Astronomy current events question: latest exoplanet discoveries

Astronomy 210L, Fall Semester 2009
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!)

Alan MacRobert, "And Then There Were 400," October 21, 2009
http://www.skyandtelescope.com/news/65056162.html

How did the European Space Observatory in La Silla, Chile detect the 30 newest exoplanets, bringing the known total to over 400?
(A) Reflected radio signals from Voyager 1/2 probes.
(B) Observing these planets passing in front of their stars.
(C) Wobbles these planets exert on their stars.
(D) Laser light reflected off these planets.
(E) Radio signals from planetary magnetic storms.

Correct answer: (C)

Student responses
Sections 70178, 70186, 70200
(A) : 8 students
(B) : 14 students
(C) : 41 students
(D) : 4 students
(E) : 1 student