Chapter 14 Flashcards
Why do disk stars bob up and down as they orbit the galaxy?
because the gravity of other disk stars always pulls them toward the disk
Which part of the galaxy has gas with the hottest average temperature?
the halo
What is the typical hydrogen content of stars that are forming right now in the vicinity of the Sun?
70% hydrogen
Why are the ionization nebulae so bright?
They are regions where gas is ionized by hot, young stars.
Which of these forms of radiation passes most easily through the disk of the Milky Way?
infrared light
The Sun’s velocity around the Milky Way tells us that most of our galaxy’s dark matter lies near the center of the galactic disk.
false
Halo stars orbit the center of our galaxy much faster than the disk stars.
false
Where are most of the Milky Way’s globular clusters found?
in the halo
How do we determine the Milky Way’s mass outside the Sun’s orbit?
from the orbits of stars and gas clouds orbiting the galactic center at greater distances than the Sun
Where would you least expect to find an ionization nebula?
in the halo
Where would be the most likely place to find an ionization nebula?
in a spiral arm
Which kind of star is most likely to be part of the spheroidal population?
an O star an A star an Mstar
an M star
We measure the mass of the black hole at the galactic center from
the orbits of stars in the galactic center.
If we could watch a time-lapse movie of a spiral galaxy over millions of years, we’d see many stars being born and dying within the spiral arms.
true
