Magnetic fields in our galaxy trap
A) cosmic rays.
B) radio waves.
C) spectral lines.
.The proportionality between the recession speeds of the galaxies and their distances from the earth is known as
A) Hess’s Law.
B) Herschel’s Law.
C) Hubble’s Law.
D) Hersey’s Law.
. A star must have a certain minimum mass in order that gravity squeeze its matter sufficiently to
A) hold it together as a single body.
B) produce a temperature high enough for it to glow.
C) produce a temperature high enough for nuclear reactions to start.
D) turn its interior into liquid hydrogen.
. The sun is
A) a Population I star.
B) a Population II star.
C) different from Population I and II stars.
D) a member of a globular cluster.
. The most distant galaxies are receding at speeds that are
A) much less than the speed of light.
B) not far from the speed of light.
C) equal to the speed of light.
D) greater than the speed of light.
. The interior of the sun consists of
A) liquid hydrogen.
C) neutral atoms.
. Information about the origin of the universe does not come from the
A) fact that spiral galaxies rotate.
B) red shifts in galactic spectra.
C) relative abundances of hydrogen and helium.
D) cosmic background radiation.
. The number of stars in our galaxy is approximately
B) 10 million.
C) 1 billion.
D) 100 billion.
. White dwarf stars are not
A) comparable in size with the earth.
B) comparable in mass with the sun.
C) extremely hot.
D) extremely bright.
. Compared with the Population I stars in the disk of our galaxy, the Population II stars in the globular clusters around it are
B) about the same age.
D) Any of these choices are correct.
. The source of the sun’s energy is
B) nuclear fission.
C) nuclear fusion.
. In the light of current evidence, a reasonable figure for the age of the universe is
A) 13.7 million years.
B) 13.7 billion years.
C) 100 billion years.
D) 15 trillion years.
. Molecules in space can be identified from their emissions of
A) light waves.
B) radio waves.
C) cosmic waves.
. In the universe today there
A) seems to be no antimatter.
B) is some antimatter but less than the amount of matter.
C) are equal amounts of antimatter and matter.
D) is more antimatter than matter.
. Binary stars are valuable to astronomers because they permit the determination of stellar
. Stars seem to twinkle because of
A) variations in their brightnesses.
B) variations in their colors.
C) turbulent movements in their atmospheres.
D) turbulent movements in the earth’s atmosphere.
. Some, and perhaps all, spiral galaxies have at their centers
C) black holes.
D) globular star clusters.
. At the end of its period in the main sequence, a very heavy star
A) breaks up into several smaller stars.
B) cools down into a white dwarf.
C) expands into a red giant.
D) explodes into a supernova.
. In the HR diagram, most stars are
A) members of the main sequence.
B) red giants.
C) white dwarfs.
D) scattered at random.
. A supernova explosion may leave behind which one or more of the following?
A) a black hole
B) a neutron star
C) a pulsar
D) a red giant
E) Both A, B and C