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Astro 311 - Final

STUDY
PLAY
A nova includes...
Mass transfer into a white dwarf in a binary system
Most important property in how a star will evolve and die?
Mass
A white dwarf can explode when...
its mass exceeds the Chandreskhar limit
A type II supernova occurs when...
iron builds up in the core
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some examples of which type of dying star exhibit rapid pulses that were originally suspected to be communications from extraterrestrials?
Neutron Star
the average density of a neutron star approaches...
about 10^14 kg/m^-3
Pulsars show all of the following except...
high temp. fusion reactions
Lighthouse model explains
rotating neutron star generates observable beam of light
Many millisecond pulsars lie within
Globular clusters
Based on star counts, 100 years ago most astronomers thought galaxies were
circular disk, 10 kpc wide, 2 kpc thick
Location of the galactic center was first found by Harlow Shapley using
RR lyrae variables in globular clusters
Which is the correct description of the sun's location within the milky way?
above the disc, about 1/3 of the galactic radius from the center
Why was Herschel's strategy for mapping out galaxy flawed?
he relied on visual wavelengths, which are obscured by dust
Curtis was right in arguing the milky way was
similar to spiral nebulae, blocking our view of spiral nebula in the galactic plane
Harlow Shapely was correct in arguing the Milky Way was
much larger than previously expected
Region on the HR diagram where pulsating variables occur is called the
instability strip
All RR lyrae stars have about the same
luminosity (of about 100 suns)
Blank
Blank
A star in the instability strip of the HR diagram would
vary in temperature and radius
most of the new star formation in the Galaxy is found in the...
spiral arms
the orbits of Population II stars (older stars) have been compared to
comets around the sun
galactic year is the time for our solar system to orbit the galaxy; it is about...
225 million years
detailed measurements of the disk and central bulge region of our galaxy suggest our Milky Way is a...
barred spiral galaxy
The "aspect ratio" of thickness to width of the galactic disk is about
1:100
which sequence of formation by age is correct, oldest to youngest?
- open clusters, emission nebulae, globular clusters
globular clusters, emission nebulae, open clusters
What use are 21 cm radio waves to galactic astronomers?
their doppler shifts allow us to map the motions of the hydrogen in the galaxy
leading explanation for the existence of spiral arms are
passages of spiral density waves
Which of the following is most like the rotation of stars in the disk of the Milky Way?
Cars moving at a constant speed on a circular race track
What two observations allow us to calculate the Galaxy's mass?
sun's orbital velocity and its distance from the Galactic Centre
Which method relies on the mass of a dark object revealing its presence...
temporary brightening of a distant star by a gravity lens
most of the mass of the Milky Way seems to exist in the form of...
dark matter (out in the halo)
Proposed WIMPS would be massive like ______, but more elusive than __________, however this is not yet proven
neutrons, neutrinos
Leave blank
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A spherical galaxy, like M 87, which looks like a monster globular cluster, is type...
E0
Flattest of elliptical class are class...
E7
Which type of galaxy has a stellar disk, but without gas and dust?
S0 (Spiral Galaxy)
You see a spiral galaxy with a large central bulge and tightly wrapped arms. It would be a...
Spiral galaxy (Sa)
An intermediary wound barred spiral galaxy would, in Hubble's system, be...
SBb
Hubble's classification, which type of galaxy has a small bulge and loose, widely spread, poorly defined spiral pattern
Sc
In Hubble's classification, which type of galaxy has no stellar disk, no gas, and no dust?
Elliptical (E0)
Which statement is true about ages and masses of spiral and elliptical galaxies?
Both types are about the same age, but spirals vary less in mass
Which of these would be made up of only Population II stars?
elliptical galaxies
Most galaxies in the local group are...
small ellipticals like the companions to M31 in Andromeda
Most of the stars in the Local Group are in
big spirals like our galaxy (M31)
Within the boundaries of the constellations of Coma and Virgo are found...
largest nearby superclusters of galaxies
Why does the cepheid "standard candle" have limited usefulness beyond 20 mpc?
cepheids are too faint to be seen beyond that distance, even with HST
Which of the following paraphrases Hubble's Law?
the greater the distance to a galaxy, the greater the redshift
The Tully-Fisher relation is between the galaxy's luminosity and its....
rotation
For finding the distance to M31, Hubble relied upon...
cepheid variables in its spiral arms
While examining the spectrum of a galaxy you find that all the hydrogen lines are shifted to the longest wavelengths. The galaxy is...
moving away from us
Quasars usually have their distances measured by what technique?
Hubble's Law
Why do some quasars have red shifts greater than 1?
they are very distant, with relativistic red shifts that take into account dilation of space-time, as Einstein predicted
Quasars were at cosmological distance that appeared like ordinary faint stars meant that
they must be producing such large quantities of energy that even fusion could not explain
In active galaxies, their central engines may be temporarily fed by...
nearby galaxies
A billion solar mass black hole would still have a radius of only...
20 AU
Synchotron radiation produces a _______ spectrum
continuous non-thermal
The energy radiated by a typical quasar requires that its black hole accrete about
ten solar masses a year
When spiral galaxies do collide, the impact is greatest on their...
giant molecular clouds
due to the galaxy density and collisions, _______ are in the centres of clusters
spirals
Pre-galactic blobs had masses similar to...
Large Magellanic clouds
why are super massive galaxies often found at the cores of rich galaxy clusters?
they are the result of many galactic mergers; one galaxy growing at the expense of others
some quasars show absorption spectra with a smaller redshift than their emission spectra, this indicates that...
there is cooler gas between us and the quasar
Astronomers think most galaxy interaction took place at redshifts greater than 1 because...
clusters were more compact
why is thought that quasars probably spend only a fairly short time in their highly luminous place?
because a black hole cannot power a highly luminous quasar for more than a few million years
Energy radiated from a typical quasar requires that its black hole accrete about...
10 solar masses a year
The ratio of bulge mass to black hole mass is roughly...
200 to 1
What is the Great Wall?
large sheet of galaxies measuring 70 mpc by 100 mpc
Gravitational lensing of distant, faint irregular galaxies may be the key to...
mapping dark matter
Homogeneity and isotropy taken as assumptions regarding the structure and evolution of the universe, are known as...
cosmological principle
Hubble time is expressed as
1/H (13 Billion years?)
Redshift of galaxies is correctly interpreted as...
space itself is expanding with time, so the photons are stretched while they travel outside of space
What does Hubble Law imply about the universe?
the universe had a beginning and has expanded since, giving it a finite age
The sky is dark at night because...
all the light from the objects in space hasn't reached us yet
What is the Big Bang?
the event that started the expansion of the universe
If the density of the universe is greater than the critical density, this means that...
the universe is expanding at a rate less than the escape speed of the universe
In the closed universe model, the geometry of space time in two dimensions resembles the surface of a...
sphere
in Robert Frost's classic poem, when he ends with "ice will suffice", the universe is...
open
In a closed universe, a beam of light will...
come back to where it originated
Critical evidence for cosmic acceleration in 1998 came from two teams of astronomers, both observing...
type I supernovae
the universal accelerating force could not be considered...
dark matter
Matter made out of protons, neutrons, and electrons in the universe accounts for that percent of the total mass of the universe?
less than 4%
in the critical density universe now proposed, the ratio of dark energy to matter is about...
3 to 1
in our best current theory, the first quasars formed about...
13 billion years ago
According to the turn off points of the oldest globular clusters, they formed about...
12 billion years ago
Discovery of the cosmic microwave background was important because...
experimental verification of a prediction from the Big Bang Theory
What temp. has the Big Bang has cooled to by now?
just over 2.7 K
Photons from the microwave background have not interacted with matter since the universe was how old?
400,000 years old
of the normal elements around us, the Big Bang produced...
hydrogen and helium
at the end of the first 15 minutes, the mass ratio of H/He was about...
75/25
The scarcity of what isotope is a critical test of the density of the present cosmos?
deuterium
about how hot was the Big Bang when matter and energy "decoupled"?
3,000 K
What did the cosmic microwave background tell cosmologists about the early universe?
horizon problem in that the microwave background is too isotropic
the best answer to both the flatness and horizon problem is...
the inflationary epoch
which of these could be considered as "hot dark matter"?
neutrinos
MASTERING ASTRO - Most of the energy of the supernova is carried outward via a flood of...
A.) gamma rays
B.) protons
C.) neutrinos
D.) positrons
E.) helium nuclei
Neutrinos
A 20 solar mass star will stay on the main sequence for 10 million years, yet its iron core can exist for only a...
A.) century.
B.) year.
C.) week.
D.) month.
E.) day
day
As a star's evolution approaches the Type II supernova, we find...
A.) helium to carbon fusion takes at least 100 million K to start.
B.) the heavier the element, the higher the temperature to fuse it.
C.) photo disintegration of iron nuclei begins at 10 billion K to ignite the supernova.
D.) the heavier the element, the less time it takes to make it.
E.) All of the above
All of the above
Rank the following steps that lead to a Type I supernova event in order of when they occur from first to last.
-white dwarf at Chandrasekhar limit, accretion disk with growing white dwarf, carbon fusion begins throughout, detonation
accretion disk with growing white dwarf, white dwarf at Chandrasekhar limit, carbon fusion begins throughout, detonation
the radius of a white dwarf is determined by a balance between the inward force of gravity and the outward push of ________
A.) electron degeneracy pressure
B.) nova
C.) massive star supernova
D.) white dwarf limit (1.4 solar masses)
E.) accretion disk
F.) white dwarf supernova
electron degeneracy pressure
A(n) _________ occurs when hydrogen fusion ignites the surface of a white dwarf in a binary system
A.) electron degeneracy pressure
B.) nova
C.) massive star supernova
D.) white dwarf limit (1.4 solar masses)
E.) accretion disk
F.) white dwarf supernova
nova
A(n) ___________ occurs when fusion creates iron in the core of a star
A.) electron degeneracy pressure
B.) nova
C.) massive star supernova
D.) white dwarf limit (1.4 solar masses)
E.) accretion disk
F.) white dwarf supernova
massive star supernova
A(n) white dwarf in a close binary system will explode as a supernova if it gains enough mass to exceed the _________
A.) electron degeneracy pressure
B.) nova
C.) massive star supernova
D.) white dwarf limit (1.4 solar masses)
E.) accretion disk
F.) white dwarf supernova
white dwarf limit (1.4 solar masses)
A(n) _________ consists of hot, swirling gas captured by a white dwarf (or neutron star or black hole) from a binary companion star
A.) electron degeneracy pressure
B.) nova
C.) massive star supernova
D.) white dwarf limit (1.4 solar masses)
E.) accretion disk
F.) white dwarf supernova
accretion disk
A(n) ____________ can occur only in a binary system, and all such events are thought to have the same luminosity
A.) electron degeneracy pressure
B.) nova
C.) massive star supernova
D.) white dwarf limit (1.4 solar masses)
E.) accretion disk
F.) white dwarf supernova
white dwarf supernova
In a neutron star, the core is....
A.) electrons and protons packed so tightly they are in contact.
B.) made of compressed neutrons in contact with each other.
C.) primarily iron and silicon.
D.) constantly expanding and contracting.
E.) no longer rotating.
made of compressed neutrons in contact with each other
An object more massive than the sun, but roughly the size of a city, is a...
A.) white dwarf.
B.) brown dwarf.
C.) red dwarf.
D.) neutron star.
E.) supernova remnant.
neutron star
What would happen if mass is added to a 1.4 solar mass white dwarf?
-The star would erupt as a carbon detonation (type I) supernova.
-The star's radius would increase. -The star would immediately collapse into a black hole.
-The core would collapse as a type II supernova.
-The star would explode as a nova.
the star would erupt as a carbon detonation (type I) supernova
Which of these does not exist?
-a million solar mass black hole -a 6 solar mass black hole
-a 6.8 solar mass neutron star
-a 1.0 solar mass white dwarf
-a 0.06 solar mass brown dwarf
a 6.8 solar mass neutron star
the most rapidly "blinking" pulsars are those that...
-spin fastest.
-are oldest.
-are most massive.
-are hottest.
spin fastest
X-ray bursters are similar to novae, except the collapsed star is a neutron star, not a white dwarf.

True or False
True
Three terrestrial-sized planets in orbits of a fraction of an AU have been found near
Supernova 1987A.
a magnetar.
Cygnus X-1.
a millisecond pulsar.
a white dwarf.
a millisecond pulsar
What are X-ray bursters?
They are the central sources of energy for planetary nebulae.
They are neutron stars on which accreted matter builds up, then explodes in a violent nuclear explosion.
They are violent energy sources known to lie at the heart of the Milky Way and similar massive galaxies.
They are rapidly rotating black holes whose precession points their poles toward us on occasion.
They are very massive stars that explode as supernovae, emitting bursts of X- rays and gamma-rays in the process.
They are neutron stars on which accreted matter builds up, then explodes in a violent nuclear explosion.
Almost half of all known millisecond pulsars are found in what type of object?
open clusters
emission nebulae
giant molecular clouds
globular clusters
supernova remnants
globular clusters
To which of these phenomena are X-ray busters most similar?
hypernovae
novae
type II supernovae
type I supernovae
planetary nebulae
novae
Gamma-ray bursts are observed to occur...
approximately uniformly over the entire sky.
throughout the Milky Way Galaxy.
near pulsars.
mainly near the Sun.
approximately uniformly over the entire sky
A proposed explanation for gamma-ray bursters is
coalescence of a neutron star binary.
hypernova-making black holes and bi-polar jets.
collisions between two white dwarfs.
Both A and B are possible.
All three are possible.
Both A and B are possible
Rank these objects based on their diameter, from largest to smallest. (Note that the neutron star and black hole in this example have the same mass to make your comparison easier, but we generally expect black holes to have greater masses than neutron stars.)

Jupiter, one-solar-mass white dwarf, main-sequence star of spectral type A, a two-solar-mass neutron star, the event horizon of a two-solar-mass black hole, the moon
main-sequence star of spectral type A, Jupiter, one-solar-mass white dwarf, the moon, a two-solar-mass neutron star, the event horizon of a two-solar-mass black hole
Rank these objects based on their mass, from largest to smallest.

main-sequence star of spectral type M, a one solar mass white dwarf, typical black hole (formed in a supernova), typical neutron star, Jupiter, the Moon
typical black hole (formed in a supernova), typical neutron star, a one solar mass white dwarf, main-sequence star of spectral type M, Jupiter, the Moon
Listed following are several astronomical objects. Rank these objects based on their density, from highest to lowest.

- singularity of a black hole, main sequence star, typical neutron star, one solar mass white dwarf
singularity of a black hole, typical neutron star, one solar mass white dwarf, main sequence star
Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death for a White Dwarf

-in a binary system, it can explode as a supernova
-usually has a very strong magnetic field
-viewed from afar, time stops at its event horizon
-size defined by its Schwarzschild radius
-sometimes appears as a pulsar
-has a mass no greater than 1.4MSun
- typically about the size (diameter) of Earth
- supported by electron degeneracy pressure
in a binary system, it can explode as a supernova, has a mass no greater than 1.4MSun, typically about the size (diameter) of Earth, supported by electron degeneracy pressure
Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death for a Neutron Star
-in a binary system, it can explode as a supernova
-usually has a very strong magnetic field
-viewed from afar, time stops at its event horizon
-size defined by its Schwarzschild radius
-sometimes appears as a pulsar
-has a mass no greater than 1.4MSun
- typically about the size (diameter) of Earth
- supported by electron degeneracy pressure
sometimes appears as a pulsar, usually has a very strong magnetic field
Listed following are distinguishing characteristics of different end states of stars. Match these to the appropriate consequence of stellar death for a Black Hole
-in a binary system, it can explode as a supernova
-usually has a very strong magnetic field
-viewed from afar, time stops at its event horizon
-size defined by its Schwarzschild radius
-sometimes appears as a pulsar
-has a mass no greater than 1.4MSun
- typically about the size (diameter) of Earth
- supported by electron degeneracy pressure
viewed from afar, time stops at its event horizon, size defined by its Schwarzschild radius
Black holes result from stars having initial masses
- less than the mass of the Sun.
- between 1 and 2 times the mass of the Sun.
- up to 8 times the mass of the Sun.
- more than 25 times the mass of the Sun.
more than 25 times the mass of the Sun.
When another spaceship is moving by you (at constant velocity), you will measure the spaceship to be shorter than its rest length, while passengers on that ship will measure your length to be shorter. Imagine that you and the passengers on the other ship are arguing (by radio) about who really is the one that has become shorter. To settle the argument, you agree to meet up on Mars and put the two spaceships next to each other to see which one is really shorter. What will you find when you meet up on Mars?
Your spaceship really is shorter than the other one.
Both spaceships are the same length.
The other spaceship really is shorter than yours.
Both spaceships are the same length
The figures below show several different astronomical objects. Rank the objects based on the strength of the gravitational force that would be felt by a spacecraft traveling at a distance of 10 AU from the center of each of the objects, from weakest to strongest.
- the sun, black hole mass, red giant mass, white dwarf mass
all the same
The figures below show several different astronomical objects. Rank the objects based on the amount that spacetime is curved (relative to flat spacetime) at a distance of 10 AU from the center of each of the objects, from least to greatest. If two (or more) cases are equal, show this equality by dragging one figure on top of the other(s).
- the sun, black hole mass, red giant mass, white dwarf mass
all the same
The figures below show several different astronomical objects. Rank the objects based on the amount that spacetime is curved (relative to flat spacetime) very near the surface (or event horizon) of the objects, from least to greatest.
- the sun, black hole mass, red giant mass, white dwarf mass
red giant mass, the sun, white dwarf mass, black hole mass
The figures below show several different astronomical objects. Rank the objects based on the acceleration a spaceship would have as it passed very near the surface (or event horizon) of each object, from smallest to largest.
- the sun, black hole mass, red giant mass, white dwarf mass
red giant mass, the sun, white dwarf mass, black hole mass
Where does an object on an elliptical orbit experience the greatest acceleration?
where spacetime has the most curvature
where spacetime has the least curvature
The acceleration is the same everywhere along the orbit.
where spacetime has the most curvature
Imagine that the Sun could be turned into a black hole without changing its mass. How would Earth's orbit change?
Earth's orbit would change from elliptical to unbound.
Earth's orbit would move farther from the Sun.
Earth would be sucked into the black hole.
Earth's orbit would not change.
Earth's orbit would not change.
Imagine that the Sun gained mass without changing its radius. How would the structure of spacetime change at the distance of Earth's orbit?
The structure of spacetime would stay the same.
Spacetime would become more curved at Earth's orbit.
Spacetime would become flatter (less curved) at Earth's orbit.
A black hole would engulf the Earth.
Spacetime would become more curved at Earth's orbit.
Listed following are several locations in the Milky Way Galaxy. Rank these locations based on their distance from the center of the Milky Way Galaxy, from farthest to closest.
- the edge of the central bulge, a cloud of gas and dust in the outskirts of the disk, our solar system, a globular cluster int he outskirts of the halo
a globular cluster in the outskirts of the halo, a cloud of gas and dust in the outskirts of the disk, our solar system, the edge of the central bulge
Imagine a photon of light traveling the different paths in the Milky Way described in the following list. Rank the paths based on how much time the photon takes to complete each journey, from longest to shortest. (USE NUMBERS)
- 1.) across the diameter of the galactic disk, 2.) from the sun to the center of the galaxy, 3.) through the disk from top to bottom, 4.) across the diameter of the central bulge, 5.) across the diameter of the galactic halo
5, 1, 2, 4, 3
Each item below belongs either with the population of disk stars or the population of halo stars of the Milky Way Galaxy. Match each item to the appropriate population (for Disk Stars (Yellow))
- youngest stars, stars whose orbits can be inclined at any angle, globular clusters, stars with the smallest abundance of heavy elements, stars that all orbit in nearly the same plane, the sun, oldest stars, high mass stars
youngest stars, the sun, stars that all orbit in nearly the same plane, high mass stars
Each item below belongs either with the population of disk stars or the population of halo stars of the Milky Way Galaxy. Match each item to the appropriate population (for Halo Stars (Green)) (USE NUMBERS)
- 1.) youngest stars, 2.) stars whose orbits can be inclined at any angle, 3.) globular clusters, 4.) stars with the smallest abundance of heavy elements, 5.) stars that all orbit in nearly the same plane, 7.) the sun, 8.) oldest stars, 9.) high mass stars
8, 3, 4, 2
The circular but relatively flat portion of the galaxy is the ________
- halo
- bulge
- disk
- spiral arm
- spiral galaxy
- globular cluster
disk
The first portion of the galaxy to form was the _______
- halo
- bulge
- disk
- spiral arm
- spiral galaxy
- globular cluster
halo
A tightly packed group of a few hundred thousand very old stars is a _________
- halo
- bulge
- disk
- spiral arm
- spiral galaxy
- globular cluster
globular cluster
A _________ stands out in a photo of a galaxy because it shines bright with light from massive young stars and glowing clouds of gas and dust
- halo
- bulge
- disk
- spiral arm
- spiral galaxy
- globular cluster
spiral arm
Our Milky Way galaxy is a _________
- halo
- bulge
- disk
- spiral arm
- spiral galaxy
- globular cluster
spiral galaxy
Stars orbiting in the ________ near the galaxy's center can have orbits highly inclined to the galactic plane
bulge
The first stars that formed in the Milky Way now...
orbit in the Galactic plane.
orbit closest to the Galactic center.
orbit in the same direction as the Milky Way spins.
have random orbits in the halo.
have random orbits in the halo
Population I stars came billions of years before Population II stars.
True
False
False
In our vicinity, the galactic disk is about 100 times wider than it is thick.
True
False
True
Most of the new star formation in the Galaxy is found in the...
spiral arms.
halo.
globular clusters.
galactic center.
bulge.
spiral arms
Matter belonging to the Galaxy can be traced out to ________ from the center.
50 kpc
5 kpc
8 kpc
15 kpc
200 kpc
50 kpc
The orbits of Population II stars have been compared to...
binary stars.
planets around the Sun.
comets around the Sun.
satellites around planets.
the accretion disc around a black hole.
comets around the sun
From the Sun, the distance to the Galactic Center is about
8 pc.
8,000 pc.
100,000 pc.
225 million pc.
100 billion pc.
8,000 pc
The Galactic Year is the time for our solar system to orbit the Galaxy; it is about
15 million years.
225 million years.
4.5 billion years.
9.6 billion years.
13.5 billion years.
225 million years
From Earth, the view of the Milky Way is a thin band of stars across the night sky. The part of the Milky Way galaxy that is described here is the...
globular cluster.
bulge.
halo.
disk.
spiral arm.
disk
Where are large dust clouds predominantly located in the galaxy M51?
distributed evenly throughout the galaxy
within or on the edges of the spiral arms
in the central bulge of the galaxy
in the wide spaces between the spiral arms
within or on the edges of the spiral arms
Where are the ionization nebulae predominantly located in the galaxy M51?
distributed evenly throughout the galaxy
within or on the edges of the spiral arms of the galaxy
in the central bulge of the galaxy
in the wide spaces between the spiral arms
within or on the edges of the spiral arms of the galaxy
Why are the ionization nebulae so bright?
They are the remains of stars that have died in supernova explosions.
They become very hot because of collisions with dust clouds.
They are always located very near a galaxy's hot core.
They are regions where gas is ionized by hot, young stars.
They are regions where gas is ionized by hot young stars
The figures below show several different astronomical objects. Rank the objects based on the amount that spacetime is curved (relative to flat spacetime) very near the surface (or event horizon) of each of the objects, from least to greatest.
- neutron star, main sequence star, red giant, white dwarf, black hole
red giant, main sequence star, white dwarf, neutron star, black hole
A telescope searching for newly formed stars would make the most discoveries if it were pointed...
between spiral arms.
within a spiral arm.
directly away from the Galactic center.
perpendicular to the Galactic disk.
within a spiral arm
The figures below show the same astronomical objects as shown in Part A. Rank the objects based on the amount that each would deflect the path of a photon of light from a very distant galaxy (as viewed from Earth), assuming the photon passes very near the surface (or event horizon) of each object, from smallest to largest.
- neutron star, main sequence star, red giant, white dwarf, black hole
red giant, main sequence star, white dwarf, neutron star, black hole
Astronomers observe galaxies and categorize them according to four different kinds of shapes: elliptical, spiral, barred-spiral, and irregular. In addition to shape, each of the four different galaxy types can be described by other common characteristics. Match the following characteristics with their corresponding galaxy type. (Elliptical Galaxy - E)
- elongated central structure flattened disk, spiral arms, gas and dust, young stars
- central bulge, flattened disk, spiral arms, gas, dust, young stars
- round, no disk, very little gas and dust, only old stars
- asymmetric, often with gas and dust, and young stars
round, no disk, very little gas and dust, only old stars
Astronomers observe galaxies and categorize them according to four different kinds of shapes: elliptical, spiral, barred-spiral, and irregular. In addition to shape, each of the four different galaxy types can be described by other common characteristics. Match the following characteristics with their corresponding galaxy type. (Spiral Galaxy - S)
- elongated central structure flattened disk, spiral arms, gas and dust, young stars
- central bulge, flattened disk, spiral arms, gas, dust, young stars
- round, no disk, very little gas and dust, only old stars
- asymmetric, often with gas and dust, and young stars
central bulge, flattened disk, spiral arms, gas, dust, young stars
Astronomers observe galaxies and categorize them according to four different kinds of shapes: elliptical, spiral, barred-spiral, and irregular. In addition to shape, each of the four different galaxy types can be described by other common characteristics. Match the following characteristics with their corresponding galaxy type. (Barred Spiral Galaxy - SB)
- elongated central structure flattened disk, spiral arms, gas and dust, young stars
- central bulge, flattened disk, spiral arms, gas, dust, young stars
- round, no disk, very little gas and dust, only old stars
- asymmetric, often with gas and dust, and young stars
elongated central structure flattened disk, spiral arms, gas and dust, young stars
Astronomers observe galaxies and categorize them according to four different kinds of shapes: elliptical, spiral, barred-spiral, and irregular. In addition to shape, each of the four different galaxy types can be described by other common characteristics. Match the following characteristics with their corresponding galaxy type. (Irregular galaxy - Irr)
- elongated central structure flattened disk, spiral arms, gas and dust, young stars
- central bulge, flattened disk, spiral arms, gas, dust, young stars
- round, no disk, very little gas and dust, only old stars
- asymmetric, often with gas and dust, and young stars
asymmetric, often with gas and dust, and young stars
The irregular classification is in some ways a method of dealing with galaxies that are clearly not elliptical or spiral in shape. Select the properties associated with irregular galaxies.
They have tightly wound spiral arms.
They all have centrally concentrated starlight.
They are typically smaller than spiral galaxies.
They exhibit vigorous star-forming activity.
Some show evidence for prior collision or close encounter with another galaxy.
They are rare.
They are typically smaller than spiral galaxies, they exhibit vigorous star-forming activity, some show evidence for prior collision or close encounter with another galaxy.
Since the time of Hubble, astronomers have learned that the blue color observed in some galaxies is the result of recent star formation. This interpretation has been confirmed by multiwavelength observations that have revealed the presence of star-forming gas clouds in galaxies hosting newly formed O-and B-type stars. Sort the galaxy types according to their level of star-forming activity. (for Galaxies with little Star forming activity)

-elliptical galaxies, spiral galaxies, barred spiral galaxies, irregular galaxies
elliptical galaxies
Since the time of Hubble, astronomers have learned that the blue color observed in some galaxies is the result of recent star formation. This interpretation has been confirmed by multiwavelength observations that have revealed the presence of star-forming gas clouds in galaxies hosting newly formed O-and B-type stars. Sort the galaxy types according to their level of star-forming activity. (for Galaxies with greater Star forming activity)

-elliptical galaxies, spiral galaxies, barred spiral galaxies, irregular galaxies
spiral galaxies, barred spiral galaxies, irregular galaxies
The following figures give the approximate distances of five galaxies from Earth. Rank the galaxies based on the speed with which each should be moving away from Earth due to the expansion of the universe, from fastest to slowest.
- 2 billion light years, 800 million light years, 5 billion light years, 230 million light years, 70 million light years
5 billion light years, 2 billion light years, 800 million light years, 230 million light years, 70 million light years
The following figures give the approximate speeds at which five galaxies are moving away from Earth due to the expansion of the universe. Rank the galaxies based on their distance from Earth, from farthest to closest.

- 130,000 km/s, 18,730 km/s, 1,577 km/s, 45,000 km/s, 5264 km/s
130,000 km/s, 45,000 km/s, 18,730 km/s, 5,264 km/s, 1,577 km/s
The following figures give the approximate speeds at which five galaxies are moving away from Earth due to the expansion of the universe. Rank the galaxies based on the amount of redshift that would be observed in each galaxy's spectrum, from largest to smallest.

- 130,000 km/s, 18,730 km/s, 1,577 km/s, 45,000 km/s, 5264 km/s
130,000 km/s, 45,000 km/s, 18,730 km/s, 5,264 km/s, 1,577 km/s
The graph shows that galaxies with high speeds as measured from Earth are __________.
moving away from Earth and are farther from Earth than galaxies with lower speeds
moving toward Earth and are farther from Earth than galaxies with lower speeds
moving away from Earth and are closer to Earth than galaxies with lower speeds
moving toward Earth and are closer to Earth than galaxies with lower speeds
moving away from Earth and are farther from Earth than galaxies with lower speeds
By looking at the graph, what can we say about the galaxies that have the lowest speeds?
They are moving away from Earth and are farther from Earth than galaxies with high speeds.
They are moving toward Earth and are farther from Earth than galaxies with high speeds.
They are moving away from Earth and are closer to Earth than galaxies with high speeds.
They are moving toward Earth and are closer to Earth than galaxies with high speeds.
They are moving away from Earth and are closer to Earth than galaxies with high speeds
Suppose that galaxy B is twice as far from Earth as galaxy A. Hubble's law predicts that galaxy B will be moving away from Earth with approximately _____.
the same velocity as galaxy A
four times the velocity of galaxy A
half the velocity of galaxy A
twice the velocity of galaxy A
twice the velocity of galaxy A
Imagine that when we looked out into the universe we found that the light from all galaxies was blueshifted (rather than redshifted) and that the light from the most distant galaxies was blueshifted by the greatest amount. Which statement best describes what we would conclude about the motions of galaxies in this case?
All are moving toward Earth, with nearby galaxies moving faster than distant galaxies.
All are moving toward Earth, with distant galaxies moving faster than nearby galaxies.
All are moving away from Earth, with nearby galaxies moving faster than distant galaxies.
All are moving away from Earth, with distant galaxies moving faster than nearby galaxies.
All are moving toward Earth, with distant galaxies moving faster than nearby galaxies.
The age of the universe is related to the slope of the graph of Hubble's law, and current data put the age of the universe at about 14 billion years. Suppose that future observations showed that the slope of Hubble's law on the graph is actually steeper than that shown. In that case, the age of the universe would be _________ than 14 billion years because the universe is expanding ______ than current data suggest. (Each choice gives words to fill in the two blanks, separated by a slash.)
younger / more rapidly
younger / more slowly
older / more rapidly
older / more slowly
younger / more rapidly
Our entire solar system orbits around the center of the ______ about once every 230 million years
- milky way galaxy
- local group
- rotates
- orbits
- universe
- solar system
milky way galaxy
The Milky Way and Andromeda galaxies are among a few dozen galaxies that make up our _______
- milky way galaxy
- local group
- rotates
- orbits
- universe
- solar system
local group
The sun appears to rise and set in our sky because Earth ______ once each day
- milky way galaxy
- local group
- rotates
- orbits
- universe
- solar system
rotates
You are one year older each time Earth ______ about the Sun
- milky way galaxy
- local group
- rotates
- orbits
- universe
- solar system
orbits
On average, galaxies are getting farther apart with time, which is why we say our ________ is expanding
- milky way galaxy
- local group
- rotates
- orbits
- universe
- solar system
universe
Our ________ is moving toward the star Vega at about 70,000 km/hr
- milky way galaxy
- local group
- rotates
- orbits
- universe
- solar system
solar system
Why do astronomers hypothesize that a massive black hole lies at the center of M 87?
Historical records show that a supermassive star at the center of M 87 exploded as a supernova, leaving behind a black hole.
Time-lapse images from space telescopes show stars falling to the center of M 87 and then disappearing from view.
Images of M 87 made with powerful telescopes show a well-defined black region devoid of any stars.
A very small region at the center of M 87 releases an enormous amount of energy.
A very small region at the center of M 87 releases an enormous amount of energy
The third image in the interactive photo (with the most detailed view of the galactic center) is labeled "gas disk." Which of the following best describes what we are seeing in this photo?
The bright central region is the bulge of the galaxy, and around it we see spiral arms.
The bright central region is a place where many young stars are being born, and the surrounding material is the gas from which these stars are made.
The black background in this photo is the supermassive black hole, and we see bright spots on top of it where nearby gas is emitting light.
The black hole is located deep within the bright central region, and around this region we see gas that is orbiting the central black hole.
The black hole is located deep within the bright central region, and around this region we see gas that is orbiting the central black hole.
Assuming that the bright core of M 87 is powered by a supermassive black hole, which of the following best describes the source of energy that makes the core appear so bright?
The black hole emits intense light as its huge mass is squeezed to infinite density at the black hole's singularity.
Gravitational potential energy is converted to thermal energy as matter from the surrounding gas disk spirals into the central black hole.
The immense gravitational force exerted by the central black hole in M 87 triggers nearby stars to explode as supernovae.
Gas and dust clouds form stars at a rapid rate due to forces from the central black hole in M 87.
Gravitational potential energy is converted to thermal energy as matter from the surrounding gas disk spirals into the central black hole.
The most successful model for explaining nuclear activity in galaxies involves a supermassive black hole that is gravitationally accreting matter from its surroundings. According to this model, different regions of the active galactic nucleus produce different types of radiation. Referring to the figure, match the region with the type of radiation being emitted. (Dusty Donut)
- infrared, none, x-ray, radio
infrared
The most successful model for explaining nuclear activity in galaxies involves a supermassive black hole that is gravitationally accreting matter from its surroundings. According to this model, different regions of the active galactic nucleus produce different types of radiation. Referring to the figure, match the region with the type of radiation being emitted. (Supermassive black hole)
- infrared, none, x-ray, radio
none
The most successful model for explaining nuclear activity in galaxies involves a supermassive black hole that is gravitationally accreting matter from its surroundings. According to this model, different regions of the active galactic nucleus produce different types of radiation. Referring to the figure, match the region with the type of radiation being emitted. (Accretion Disk)
- infrared, none, x-ray, radio
X-ray
The most successful model for explaining nuclear activity in galaxies involves a supermassive black hole that is gravitationally accreting matter from its surroundings. According to this model, different regions of the active galactic nucleus produce different types of radiation. Referring to the figure, match the region with the type of radiation being emitted. (Magnetized Jet)
- infrared, none, x-ray, radio
radio
Identify which emission properties relate to thermal and synchrotron (nonthermal) radiation (Thermal)
- radiation peaks at a characteristic frequency, radiation is consistently stronger at lower frequency (longer wavelengths), radiation depends on the temperature of the source, radiation depends on the presence of magnetic fields
radiation peaks at a characteristic frequency, radiation depends on the temperature of the source
Identify which emission properties relate to thermal and synchrotron (nonthermal) radiation (Synchrotron)
- radiation peaks at a characteristic frequency, radiation is consistently stronger at lower frequency (longer wavelengths), radiation depends on the temperature of the source, radiation depends on the presence of magnetic fields
radiation is consistently stronger at lower frequency (longer wavelength), radiation depends on the presence of magnetic fields
What conclusions can be drawn about the nature of the galaxy cluster's mass? (more than one)

Most of the cluster's mass is accounted for by the hot intracluster gas.
Most of the cluster's mass cannot be seen as visible matter.
Most of the cluster's mass is accounted for by the individual galaxies.
The mass of the dark matter accounts for more of the gravitational force within the cluster than does the mass of the visible matter.
Most of the cluster's mass cannot be seen as visible matter, The mass of the dark matter accounts for more of the gravitational force within the cluster than does the mass of the visible matter.
Rank the following items according to their size (diameter) from left to right, from largest to smallest.
- our solar system, milky way galaxy, the sun, jupiter, local group, the universe, the local supercluster, earth
the universe, local supercluster, local group, the milky way galaxy, our solar system, the sun, jupiter, earth
Rank the following items that describe distances from longest distance (left) to shortest distance (right) (USE NUMBERS)
- 1.) the distance from the Sun to the center of the galaxy, 2.) one light year, 3.) the distance across our solar system (to neptune), 4.) one astronomical unit (AU), 5.) distance from milky way galaxy to andromeda galaxy, 6.) distance from earth to alpha centauri, 7.) the average distance from earth to the sun
5, 1, 6, 2, 3, (4 and 7)
Some of the objects listed following are generally considered to be single (individual) astronomical objects; others are thought of as collections of many individual astronomical objects. Match these to the appropriate category. (Single astronomical objects)
- solar system
- milky way galaxy
- comet
- planet
- galaxy
- supercluster
- star
star, comet, planet
Some of the objects listed following are generally considered to be single (individual) astronomical objects; others are thought of as collections of many individual astronomical objects. Match these to the appropriate category. (Many astronomical objects)
- solar system
- milky way galaxy
- comet
- planet
- galaxy
- supercluster
- star
solar system, galaxy, milky way galaxy, supercluster
What do astronomers believe is the result of a merger between two spiral galaxies?
A Seyfert galaxy
A radio galaxy
An elliptical galaxy
A quasar
An even larger spiral galaxy
an elliptical galaxy
A head-tail radio galaxy is one that has ______ significantly while ejecting its radio lobes.
varied in brightness
dimmed
moved
rotated
brightened
moved
What is the defining characteristic of starburst galaxies?
They have a large number of young stars.
They are surrounded by globular clusters.
They have an overabundance of white dwarf and red dwarf stars.
They have a smooth, elliptical shape that is steadily expanding.
They are all much larger than the Milky Way
they have a large number of young stars
Intracluster gas has been observed in what region of the spectrum?
X-ray
Radio
Infrared
Visible
Ultraviolet
x-ray
Which galaxies are relatively rare in regions of high galaxy density?
Irregular
Giant elliptical
Spiral
Elliptical
Dwarf elliptical
spiral
How many years ago did most quasars became inactive?
5 billion
10 million
13 billion
10 billion
Quasars are still active.
10 billion
What is the average distance between adjacent galaxies in a galactic cluster?
A few million parsecs
A few hundred parsecs
A few parsecs
A few hundred thousand parsecs
A few billion parsecs
a few hundred thousand parsecs
Which law is used in the calculation of the combined galaxy masses of a binary galaxy system?
Hubble's law
Wien's law
Newton's form of Kepler's third law
Newton's first law
Newton's form of Kepler's third law
What is unusual about the results of mass determinations of clusters of galaxies?
The central galaxy in a cluster appears to contain 90 percent of the cluster's mass.
The calculations give wrong results unless general relativity is used.
The laws of Newtonian mechanics do not seem to work.
There is much more mass than can be accounted for by the visible galaxies.
there is much more mass than can be accounted for by the visible galaxies
What effect is thought to be due to the presence of dark matter around spiral galaxies?
Jets of energy appear to shoot up along the rotational axes of large galaxies.
High star-formation rates occur in interacting galaxies.
All galaxies with positive redshifts appear to be losing material.
The rotation rates of spiral galaxies and orbital interactions among galaxies within clusters suggest the presence of extra mass around them.
Elliptical galaxies have no Cepheid variable stars.
The rotation rates of spiral galaxies and orbital interactions among galaxies within clusters suggest the presence of extra mass around them
What is the best description of the distribution of the galaxies that lie within about 200 Mpc of Earth?
The galaxies are arranged in clusters that are randomly scattered throughout the universe.
The galaxies show up at random positions throughout the universe.
The galaxies seem to be arranged on the points of a grid.
The galaxies appear to be clustered into small spherical regions.
The galaxies appear to be arranged in a network of filaments, or strings, surrounding large, empty regions of space known as voids.
the galaxies appear to be arranged in a network of filaments, or strings, surrounding large, empty regions of space known as voids
What is the explanation of the low-redshift absorption lines in the spectra of quasars?
Slow-moving gases surrounding the quasar
High-velocity gas ejected toward us
High-velocity gases in the galaxy of which the quasar is a part
Intervening gas much closer than the quasar
intervening gas much closer than the quasar
What is the estimated percentage of dark matter in the universe?
1 percent
90 percent
99.9 percent
10 percent
90 percent
How did large galaxies form?
From the collisions and mergers of smaller galaxies
From the fragmentation of very large clouds of gas
From very large clouds of gas, much like the smaller galaxies
By very slowly accreting gas from the surrounding space
from the collisions and mergers of smaller galaxies
Galaxies sometimes interact at a distance, becoming distorted or changing shapes. Typically, how long does such an encounter take?
10 million years
Up to 10,000 years
Several hundred million years
3-5 billion years
several hundred million years
Shown following are several times in the history of the universe. Rank these times from left to right based on the average temperature of the universe at each time, from coolest to hottest.
- 100 million years after the Big Bang, today, 1.5 billion years after the Big Bang, 500,000 years after the Big Bang, 1 million years after the Big Bang
today, 1.5 billion years after the big bang, 100 million years after the big bang, 1 million years after the big bang, 500,000 years after the big bang
Shown following are several times in the history of the universe. Rank these times from left to right based on the peak wavelength in the spectrum of the cosmic microwave background, from shortest to longest.
- 100 million years after the Big Bang, today, 1.5 billion years after the Big Bang, 500,000 years after the Big Bang, 1 million years after the Big Bang
500,000 years after the Big Bang, 1 million years after the Big Bang, 100 million years after the Big Bang, 1.5 billion years after the Big Bang, today
Shown following are several times in the history of the universe. Imagine that you were able to watch a single photon that has been part of the cosmic microwave background since it first became present in the universe. Rank these times from left to right based on the wavelength this photon would have at each time, from shortest to longest.
- 1.) 100 million years after the Big Bang, 2.) today, 3.) 1.5 billion years after the Big Bang, 4.) 500,000 years after the Big Bang, 5.) 1 million years after the Big Bang
4, 5, 1, 3, 2
Leave blank
blank
Classify the given types of matter as either baryonic (meaning ordinary matter that contains protons and neutrons) or as nonbaryonic (meaning "extraordinary" matter that consists of more exotic subatomic particles). (for Baryonic matter)(USE NUMBERS)
- 1.) matter in stars, 2.) matter in brown dwarfs, 3.) dark matter consisting of weakly interacting subatomic particles, 4.) matter that probably makes up the majority of dark matter, 5.) matter in our bodies, 6.) dark matter consisting of Jupiter-size objects in galactic halos
1, 2, 5, 6
Classify the given types of matter as either baryonic (meaning ordinary matter that contains protons and neutrons) or as nonbaryonic (meaning "extraordinary" matter that consists of more exotic subatomic particles). (for nonbaryonic matter)(USE NUMBERS)
- 1.) matter in stars, 2.) matter in brown dwarfs, 3.) dark matter consisting of weakly interacting subatomic particles, 4.) matter that probably makes up the majority of dark matter, 5.) matter in our bodies, 6.) dark matter consisting of Jupiter-size objects in galactic halos
3, 4
Listed following are events that occurred either before or after the first five minutes in the history of the universe. Match these events to the appropriate time period. (Within first 5 minutes) (USE NUMBERS)
- 1.) galaxies formed, 2.) carbon nuclei formed by fusion, 3.) temperature fell to 10^15 K, 4.) inflation occurred, 5.) antielectrons (positrons) as common as electrons, 6.) strong force and electroweak force first became distinct, 7.) photons of cosmic microwave background released
3, 4, 5, 6
Listed following are events that occurred either before or after the first five minutes in the history of the universe. Match these events to the appropriate time period. (Sometime after the first 5 minutes) (USE NUMBERS)
- 1.) galaxies formed, 2.) carbon nuclei formed by fusion, 3.) temperature fell to 10^15 K, 4.) inflation occurred, 5.) antielectrons (positrons) as common as electrons, 6.) strong force and electroweak force first became distinct, 7.) photons of cosmic microwave background released
1, 2, 3, 7
During the history of the universe, what important event occurred about 0.001 seconds after the Big Bang?
Spacetime rapidly expanded during a brief period of inflation.
Most matter in the early universe was annihilated by antimatter.
Light began to travel freely through the universe.
The first massive supernovae explosions occurred.
Most matter in the early universe was annihilated by antimatter.
Which of the following important events occurred earliest in the history of the universe?
Light began to travel freely through the universe.
Spacetime rapidly expanded during a brief period of inflation.
Spacetime expansion increased the average distance between galaxies.
The first massive supernovae explosions occurred.
Spacetime rapidly expanded during a brief period of inflation
During the history of the universe, what important event occurred about 380,000 years after the Big Bang?
The first massive supernovae explosions occurred.
Most matter in the early universe was annihilated by antimatter.
Light began to travel freely through the universe.
Spacetime rapidly expanded during a brief period of inflation.
Light began to travel freely through the universe.
Essentially all the hydrogen nuclei that will ever exist in our universe was created __________.
shortly after the era of galaxies ended
at the time that the first stars and galaxies began to form
at the end of the era of nuclei, when light began to travel freely through the universe
by the time the universe was about 3 minutes old
by the time the universe was about 3 minutes old
Compared to when the cosmic microwave background was first released, the radiation of the cosmic microwave background today is __________.
brighter and has most of its photons at shorter wavelengths
fainter and has most of its photons at shorter wavelengths
fainter and has most of its photons at longer wavelengths
brighter and has most of its photons at longer wavelengths
fainter and has most of its photons at longer wavelengths
A ______ predicts that the strong, weak, and electromagnetic forces should become indistinguishable at high temperatures
- grand unified theory
- electroweak force
- inflation
- Olber's paradox
- cosmic microwave background
- annihilation
grand unified theory
The _______ is a single force that unifies the electromagnetic and weak forces
- grand unified theory
- electroweak force
- inflation
- Olber's paradox
- cosmic microwave background
- annihilation
electroweak force
_________ was a dramatic expansion of the universe thought to have occurred when the universe was only a tiny fraction of a second old
- grand unified theory
- electroweak force
- inflation
- Olber's paradox
- cosmic microwave background
- annihilation
inflation
____________ forces us to think about why the sky is dark at night
- grand unified theory
- electroweak force
- inflation
- Olber's paradox
- cosmic microwave background
- annihilation
Olber's paradox
Observations of the ____________ provide a way to our theory of the Big Bang
- grand unified theory
- electroweak force
- inflation
- Olber's paradox
- cosmic microwave background
- annihilation
cosmic microwave background
When a particle of ordinary matter meets its precise opposite particle of antimatter, the result is ___________ with complete conversion of mass to energy
- grand unified theory
- electroweak force
- inflation
- Olber's paradox
- cosmic microwave background
- annihilation
annihilation
The history of the universe can be divided into seven major phases. Taken together, these phases make up the cosmic evolutionary scheme—the continuous transformation of matter and energy that has led to the appearance of life and civilization on Earth.
Rank the phases in the history of cosmic evolution from earliest to most recent.
- stellar, galactic, biological, cultural, chemical, planetary, particulate
particulate, galactic, stellar, planetary, chemical, biological, cultural
Use these four characteristics as a working definition of life to see which generally accepted living and non-living things from the table would be considered alive based on these characteristics.They can react to their environment and can often heal themselves when damaged.
They can grow by taking in nourishment from their surroundings and processing it into energy.
They can reproduce, passing along some of their own characteristics to their offspring.
They have the capacity for genetic change and can therefore evolve from generation to generation and adapt to a changing environment.
(for things that exhibit 4 characteristics)

- dogs, trees, viruses, rocks, stars
dogs, trees
Use these four characteristics as a working definition of life to see which generally accepted living and non-living things from the table would be considered alive based on these characteristics.They can react to their environment and can often heal themselves when damaged.
They can grow by taking in nourishment from their surroundings and processing it into energy.
They can reproduce, passing along some of their own characteristics to their offspring.
They have the capacity for genetic change and can therefore evolve from generation to generation and adapt to a changing environment.
(for things that don't exhibit 4 characteristics)

- dogs, trees, viruses, rocks, stars
viruses, rocks, stars
Sort the following source properties by whether they might be considered as originating from intelligence or simply be natural phenomena. (probably cosmic)
- sequence of pulses varying over time, constant unchanging signal, identical repetitive pulses, random radio fluctuations, single strong visible light burst that fades away over months
constant unchanging signal, identical repetitive pulses, random radio fluctuations, single strong visible light burst that fades away over months
Sort the following source properties by whether they might be considered as originating from intelligence or simply be natural phenomena. (possibly extraterrestrial)
- sequence of pulses varying over time, constant unchanging signal, identical repetitive pulses, random radio fluctuations, single strong visible light burst that fades away over months
sequence of pulses varying over time
As the mass of the central star increases, the distance to the habitable zone __________ and the size (width) of the habitable zone __________.
Select from the choices in the format first blank / second blank.
decreases / increases
increases / increases
increases / decreases
decreases / decreases
increases / increases
Suppose that our Sun was cool enough to include Mercury in its habitable zone. Which of the following would be true in that case?
Only Mercury would be in the Sun's habitable zone.
Mercury and Venus would be in the Sun's habitable zone, but Earth and Mars would not.
Mercury, Venus, and Earth would be in the Sun's habitable zone, but Mars would not.
All the terrestrial planets would be in the Sun's habitable zone.
Only Mercury would be in the Sun's habitable zone.
Scientists think it is very unlikely that complex and large forms of life could evolve on planets that orbit stars that are much more massive than the Sun. Why?
The expected lifetime of a massive star is too short to allow for the evolution of complex life
The habitable zone of a massive star covers too wide a range of distances from the star to allow for the evolution of complex life
The habitable zone of a massive star is too far from the star to allow for the evolution of complex life
The expected lifetime of a massive star is too short to allow for the evolution of complex life
What is the average rate of star formation in our Galaxy?
1 star every year
Star formation has ceased to occur in our Galaxy.
1 star every 10 years
10 stars every year
50 stars every year
10 stars every year
What is the "stellar habitable zone"?
The range in temperatures of a star around which a terrestrial planet with Earth's mass and density is expected to form.
The range of distances from a star in which a terrestrial planet with Earth's mass and density is expected to form.
The range in temperatures of a star around which an Earth-like planet at a distance of 1 AU could sustain water.
The range of distances from a star in which an Earth-like planet could sustain liquid water.
The range of distances from a star in which an Earth-like planet could sustain liquid water.
Do astronomers expect to find planets around binary stars that are stable enough for life to develop? Why?
No. Planets won't form at all in binary systems.
No. Planets may form in binary systems, but their orbits won't be stable.
Yes. It is possible for a planet stable enough for life to develop to form a stable orbit in a binary system.
No. Planets may form stable orbits in binary systems, but the conditions on them won't be conducive to developing life.
No. Planets may form stable orbits in binary systems, but the conditions on them won't be conducive to developing life.
Why do astronomers consider very long-wavelength, low-frequency radio waves not to be a good range to search for an extraterrestrial signal?
Radio waves at such long wavelengths require too much energy to be generated.
Long-wavelength radio waves are blocked by dust in the galactic plane.
There are too many natural galactic sources that cause noise at these wavelengths.
Molecules in Earth's atmosphere naturally emit radiation at these wavelengths, causing noise.
There are too many natural galactic sources that cause noise at these wavelengths.
Robot probes sent to the other planets of the solar system have demonstrated that life as we know it exists on which of the following?
On the planet Mars
On the moon Europa
Only on Earth
On the moon Titan
Possibly on Jupiter
only on earth
The Viking lander experiments that chemically searched for life on Mars could not have detected which of the following?
Seeds
Living organisms
Fossils
Spores
Fossils
The most likely region of the radio spectrum for communication with other civilizations is in the "water hole." What part of the spectrum is this?
Between the radio emissions of hydrogen and oxygen
Around the radio emission of water molecules
Around the radio emission of oxygen molecules
Between the radio emissions of hydrogen and OH
between the radio emissions of hydrogen and OH
In what sense are viruses on the border between material that we consider living and that we consider nonliving?
Viruses do not take in nourishment from their surroundings.
Viruses have no capacity for genetic change.
Viruses cannot reproduce on their own but must make use of the genetic machinery of the cells they invade to multiply.
Viruses contain no DNA or RNA, only simple molecules that govern their functions.
Viruses cannot react to their environment and can only make simple copies of themselves on their own.
Viruses cannot reproduce on their own but must make use of the genetic machinery of the cells they invade to multiply
According to available physical and biological evidence, when did multicellular organisms first appear on Earth?
About 200 million years ago
A few thousand years ago
About 1 billion years ago
About 3 billion years ago
About 1 million years ago
About 1 billion years ago
What is chemical evolution?
The evolution of biologically important chemicals from nonbiological chemicals
The process by which certain chemicals move through the environment, changing as they do so
The evolution of the minerals of the land and material in the sea and air
The process by which exposure to chemicals mutates or evolves life-forms on Earth
The evolution of biologically important chemicals from nonbiological chemicals
What were the first biologically important molecules produced in the Miller-Urey experiments?
Amino acids
DNA
Genetic bases
Proteins
Amino acids
What environmental factor works against Mars having any life on its surface?
Complete lack of water
Its rate of rotation
Lack of a magnetic field
Carbon dioxide atmosphere
lack of magnetic field
What is the most important piece of evidence known about Mars that suggests it once had an environment that could be supportive of life?
Ice caps
Rotation rate
Dry river and lake beds
Volcanoes
dry river and lake beds
What question does the Drake equation attempt to answer?
What is the number of technological civilizations in the Galaxy?
How many planets are inhabited by life?
What number of stars have planetary systems?
What defines the habitable zone around any star?
What is the number of technological civilizations in the Galaxy?
What is the meaning of the term extremophiles?
Planets that orbit either very close to or very far from their parent star
Life-forms that have adapted to live in extreme environments
Scientists who postulate unorthodox methods for finding extraterrestrial life
Scientists who believe there is an infinitesimal, yet nonzero, chance of finding extraterrestrial life
life-forms that have adapted to live in extreme environments
Mixing water, methanol, ammonia, and carbon monoxide. The purpose of this experiment was to determine whether...
amino acids could form in the harsh vacuum of outer space
Simplest life forms appeared on Earth when it was how old?
one billion years
How long between the evolution of single versus multicellular organisms?
2.5 billion years
the formed meteorite with carbonate rocks and possible microfossils came from...
Mars
For which of these forms of life is it hardest to apply present criteria for life, based on its behaviour when isolated?
virus
why is the hypothesis that life on Earth came from outer space considered plausible?
many meteorites contain complex organic molecules
Addition to Mars, which jovian moon shows promise of life, with a surface not that different from the Arctic ocean?
Europa
Life that creates energy through chemical reactions (chemosynthesis instead of photosynthesis) and live in environments thought to be too hot, alkaline, etc. are called...
extremophiles
Assuming conditions are ripe for life and intelligence around the galaxy, what factor limits the number of galactic civilizations?
average survival time of the civilizations
According to our definition, we have been a technological civilization for about...
100 years
Why do we feel type O and B stars are poor candidates for extraterrestrial life?
their lifetime is too short
What is meant by the "habitable zone"?
region around each star where terrestrial planets could have water on their surfaces
Considering luminosity and longevity, which of these would be the most likely candidate for seeking extraterrestrial intelligence?
61 Cygni (a K type main sequence star)
the first probe carrying mankind's message to alien civilizations was...
Pioneer 10