AST 180 Final
True or False: Astrobiology is pseudoscience not recognized by large science funding agencies like NASA
False
Which of the following is closest to the main-sequence lifetime of a star that is half as massive as the Sun? a. 200 billion years b. 500 million years c. 15 million years d. 5 billion years e. 20 billion years
a. 200 billion years
What is located in the nucleus of the Galaxy? a. A Black Hole b. An HII region c. A Spiral Arm d. A Globular Cluster e. The Solar System
a. A Black Hole
Which of the following have been used as possible explanations for the accelerating universe? a. Cosmological constant and quintessence b. Speed of light and gravitational constant c. Inflation force d. matter-antimatter annihilation e. Hubble constant and inflation parameter
a. Cosmological constant and quintessence
What is the source of energy that enables a main-sequence star to shine? a. Fusion of hydrogen in its core b. Fusion of hydrogen in a shell that surrounds the core c. Fusion of helium in its core d. Friction between its atoms e. Burning of gases on its surface
a. Fusion of hydrogen in its core
Which of the following refers correctly to a region on the HR diagram where Helium-burning stars pulsate and exhibit variable luminosity? a. Instability Strip b. Luminosity Class IIa c. Cepheid Sequence d. Asymptotic Giant Branch e. RR Lyrae Track
a. Instability Strip
How does the hydrogen atom emit a photon with a wavelength of 21 cm (radio) that allows us to probe the galaxy's structure? a. Its proton and electron change from a configuration in which their spins are aligned to one in which they are anti-aligned b. Its proton and electron change from a configuration in which their spins are anti-aligned to one in which they are aligned. c. Its single electron goes from a high-energy orbital to a low-energy one. d. The Hydrogen atom changes its rotation rate. e. Its single electron goes from a low-energy orbital to a high-energy one
a. Its proton and electron change from a configuration in which their spins are aligned to one in which they are anti-aligned.
What do astronomers conclude from observations of the orbital speeds of stars at the edge of the galaxy? a. much of the galaxy consists of "dark matter" that we do not detect. b. proof of Einstein's Theory of Relativity c. Many stars are falling toward the center of the Galaxy d. Satellite galaxies are the dominating gravitational influence e. the Galaxy obeys Kepler's Laws
a. Much of the galaxy consists of "dark matter" that we do not detect.
What can you learn from the "turnoff" point on the HR diagram for a globular cluster? a. The cluster's age b. Th cluster's metallicity c. The cluster's temperature d. The cluster's distance e. The cluster's mass
a. The cluster's age
Consider a star behind a cloud of interstellar gas and dust as seen from our perspective. Which of the following would you see? a. The star appears redder then it would if the cloud were not present b. The star appears to be moving toward us c. The star would always appear green d. The star would be invisible at all wavelengths. e. The star appears brighter than it would if the cloud were not present
a. The star appears redder than it would if the cloud were not present
Where in the galaxy is in the solar system located? a. between two spiral arms b. in the halo c. in the nucleus d. in the bulge e. in a spiral arm
a. between two spiral arms
Most of the apparently bright stars in the sky are bright because they are close to our Sun (within 5 parsecs). a. Correct b. Wrong: most are intrinsically bright and lie far from the Sun c. Wrong: "Close" means closer than 1 parsec d. Wrong: both B and C changes are needed
a. correct
What question was the topic of the "Great Debate" between Harlow Shaplet and Herber Curtis in 1920? a. Does the Milky Way contain all the stars in the universe? b. Is the sun at the center of the milky way? c. did all stars form shortly after the big bang? d. are planets common? e. Is the milky way composed of stars or gas?
a. does the milky way contain all the stars in the universe?
What is the weakest force in nature? a. gravity b. weak force c. strong force d. electromagnetic force
a. gravity
What evidence shows that the universe is expanding? a. The most distant galaxies show red-shifted emission b. nearby galaxies appear stationary c. the most distant galaxies show blue-shifted emission d. the most distant galaxies are stretched out
a. the most distant galaxies show red-shifted emission
Which of the following places would be the most likely to harbor planets and life? a. The regions of the Milky Way farthest from its center b. A zone that is mid-way between the center and the outermost regions of the Milky Way c. Intergalactic space d. Elliptical Galaxies e. The Galactic Center in the Milky Way
b. A zone that is mid-way between the center and the outermost regions of the Milky Way
Which part of the Milky Way is spherically distributed and extends beyond the stars at the outer edge of the galaxy? a. Galactic Nucleus b. Halo c. Spiral Arms d. Nuclear Bulge e. Thick Disk
b. Halo
When our Sun first reaches the Red Giant Phase, its size will be most like which of the following? a. Its radius will be as large as the semi-major axis of Mars' orbit b. Its radius will be as large as half the semi-major axis of Earth's orbit c. Its radius will be as large as the semi-major axis of Mercury's orbit d. Its radius will be as large as half the semi-major axis of Venus's orbit e. Its radius will be as large as the semi-major axis of Jupiter's orbit
b. Its radius will be as large as half the semi-major axis of Earth's orbit
The "Mass-Luminosity relationship" refers to which of the following principles? a. Bright giant stars lose mass in a stellar wind. b. Main-sequence stars have luminosities that increase with increasing mass c. Main-sequence stars have luminosities that decrease with increasing mass d. Main-sequence stars lose their mass in order to maintain their luminosity
b. Main-sequence stars have luminosities that increase with increasing mass
Which of the following is a term for a group of high mass stars? a. T Tauri association b. OB association c. HII region d. Globular Cluster e. Protostellar cluster
b. OB association
Which of the following sequences of spectral types give star classes in order of decreasing temperature, from hottest to coolest? a. MKGFABO b. OBAFGKM c. KOMFBAG d. OABFGKM e. OBAGFKM
b. OBAFGKM
Why does SETI operate primarily at radio frequencies? a. So we can detect extraterrestrial radio stations b. Radio waves can travel great distances without being altered by the interstellar medium c. so we can intercept intergalactic radio communications d. Radio waves travel faster than light waves
b. Radio waves can travel great distances without being altered by the interstellar medium
What information can be obtained from observations of an eclipsing binary? a. the spectral types of both stars b. The orientation of the binary star orbital plane. c. The masses of both stars d. The age of the brightest star e. The metallicity of the stars
b. The orientation of the binary star orbital plane.
Why are planets around the most massive stars not a good place to look for life? a. Planets in their habitable zones would be tidally locked into synchrous rotation b. Their main sequence lifetimes are too short c. Their main sequence lifetimes are too long d. They don't radiate enough energy e. They radiate too much energy
b. Their main sequences lifetimes are too short
Stellar parallax can be used to do which of the following? a. Determine the radial velocity of a nearby star b. Calculate the distance to a nearby star. c. measure the brightness of a nearby star d. measure the proper motion of a nearby star
b. calculate the distance to a nearby star
Which element serves as the foundations or "backbone of life"? a. oxygen b. carbon c. silicon d. hydrogen nitrogen
b. carbon
Which of the following statements best fits the term "organic molecules"? a. molecules made by life b. Carbon-based compounds c. any large complex molecules d. molecules made of oxygen, hydrogen, and nitrogen.
b. carbon-based compounds
Compared to a star of a spectral type K, a star of spectral type A is generally: a. hotter, more luminous, and less massive b. hotter, more luminous, and more massive c. cooler, dimmer, and less massive
b. hotter, more luminous, and more massive
Which of the following was not a possible outcome of Einstein's original equations of general relativity? a. the universe might be contracting b. the universe is static c. The universe might be expanding
b. the universe is static.
A star with which of the following apparent magnitudes appears brightest from Earth? a. 6.8 b. -0.44 c. -1.5 d. 0.41 e. 3.2
c. -1.5
What is the lowest mass that a star can have on the main sequence? a. There is no lower limit b. 0.4 solar masses c. 0.08 solar masses d. 0.003 solar masses e. 2.0 solar masses
c. 0.08 solar masses
The cosmic microwave background is currently associated with a temperature that is closest to which of the following? a. 379,000 degrees Kelvin b. 273 degrees Kelvin c. 3 degrees Kelvin d. 108,000 degrees Kelvin e. 5,777 degrees Kelvin
c. 3 degrees Kelvin
Where are the youngest stars located on the HR diagram? a. Along a line that intersects the main sequence b. Below and to the left of the main sequence c. Above and to the right of the main sequence d. Above and to the left of the main sequence e. Along the main sequence
c. Above and to the right of the main sequence
Which type of meteorite is most likely to have the chemical signature of organics from the early solar system? a. Stony b Iron c. Carbonaceous Chondrite d. Stony Iron
c. Carbonaceous Chondrite
Which of the following refers to a region of interstellar gas and dust that glows due to energy it receives from nearby stars? a. Diffuse Interstellar cloud b. Dark Nebula c. Emission Nebula d. Giant Molecular Cloud e. Reflection Nebula
c. Emission Nebula
For a star with a mass like our Sun's, what happens when it begins to fuse Helium in the core? a. It becomes a neutron star b. It blows up in a supernovae c. It contracts and its surface gets hotter d. It enters the white dwarf stage e. It expands and its surface cools.
c. It contracts and its surface gets hotter
Which best describes the Miller-Urey experiment? a. Observations of lipids in water that fragment to form coacervates b. Efforts to polymerize proteins with repeated cycles of drying and wetting c.Production of life's building blocks with a laboratory simulation of the atmospheric conditions of early Earth d. Testing of different sites as possible environments for the origin of life e. Simulations of the atmosphere of Titan
c. Production of life's building blocks with a laboratory simulation of the atmospheric conditions of early Earth
Which of the following quantities is estimated by the Drake Equation? a. The number of planets with life on them. The number of intelligent species on earth b. The star formation rate in the galaxy c. The number of galactic civilizations that are sending a radio signal d. The number of planets on which life gets started
c. The number of galactic civilizations that are sending a radio signal.
Which best describes the terms "Pair Production" and "Pair Annihilation"? a.The formation of binary galaxies at a collapsing center of dark matter and the destruction of interacting galaxies that collide b. The formation of binary stars at a collapsing molecular cloud core and the destruction of interacting stars that collide c. The production of particle-antiparticle pairs from radiative energy and their destruction when they encounter one another d. The formation of a deuterium nucleus with two baryons and its destruction during the high temperatures of nuclear fusion burning
c. The production of particle-antiparticle pairs from radiative energy and their destruction when they encounter one another.
In 1917, Harlow Shapley determined distances to Globular clusters and inferred which of the following? a. The Sun is at the center of the galaxy b. The Milky Way is configured with several spiral arms c. The sun is not at the center of the galaxy d. The Milky Way is just one of many galaxies e. The sun lies between two spiral arms
c. The sun is not at the center of the galaxy.
Which is not one of the places in the solar system where scientists plan to look for extraterrestrial primitive life, according to the text? a. Mars b. Europa c. Venus d. Ganymede
c. Venus
The brightness of a star would have if it were a 10 pc from Earth is called which of the following? a. spectral type b. center of mass c. absolute magnitude d. apparent magnitude e. luminosity
c. absolute magnitude
What is the future of our universe if it is "closed"? a. It will reach zero degrees b. It will expand for awhile and then become still c. It will expand for awhile and then contract back on itself d. It will expand forever
c. it will expand for awhile and then contract back on itself
Which of the following was an outcome of the Miller-Urey experiment? a. The formation of a living protocell b. The polymerization of nucleotides c. the formation of amino acids d. the formation of coacervates
c. the formation of amino acids
When we look at the surface of the cosmic microwave background, we are seeing structure in the universe as it appeared at which of the following times after the big bang? a. 10-21 seconds after the Big Bang b. A "Planck Time" after the Big Bang c. 4.5 Billion years after the Big Bang d. 379,000 years after the Big Bang e. Now
d. 379,000 years after the Big Bang
What is revealed by the orbits of stars near the galactic center? a. A pulsar b. Synchrotron Emission c. Magnetic Fields d. A super-massive black hole e. A globular cluster
d. A super-massive black hole
Which of the following refers to a star that is more massive than the Sun, pulsates with a period that is proportional to its luminosity, and functions as a useful distance indicator? a. T Tauri Star b. OB association c. RR Lyrae Star d. Cepheid Variable e. Eclipsing Binary
d. Cepheid Variable
Which of the following properties can be used by itself to estimate a star's surface temperature? a. Magnitude b. Apparent brightness c. Radial Velocity d. Color e. Distance
d. Color
Which of the following refers to the time when universe cooled enough for electrons to become bound to nuclei in atoms? a. Period of Radiation Domination b. Eon of supersymmetry c. Epoch of inflation d. Era of recombination e. Planck Time
d. Era of recombination
Which stellar spectral type is most likely to have a planet upon which advanced life exists? a. O b. B c. A d. G e. M
d. G
Which of the following refers to the search for brown dwarfs, black holes, or similarly faint but massive objects in the galactic Halo by means of technique of gravitational microlensing? a. WIMPS b. NACHOS c. BLIMPS d. MACHOS e. HII regions
d. MACHOS
Which observations reveal the the expansion of the universe is accelerating? a. Gravity waves from the Planck Time b. Cepheid variables as standard candles in the Hubble Law c. High Resolution imaging of the Cosmic microwave background d. Supernovae as standard candles for the Hubble Law
d. Supernovae as standard candles for the Hubble Law
Which of the following is true for a binary system of two stars with mass, MA and MB, where MA is greater than MB? a. The center of mass lies midway between Earth and the binary system. b. The center of mass lies midway between the stars w/ masses MA and MB c. The center of mass lies between the stars w/ masses MA and MB, but the star with mass MB is closer to the center of mass than the star with mass MA d. The center of mass lies between the stars with masses MA and MB, but the star with mass MA is closer to the center of mass than the star with mass MB e. The center of mass lies midway between both stars.
d. The center of mass lies between the stars w/ masses MA and MB, but the star with mass MA is closer to the center of mass than the star with mass MB
What evidence has been observed that indicates the universe was once in an unimaginably hot and dense state? a. Gamma Ray Bursters b. Gravity Waves c. Synchrotron radiation d. The cosmic microwave background radiation e. Pulsars
d. The cosmic microwave background radiation
Which of the following does not correspond to one of the terms on the right hand side of the Drake Equation? a. Rate at which Sunlike stars form. b. Fraction of habitable planets on which life arises. c. Average lifetime of technologically advanced civilizations d. The number of planets with liquid water on the surface
d. The number of planets with liquid water on the surface
Which of the following is the best description of the Habitable Zone in a planetary system? a. Any place where life can live b. All the regions on a planet where life resides c. A region in the Galacy where metallicity is just right for planet formation d. The range of distances from a star where liquid water can exist on the surface of a planet. e. The parts of the universe where stars have had time to evolve life
d. The range of distances from a star where liquid water can exist on the surface of a planet
Which of the following is not a feature of the "Water Hole" as it relates to SETI search strategies? a. A spectral region close to a spectral line of atomic hydrogen b. A range of frequencies higher than those of galactic synchrotron emission c. A range of frequencies lower than those of prominent atmospheric molecular emissions d. A spectral region where the cosmic microwave background emission is at a minimum e. A spectral region close to spectral lines of the hydroxide molecule
d. a spectral region where the cosmic microwave background emission is at a minimum.
Measurements of a binary star system are required to determine what property of stars? a. luminosity b. apparent magnitude c. distance d. mass e. temperature
d. mass
The sum of the masses of two binary stars is equal to which of the following terms? a. The period squared b. the square of the semimajor axis divided by the cube root of the period c. the period divided by the semimajor axis d. The cube of the semimajor axis divided by the square of the period e. The square root of the period divided by the cube of the semimajor axis
d. the cube of the semimajor axis divided by the square of the period.
How long does it take the Sun to complete one trip around the galaxy? a. 26,000 Light Years b. 828,000 years c. One Year d. 343 Years e. 230 Million Years
e. 230 Million years
Which best describes a "double-line" spectroscopic binary? a. A binary where the spectrum of only one binary can be seen, but the Doppler shift due to its orbital motion causes the spectral lines to be seen in two different places b. A binary where two or more spectral lines are observed from at least one source c. A binary where the spectrum of two different stars can be seen simultaneously without any Doppler shift d. A binary where the spectral lines are split into two by magnetic effects. e.A binary where the Doppler shift due to the orbital motion of both components can be traced in spectral lines detected from both stars
e. A binary where the Doppler shift due to the orbital motion of both components can be traced in spectral lines detected from both stars.
Which of the following objects are useful as indicators of the distances to galaxies? a. Radial Velocity Stars b. Cepheid and Cataclysmic Variables c. Pulsars and Cepheid Variables d. Black Holes and Neutron Stars e. Cepheid Variables and Supernovae
e. Cepheid Variables and Supernovae
Which term is used by cosmologists to refer to the idea that the universe appears the same in all directions? a. Isogeneity b. Spherical symmetry c. Omni-directionality d. Homogeneity e. Isotropy
e. Isotropy
The apparent luminosity of a light source changes with distances in which of the following ways? a. It is proportional to the inverse of the distances b. It is proportional to the inverse of the square root of the distance. c. It is proportional to the square of the distance d. It is proportional to the distance e. It is proportional to the inverse of the square of the distance
e. It is proportional to the inverse of the square of the distance.
What is the term for a young star that is no longer accreting mass but has not yet begun to burn hydrogen in its core a. young cluster b. young stellar object c. Class I object d. Protostar e. Pre-main-sequence star
e. Pre-main-sequence star.
Which term refers to radio emission produced by high-speed electrons that spiral around magnetic fields at the galactic center? a. Cosmic Microwave Background b. Microwaves c. HI emission d. Masers e. Synchrotron Radiation
e. Synchrotron Radiation
Which of the following provides an estimate of the age of the universe? a. The cosmological constant b. The inverse cosmological constant c. The square of the inverse speed of light d. The Hubble constant squared e. The inverse Hubble Constant
e. The inverse Hubble constant
Which stage of stellar evolution take the longest time? a. The time during which it burns hydrogen in a shell b. the time during which it burns helium in the core c. The time during which it burns helium in a shell d. The time interval from when the star begins to form to when it begins to burn hydrogen. e. The time during which it burns hydrogen in the core and is in hydro static equilibrium
e. The time during which it burns hydrogen in the core and is in hydro static equilibrium
How did Edwin Hubble determine the distance to other galaxies? a. The Doppler Effect b. Spectroscopic Parallax c. Using the Main Sequence Turnoff d. Trigonometric Parallax e. Using Cepheid Variable stars
e. Using Cepheid Variable stars
Which of the following lists only wavelengths that are useful for studying the center of the galaxy? a. Gamma-Ray, UV, and Visible b. X Radio,X-ray, gamma-ray an infrared c. UV, visible, infrared d. Visible, UV and infrared e. Visible, infrared and Radio
e. Visible, infrared and Radio
Which of the fundamental four forces in nature is believe to have formed first? a. weak force b. electromagnetic force c. strong force d. all formed at the same time e. gravity
e. gravity
Which of the following is/are (a) direct consequence(s) of the hypothesized inflationary epoch in the early universe? a. Gravitational Lensing b. Quasars c. Cosmic microwave background d. relative abundances of Hydrogen and Helium e. homogeneity and isotropy
e. homogeneity and isotropy
Which of the following is not known to be a component of the interstellar medium? a. polycyclic aromatic hydrocarbons b. dust grains c. atoms d. molecules e none of the above
e. none of the above
Which statement about the milk way galaxy is correct? a. Most stars in our galaxy are in nuclear bulge b. Our galaxy contains all stars in the universe c. none of the stars in our galaxy move d. all stars in our galaxy take the same time to complete one orbit e. our galaxy is but one of many galaxies
e. our galaxy is but one of many galaxies
The Hertzsprung-Russell diagram plots which of the following properties of stars? a. temperature & mass b. brightness & mass c. color & size d. radius &mass e. spectral type & luminosity
e. spectral type & luminosity