Astronomy current events question: PG 1302-102 merging black holes

Astronomy 210L, fall semester 2015
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!)

Whitney Clavin, "Funky Light Signal From Colliding Black Holes Explained" (September 16, 2015)
nasa.gov/feature/jpl/funky-light-signal-from-colliding-black-holes-explained

Historical variations in __________ observed by NASA's Galaxy Evolution Explorer and NASA's Hubble Space Telescope indicate that PG 1302-102 may be a close-knit pair of merging black holes.
(A) ultraviolet light.
(B) gravity waves.
(C) time dilation.
(D) neutrino emission.
(E) matter-antimatter ratios.

Correct answer: (A)

Student responses
Sections 70178, 70186
(A) : 18 students
(B) : 7 students
(C) : 2 students
(D) : 2 students
(E) : 3 students