Astronomy current events question: Milky Way-Andromeda collision data

Astronomy 210L, spring semester 2019
Cuesta College, San Luis Obispo, CA

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

Roeland P. van der Marel, Mark Fardal, Ekta Patel, Timo Prusti, and Markus Bauer, "Gaia Clocks New Speeds for Milky Way-Andromeda Collision" (February 8, 2019)
esa.int/About_Us/ESAC/Gaia_clocks_new_speeds_for_Milky_Way-Andromeda_collision

The European Space Agency's Gaia satellite measured __________ within neighboring galaxies to refine predictions of how they will eventually collide and merge with our Milky Way galaxy.
(A) dark matter.
(B) gravitational waves.
(C) hydrogen superbubbles.
(D) star positions and motions.
(E) supermassive black hole masses.

Correct answer: (D)

Student responses
Sections 30679, 30680
(A) : 2 students
(B) : 5 students
(C) : 4 students
(D) : 19 students
(E) : 2 students