How are rotation curves of spiral galaxies determined for distances beyond where starlight can be detected?
A) by measuring the broadening of the galaxy's absorption lines
B) by extrapolation of the measured rotation curve
C) by observations of spectral lines emitted by dark matter
D) by watching the galaxies rotate over a period of decades
E) by observations of the 21 cm line of atomic hydrogen
E
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In a simple-cubic lattice, the interstitial atoms are positioned at the coordinates _____________.
Fill in the blank(s) with the appropriate word(s).
Which of the following is the largest distance?
A) diameter of a typical galaxy B) diameter of Pluto's orbit C) distance to the nearest star (other than our Sun) D) 1 light-year
The interrelationship among the processes that produce the three classes of rock is referred to as
a. the rock cycle. b. the bedding principle. c. the principle of cross-cutting relationships. d. metamorphism.
What information about orbital inclination can we get from visual binaries, spectroscopic binaries, and eclipsing binaries?
What will be an ideal response?