Astronomy current events question: mass of Andromeda galaxy

Astronomy 210L, spring semester 2018
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!)

Prajwal Kafle and Pete Wheeler, "Milky Way Ties with Neighbour in Galactic Arms Race" (February 15, 2018)
icrar.org/cosmic-collision/

From measuring the orbits of its high speed stars, the Andromeda galaxy's mass is determined to be:
(A) nearly all dark matter.
(B) more dense than antimatter.
(C) slowly increasing over time.
(D) concentrated in its central supermassive black hole.
(E) comparable to our Milky Way galaxy.

Correct answer: (E)

Student responses
Sections 30679, 30680
(A) : 2 students
(B) : 2 students
(C) : 3 students
(D) : 3 students
(E) : 28 students