100. One cosmological view is that the universe is "closed" and will stop expanding. This
view is based on the proposition that:
a. the density of the universe is equal to the critical density.
b. the density of the universe is less than the critical density.
c. the density of the universe is greater than the critical density.
d. the density of the universe has no effect on its fate.
100. Which of these is NOT a basic assumption of cosmology?
a. Expansion of the universe.
b. Universality of physical laws.
c. Homogeneity of the universe.
d. Isotropy of the universe.
100. Einstein's famous E=mc2 tells us that:
a. tremendous temperatures and energies are needed to make just a little particle.
b. conversion of lot of matter in stellar fusion can produce little energy.
c. as the Big Bang cooled, the less massive particles froze out first.
d. protons were formed after the electrons and positrons.
100. The definition of cosmology is:
a. the study of Isotropy and Homogeneity.
b. the study of cosmetics and their application.
c. the study of the evolution of galaxies.
d. the study of the formation and evolution of the entire universe.
100. The rotation curves of distant spiral galaxies let astronomers measure their:
a. age.
b. red shift.
c. mass distribution.
d. distance.
100. Given two identical galaxies, if A appears a third as large as B, you can infer that:
a. galaxy A is 3 times closer than galaxy B.
b. galaxy A is 3 times farther away than galaxy B.
c. galaxy A is 9 times closer than galaxy B.
d. galaxy A is 9 times farther away than galaxy B.
100. What observation convinced Hubble that M 31, the Andromeda Galaxy, was indeed a
separate galaxy?
a. Its trigonometric parallax.
b. Its large angular diameter.
c. Its spiral structure
d. Cepheid variables within its spiral arms.
100. In order to infer the distances to other galaxies, we ASSUME:
a. all galaxies are the same.
b. the universe is expanding.
c. the stars in all galaxies are the same.
d. the same types of objects are the same in all galaxies.
100. The red shift measured in the spectrum of a galaxy tells you:
a. how much mass it has, in total.
b. the temperatures of the stars it contains.
c. it is moving away from us and its speed of recession.
d. it is moving toward us and its speed of approach.
100. To numerically determine the Hubble constant, you have to measure:
a. luminosity and distance of galaxies.
b. distance and recessional velocity of planets.
c. distance and luminosity of active galaxies.
d. recessional velocity and distance of galaxies.
100. Which of these objects lies within the boundary of the Milky Way?
a. M-31 in Andromeda.
b. The Large Magellanic Cloud.
c. M-42, the Orion Nebula.
d. The Small Magellanic Cloud.
100. According to Einstein's general theory of relativity, what will happen to an object
thrown into a black hole after it crosses the Schwarzschild radius?
a. It is crushed into a singularity and trapped forever.
b. It is thrown back at the speed of light.
c. It will eventually be recycled as antimatter.
d. It will be ejected as material in the bipolar jets.
100. Which of the following are thought to be made ONLY in a supernova explosion?
a. Iron.
b. Oxygen.
c. Carbon.
d. Uranium.
100. Why is it that a supernova from a very massive star can produce a black hole instead of a neutron star?
a. Because of the intense magnetic fields.
b. Because the gravitational pressure overcomes the neutron degeneracy pressure.
c. Because the neutron escape velocity is exceeded.
d. Because the gravitational pressure crushes the electron orbitals.
100. Consider the end of a star's life. If it is like our sun, it will finish burning off hydrogen, blow off its envelope, and leave a carbon core that is hot but not nearly as luminous as the giant stage previously. These objects are called:
a. supernovae.
b. eclipsing binary stars.
c. white dwarfs.
d. brown dwarfs.
100. In a binary star system, the region around each star where gravitational force dominates is called the:
a. Roche lobe.
b. light radius.
c. corotational radius.
d. synchrotron region.
100. Interstellar dust can be readily detected by its:
a. emission lines at 21 cm.
b. absorption lines at millimeter wavelengths.
c. blocking out of starlight.
d. absorption at radio wavelengths.
100. Current ideas picture interstellar dust grains as:
a. small (micrometers), made of ices only.
b. small (micrometers), made of ices and rocky materials.
c. small (micrometers), made of ices, rocks, and metals.
d. large (meters), made of ices, rocks, and metals.
100. The observations of bipolar outflows of gas from regions of star formation in molecular clouds indicate:
a. newly born stars move in two directions.
b. a ring or torus of material around the young stars.
c. hot dust causes the gas to move rapidly.
d. every star forms with a planetary system.
100. The two most abundant solar elements, in terms of its mass, are:
a. carbon and oxygen
b. helium and carbon.
c. hydrogen and oxygen.
d. hydrogen and helium.
100. What is inferred to be the source of the sun's energy now?
a. Fusion reactions in the core.
b. Gravitational energy released by collapse.
c. Fission reactions in the core.
d. Oxidation of materials such as carbon.
100. 54. As the sun ages, the chemical composition of its core changes so that it contains a lower
percentage of ____________ and a greater percentage of ______________.
a. helium, hydrogen
b. uranium, lead
c. hydrogen, helium
d. oxygen, carbon
100. Increased activity of the Sun as evidenced by an increased occurrence of sunspots and prominences is associated with:
a. solar flares.
b. a reduction in the period of solar activity.
c. no neutrino emission from the Sun.
d. the Vernal equinox.
100. One way to measure the distance to stars (near to us) is to use trigonometric parallax. To improve this technique, you can:
a. make your measurements from Mercury.
b. reflect radar off of the surface of the star and compare the distance.
c. confine your observations to one-fourth of a year
d. make your measurements from an orbit larger than the earth's.
100. To determine the mass of our Sun, we:
a. use the trigonometric parallax.
b. extrapolate from the density of the chromosphere.
c.
use Kepler's
third law and
d. use the observed temperature and spectral analysis.
100. Which of these could best be seen during a total solar eclipse?
a. Sunspots.
b. Prominences.
c. Granulation.
d. The photosphere.
100. In the condensation sequence, the terrestrial planets end up with very little hydrogen and helium (compared to the Jovian planets) because the:
a. original nebula contain little hydrogen and helium.
b. sun drew in hydrogen and helium from the inner nebula.
c. temperatures were too high for these to condense.
d. temperatures were too low for these to condense.
100. The ionic tail of a comet points:
a. along the Earth-Sun direction.
b. along the direction of motion.
c. along the line connecting the earth and the comet.
d. along a line joining the comet and the Sun.
100. Meteoroids are determined to be about 4.6 billion years old. This means that:
a. they formed at the same time as the Earth.
b. they formed near Jupiter.
c. they formed in the Oort cloud.
d. they are of extra-galactic origin.
100. The most widely accepted version of the extinction of the dinosaurs presently is that:
a.
a large asteroid struck the
b.
great volcanic eruptions in
c. a nearby supernova showered the Earth with intense cosmic rays.
d. the mammals ate up all the dinosaur eggs.
100. For a star like our sun, once fusion reactions in the main sequence phase stop, the star will next become a:
a. white dwarf.
b. black dwarf.
c. red giant.
d. blue supergiant.
100. Which of these is NOT a major difference between the evolution of a one and a five solar mass star?
a. The more massive star has a shorter lifetime.
b. The more massive star fuses hydrogen by the CNO cycle on the main sequence.
c. The less massive star produces helium by fusing four hydrogens atoms in its core.
d. The more massive star may end its life in a supernova explosion.
100. In an evolving cluster, which stars become red giants first?
a. Stars with masses like the sun's.
b. Stars with sizes smaller than the sun's.
c. The most massive stars (upper main sequence).
d. The stars with the most heavy elements.
100. In a collapsing region of gas and dust does not produce enough energy in the core to ignite nuclear fusion, it will become a:
a. WIMP (weakly interacting magnetic protostar).
b. proton star.
c. white dwarf.
d. brown dwarf.
100. Our Sun is now in an evolutionary stage that lies on the __ of the H-R diagram.
a. Pre-main sequence
b. main sequence
c. type I sequence
d. post-main sequence
100. The balance between ______ forces and ______ forces determines the size of a star.
a. radiation/gravitation
b. gravitation/magnetic
c. gravitation/electromagnetic
d. gravitation/convective
100. What causes the temperature of a star to rise if the fusion reactions have stopped?
a. Gravitational contraction.
b. Laser irradiation.
c. Helium burning.
d. Hydroelectric power.
100. In order to find out the spiral arm structure of the Galaxy, a radio astronomer needs to:
a. know the galactic rotation curve and measure the Doppler shift of 21-cm lines.
b. infer the velocities of clouds along the line of sight.
c. know the sizes of the H II regions he is observing.
d. be able to match H I regions to bright associations of young blue stars.
100. Which of the following would you NOT expect to find in a spiral arm of the Galaxy?
a. H I regions.
b. H II regions.
c. Molecular clouds.
d. Globular clusters.
100. In the halo of the Galaxy in the future, we expect:
a. more supermassive stars to form.
b. globular clusters to orbit and hot gas to flow out from the disk.
c. brown dwarf stars to be the main type of star forming.
d. hot gas to flow inward toward the nucleus.
100. Where in the Galaxy is most of the Milky Way's gas and dust?
a. Core.
b. Nuclear bulge.
c. Spiral arms.
d. Halo.