The event that changes a protostar to a full-fledged star is

A)gravitational collapse.
B)gravitational expansion.
C)thermonuclear fusion.
D)the emission of light.
E)a catastrophic increase in temperature.

Question 24

Luminosity is

A)the total amount of light energy that star emits into space.
B)the stars apparent brightness.
C)the stars particular color spectrum output.
D)the stars total infrared output.

Question 25

Thermonuclear fusion occurs mainly in the

A)cores of stars.
B)outer layers of stars.
C)both,actually

Question 26

What are the relative compositions of the materials from which stars form?

A)about 74% hydrogen,about 24% helium,no more than 2% other materials
B)about 24% hydrogen,about 74% helium,no more than 2% other materials
C)about 2% hydrogen,about 74% helium,no more than 24% other materials
D)Stars have vastly differing combinations of materials.

Question 27

On the H-R diagram our Sun is a

A)white dwarf.
B)star of average luminosity and temperature.
C)red supergiant.
D)relatively bright,blue star.

Question 28

A star's color tells us

A)how much energy a star produces.
B)its surface temperature.
C)its rotational speed.
D)both how much energy it produces and its surface temperature.

Question 29

Which is greater,the gravitational attraction between a newborn baby and the Earth,or the gravitational attraction between the Earth and all the planets of the solar system?

A)the attraction between the baby and Earth
B)the attraction between the planets and Earth
C)They are roughly equal.
D)The baby's and the planets gravitational attractions are inversely proportional to each other.

Question 30

The stars Procyon and Betelgeuse both appear equally bright to Earthbound viewers.Yet Betelgeuse emits 5000 times more light than Procyon.Why do they appear to be equally bright?

A)because Betelgeuse is much farther than Procyon
B)because Betelgeuse is undergoing fission,not fusion
C)because Betelgeuse lies in the same plane of Earth's orbit
D)because Procyon is superhot

Question 31

The masses of stars are found by measurements of

A)light intensity.
B)temperature.
C)Doppler shifting.
D)binaries.
E)relative sizes.

Question 32

Most white dwarfs

A)have relatively hot surfaces.
B)have relatively cool surfaces.
C)evolve into black holes.
D)are about as dense as their parent stars.

Question 33

What is the reference that astronomers use to denote the luminosity of stars?

A)the luminosity of the Sun
B)the luminosity of the Northern Star
C)the luminosity of Proxima Centauri,our solar system's closest neighbor star
D)the luminosity of the cluster of stars at the center of the Milky Way galaxy

Question 34

A star's luminosity tells us

A)how much energy a star produces.
B)its surface temperature.
C)its rotational speed.
D)both how much energy it produces and its surface temperature.

Question 35

The H-R Diagram,an important tool of astronomers,relates stellar temperature to stellar

A)distance.
B)mass.
C)color.
D)density.
E)luminosity.

Question 36

Stars to the lower left of the Hertzsprung-Russell diagram tend to be relatively

A)hot and blue.
B)long lasting.
C)huge and massive.
D)yellow and of average size.

Question 37

The longest living stars are those of

A)low mass.
B)high mass.
C)intermediate mass.

Question 38

Why does a star's color corresponds to its temperature?

A)Higher temperature means more energetic light,which is seen as higher frequencies.
B)Because of the light shifts that take place when star light interacts with the Earth's atmosphere
C)Because the core temperature averages with the surface temperature to create an overall color
D)Because the ultraviolet output of a star directly modifies the visible light spectrum the star is emitting

Question 39

What are the outward forces that act on a star? What are the inward forces? How do these compare?

Question 40

Red giant stars are

A)close to exhausting their supply of hydrogen.
B)have already exhausted their supply of hydrogen.
C)are close to exhausting their supply of helium.
D)have already exhausted their supply of helium.

Question 41

Stars to the upper right of the Hertzsprung-Russell diagram tend to be relatively

A)hot and blue.
B)long lasting.
C)huge.
D)yellow and of average size.

Question 42

Supernovae are one of the most extreme events in the known universe.They are caused by

A)the implosion of a white dwarf,which has run out of all its fuel.
B)a supermassive supergiant star undergoing a massive nuclear chain reaction.
C)the collapse of a supermassive supergiant star.
D)Any of the above.

Question 43

What prevents stars greater than about 100 times the Sun's mass from existing?

A)The rate of thermal expansion would overcome gravitational attraction leading to explosion.
B)The gravitational attraction would overcome the rate of thermal expansion leading to a black hole.
C)Fusion cannot take place at these higher mass levels.
D)The gaseous material of the universe is too widely dispersed to allow for the formation of stars of this mass.

Question 44

The determining factor in the stages a star will progress through from birth to death is its

A)mass.
B)temperature.
C)composition.
D)relative density.

Question 45

Why can't any star,no matter how massive,fuse elements heavier than iron?

A)because the nucleons within iron have the least mass possible
B)because elements heavier than iron have less average mass per nucleon
C)It could happen,we just have not yet observed a star massive enough to do this.
D)Actually,this occurs on a regular basis,which explains the great abundance of heavy elements.

Question 46

What do astronomers expect will be left at the center of our solar system once the Sun has gone through all its life stages?

A)a planet sized diamond
B)a red giant
C)a black hole
D)a wormhole

Question 47

Metals are relatively more abundant in

A)old stars.
B)new stars.
C)neither in particular

Question 48

A star's size stabilizes when

A)thermal pressure and gravitational attraction balance each other.
B)the star's gravitational attraction is balanced by the gravitational attraction to neighboring stars.
C)the star first ignites.
D)it reaches temperatures of about 3 million K.

Question 49

What will halt the collapsing Sun's core once its fuel has been exhausted?

A)the inability of electrons to enter into neighboring electrons quantum state
B)outward thermal pressure
C)random quantum fluctuations
D)the shift from fusion to fission nuclear reactions

Question 50

The gold in Uncle Harry's teeth fillings originated in

A)the deep interior of the Earth.
B)fusion processes that date back about 5.5 billion years.
C)the Big Bang.
D)stars that blew up eons ago.
E)Fort Knox.

Question 51

It is theorized that a pulsar only emits X-rays and visible light during its early history.What do you suppose is the basis of this theory?

A)As the pulsar's energy dissipates,the frequency of the energy it emits drops.
B)X-rays are likely the result of radioactive decay,which only can occur in a pulsar's early history.
C)X-rays and visible light are both part of the electromagnetic spectrum.
D)The pulsars high rate of spin produces a magnetic field that,over time,slows the pulsar down.

Question 52

Most of the energy during the collapse of the iron core of a supergiant star is released in the form of neutrinos-nearly massless subatomic particles that rarely interact with matter.So how is it they can blow away a stars outer shells?

A)Although they rarely interact with matter,the sheer number released during the collapse is enough to move most of the star's mass into surrounding space at incredibly high rates of speed.
B)By creating a massive magnetic field that convulses in on itself,ripping away the stars outer shells
C)When neutrinos exceed a certain speed,22,300 km/s,they interact with matter quite effectively.
D)By developing a temporary,but relatively strong positive charge

Question 53

How is a larger star like an SUV,while a smaller star like a fuel efficient hybrid vehicle?

A)The larger the star,the faster it burns fuel.
B)The larger the star,the more likely it is to explode.
C)The larger the star,the shorter its life span.
D)Larger stars have only one source of energy.

Question 54

What event will eventually move an average star off the main sequence of the H-R diagram?

A)running out of hydrogen,causing gravitational influx,resulting in core temperatures high enough to begin fusing helium
B)surface cooling due to hydrogen loss
C)solar wind storms
D)its drift through space due to the gravitational attraction of neighboring giant stars

Question 55

Because a white dwarf is no longer burning fuel,it is more accurately described as being a

A)stellar remnant.
B)failed star.
C)protostar.
D)black elf.

Question 56

What is generally the range of a star's hydrogen burning lifetime?

A)from a few million to 50 billion years
B)from a few hundred thousand to 20 billion years
C)from 20 billion to 100 billion years
D)from 2 billion to 15 billion years

Question 57

After our Sun burns its supply of hydrogen,it will become a

A)white dwarf.
B)black dwarf.
C)black hole.
D)red giant.
E)blue giant.

Question 58

What will be the predominant element within the Sun after it has died?

A)helium
B)nitrogen
C)carbon
D)phosphorous

Question 59

Why are elements heavier than iron less abundant than those that are lighter?

A)because the duration of a supernova is relatively short
B)because they tend to be unstable,and easily undergo fission
C)Spectral evidence suggests they are only rare here on Earth.
D)This is one of the mysteries of cosmic formation that has yet to be answered.

Question 60

Stars to the upper left of the Hertzsprung-Russell diagram tend to be relatively

A)hot and blue.
B)long lasting.
C)huge.
D)yellow and of average size.

Question 61

A main sequence star begins transforming into a red giant when

A)helium begins fusing.
B)helium within the core begins to expand.
C)contracting helium causes hydrogen to fuse.
D)hydrogen starts fusing within the core.

Question 62

Helium fusion within a star begins

A)after all the hydrogen within the star has been depleted.
B)when all carbon has been depleted.
C)because of the force of gravity.
D)with the expulsion of practically all hydrogen.

Question 63

Which is the earliest stage of a star?

A)Helium collects within the core.
B)Carbon collects within the core.
C)The surface of the star expands into a red giant.
D)The star contracts into a blue giant.

Question 64

A black hole is

A)an empty region of space with a huge gravitational field.
B)a small region that has the mass of many galaxies.
C)the remains of a giant collapsed star.

Question 65

A pulsar is likely a

A)throbbing star in its death throes.
B)black hole companion.
C)spinning neutron star.
D)binary star with a dark companion.

Question 66

A black hole has

A)about the same mass as the original star from which it formed.
B)infinite mass.
C)about half the mass of the star from which it formed.
D)a mass that widely fluctuates.

Question 67

If the Sun collapsed to become a black hole,the Earth's gravitational attraction to it would be

A)more.
B)less.
C)no different.

Question 68

The elements found on Earth have much to do with

A)white dwarfs.
B)neutron stars.
C)pulsars.
D)quasars.
E)supernovae.

Question 69

A white dwarf is a former

A)low-mass star.
B)high-mass star.
C)white giant.

Question 70

What determines if a star becomes a white dwarf,a neutron star,or a black hole?

A)the principal factor is mass
B)the principal factor is density
C)the principal factor is temperature
D)the principal factor is luminosity

Question 71

Compared to the event horizon,the photon sphere of a black hole is

A)nearer the singularity.
B)farther from the singularity.
C)at the same location.

Question 72

What happens to a star when the fusion cycle gets to the element iron?

Question 73

Which one of these elements is normally the remnant of a supernova?

A)hydrogen
B)helium
C)silver
D)none of these

Question 74

The event horizon of a black hole is

A)the surface below which no matter or energy can escape.
B)the surface where light becomes trapped in a circular orbit around the black hole.
C)the physical surface of the black hole.
D)the point in time when a black hole comes into being.

Question 75

Most of the atoms in the universe are thought to be

A)hydrogen.
B)helium.
C)about equal amounts of hydrogen and helium.
D)iron.
E)elements unknown at present.

Question 76

When a star collapses to become a black hole,its mass

A)increases.
B)decreases.
C)remains unchanged.

Question 77

A planetary nebula arises from

A)the remains of a solar atmosphere.
B)planetary accretion.
C)a black hole.
D)the gravitational attraction of interstellar dust.

Question 78

What event marks the birth of a star,and what event marks its death?

Question 79

A black hole is

A)a region of space that is collapsed in on itself.
B)the result of the collapse of supergiant star.
C)likely found at the center of each spiral galaxy.
D)All of the above

Question 80

Which is the latest stage of a star?

A)Helium collects within the core.
B)Carbon collects within the core.
C)The surface of the star expands into a red giant.
D)The star contracts into a blue giant.