Astronomy current events question: Tyche evidence

Astronomy 210L, Spring Semester 2011
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!)

Phil Plait, "No, There’s No Proof of a Giant Planet in the Outer Solar System," February 14, 2011
http://blogs.discovermagazine.com/badastronomy/2011/02/14/no-theres-no-proof-of-a-giant-planet-in-the-outer-solar-system/#more-28256

Two astronomers recently announced Tyche, a Jupiter-sized planet out beyond Pluto, based on:
(A) observations from NASA's Wide-field Survey Explorer.
(B) analysis of perturbations on Jupiter's orbit.
(C) estimating the gravity required to affect long-period comets.
(D) decoding ancient Egyptian astronomical records.
(E) studying systematic errors in astrological horoscopes.

Correct answer: (C)

Student responses
Sections 30678, 30679, 30680
(A) : 23 students
(B) : 11 students
(C) : 18 students
(D) : 0 students
(E) : 3 students