ASTR 121|92 exam 2 Final Exam Questions Correctly Answered|2024
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Course
ASTR 121
Institution
ASTR 121
A charming friend of yours who has been reading a little bit about astronomy accompanies you to the campus observatory and asks to see the kind of star that our Sun will ultimately become, long, long after it has turned into a white dwarf. Why is the astronomer on duty going to have a bit of a prob...
A charming friend of yours who has been reading a little bit about astronomy accompanies you to the
campus observatory and asks to see the kind of star that our Sun will ultimately become, long, long after
it has turned into a white dwarf. Why is the astronomer on duty going to have a bit of a problem
satisfying her request? - ✔ ✔ after a white dwarf cools off it becomes too cold and dark to emit
visible light
A group of graduate students, bored during a cloudy night at the observatory, begin to make bets about
the time different stars will take to evolve. If they have a cluster of stars which were all born at roughly
the same time, and want to know which star will become a red giant first, which of the following stars
should they bet on? - ✔ ✔ a star of about the same mass as our Sun
A handsome, rich, but vain movie star notices that he is starting to age, and consults you as his
astronomy expert, to see if you can find an astronomical way to slow down his aging. Which of the
following strategies would IN THEORY allow him to age more slowly than the rest of humanity. - ✔ ✔
he should travel to a black hole, and spend some time in orbit just above the event horizon
A member of the college football team wants to weigh as much as possible. Assuming he could
somehow survive on all of them, at the surface of which object would he weigh the most? - ✔ ✔ a
neutron star
A science fiction writer needs an environment for her latest story where stars are as crowded together
as possible. Which of the following would be a good place to locate her story? - ✔ ✔ in a globular
cluster
A star with a mass like the Sun which will soon die is observed to be surrounded by a large amount of
dust and gas -- all material it has expelled in the late stages of its life. If astronomers want to observe the
radiation from such a giant star surrounded by its own debris, which of the following bands of the
spectrum would be the best to use to observe it? - ✔ ✔ infrared
A type of star cluster that contains mostly very old stars is - ✔ ✔ a globular star cluster
A white dwarf, compared to a main sequence star with the same mass, would always be: - ✔ ✔
smaller in diameter
According to Einstein's general theory of relativity, the stronger a star's gravity, - ✔ ✔ the slower
time runs near it
According to the general theory of relativity, the presence of mass - ✔ ✔ causes a curvature (or
warping) of spacetime
, After a supernova event, the remaining core of the star may become a... - ✔ ✔ neutron star
After it experiences a "helium flash" a star like the Sun will have a brief period of stability, fusing helium
into carbon (and sometimes oxygen). During this brief stable stage, the star - ✔ ✔ none of these
After the core of a massive star becomes a neutron star, the rest of the star's material - ✔ ✔
explodes outward as a supernova
An astronomy student, for her PhD, really needs to estimate the age of a cluster of stars. Which of the
following would be part of the process she would follow? - ✔ ✔ plot an H-R diagram for the stars in
the cluster
As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of
the H-R diagram first? - ✔ ✔ the O and B type stars
As a star becomes a giant, its outer layers are expanding. Where does the energy for expanding these
layers come from? - ✔ ✔ from the fusion of hydrogen into helium in a shell around the core
Astronauts falling into a black hole would not notice anything special happening as they fell through the
Schwarzschild radius. Watching from the outside, we would see the astronauts - ✔ ✔ appear to get
closer and closer to the Schwarzschild radius, but never arrive there.
Astronomer have concluded that pulsars are - ✔ ✔ rotating neutron stars
Astronomers believe that the many supernova explosions that happened in the Milky Way Galaxy could
have played a role in the evolution of life over billions of years. How would they have influenced the
development of life on Earth? - ✔ ✔ the cosmic rays produced by supernova explosions would have
contributed to the rate of mutations over many generations
Astronomers have discovered pulsars spinning 500 x per second or more. How do astronomers think
pulsars got to be spinning so outrageously fast? - ✔ ✔ Such fast-spinning pulsars have companion
stars near them, which dump material on the pulsar and that spins it faster and faster
Astronomers have noticed that the visible filaments in the Crab Nebula are moving toward us at great
speed. How can they know about motions like this? - ✔ ✔ from the Doppler shift in the line radiation
from the nebula
Astronomers observe a young cluster of stars, where stars with three times the mass of the Sun are still
on the main sequence of the H-R diagram. Yet the cluster contains two white dwarfs, each with a mass
less than 1.4 times the mass of the Sun. If we can show that the white dwarfs are definitely part of the
cluster, how can their presence so soon in the life of the cluster be explained? - ✔ ✔ some stars can
lose a lot of mass on their way to becoming white dwarfs; thus the white dwarfs could have started out
as quite massive stars
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