Deck 27: Stars and Galaxies

Question 1

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

A)About 3,000
B)About 30,000
C)About 300,000
D)About 3,000,000

Answer 1

A

Question 2

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.

Answer 2

A

Question 3

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

Answer 3

D

Question 4

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 5

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 6

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 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

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 9

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 10

Polaris is always directly overhead at

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

Question 11

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 12

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 13

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 14

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 15

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 16

The star nearest the Earth is

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

Question 17

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 18

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 19

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 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

The temperature of a star is evidenced by its

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

Question 22

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

Question 23

The longest living stars are those of

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

Question 24

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 25

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

A)Helium
B)Nitrogen
C)Carbon
D)Phosphorous

Question 26

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 27

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 28

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 29

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 30

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 31

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 32

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 33

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 34

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 35

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 36

Thermonuclear fusion occurs mainly in the

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

Question 37

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 38

The masses of stars are found by measurements of

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

Question 39

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 40

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 41

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 42

Metals are relatively more abundant in

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

Question 43

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 44

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 45

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 46

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 47

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 48

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 49

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 50

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 51

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 52

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

Question 53

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

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

Question 54

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

Question 55

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 56

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 57

The elements found on Earth have much to do with

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

Question 58

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 59

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 60

A white dwarf is a former

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

Question 61

An active galactic nucleus

A)is a place of intense star formation.
B)arises from the gigantic black hole at the center of a galaxy.
C)is a supermassive supergiant star that resides at the center of larger galaxies.
D)is a giant dust cloud at the center of a galaxy.

Question 62

The observable universe is

A)the minor portion of the universe we can observe.
B)the part of the universe that is within the visible electromagnetic spectrum.
C)part of the universe visible to the unaided eye.
D)about 100 billion light years across.

Question 63

Describe the fate of planet Earth if the Sun were to collapse to a black hole.

Question 64

How does the mass of a giant star compare with the mass of the black hole it may become? How do the densities compare?

Question 65

If the Sun collapsed to a black hole, the time required for the Earth to orbit the collapsed Sun would

A)increase.
B)decrease.
C)stay the same.

Question 66

Quasars are

A)ancient, extremely high energy galaxies believed to have formed in the early universe.
B)a conglomeration of pulsars within a galaxy.
C)a conglomeration of spiral galaxies.
D)white dwarfs that have undergone final collapse.

Question 67

If a star collapses to a tenth its size, gravitation at its surface increases by

A)ten.
B)twenty.
C)one hundred.
D)one thousand.
E)more than one thousand.

Question 68

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

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

Question 69

Our local group is composed of how many galaxies?

A)Less than 100
B)Less than 400
C)Less than 1,000
D)1,526

Question 70

When a star collapses to half size, the gravitational field at its surface

A)doubles.
B)quadruples.
C)increases eightfold.
D)remains constant.

Question 71

The Milky Way galaxy is

A)in the process of colliding with the Magellanic Cloud galaxies.
B)where Earth resides.
C)a spiral galaxy.
D)All of the above

Question 72

One of Edwin Hubble's discoveries is that the known universe is expanding. This means that

A)most all observable galaxies are moving away from each other.
B)light rays bend as they near the event horizon of a black hole.
C)light rays undergo acceleration as they travel vast distances.
D)the mass of the universe is slowly dissipating.

Question 73

A Starburst galaxy has this name because of its

A)high rate of star formation.
B)high rate of supernovae.
C)large number of pulsars.
D)large number of neutron stars.

Question 74

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 75

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 76

Galaxies are aggregations of stars, stellar dust, and gas. Their masses

A)are all about the same, which is huge.
B)vary greatly from one galaxy to the next.
C)are small compared to blue supergiant stars.
D)depend on the rate of pulsar emissions within them.

Question 77

Elliptical galaxies

A)tend to be smaller than the other types of galaxies.
B)have little in the way of dust and gas.
C)are thought to be former starburst galaxies.
D)All of the above

Question 78

As more and more mass falls into a black hole, the radius of its photon sphere

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

Question 79

As a star undergoes collapse, its rate of rotation

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

Question 80

A supercluster is a

A)cluster of galactic clusters.
B)very large local cluster.
C)local cluster with at least 10,000 supergiant stars.
D)local cluster with at least 500 supermassive black holes.