Using the Stratospheric Observatory for Infrared Astronomy (SOFIA), a team of astronomers mapped out the magnetic field of G47, one of the Milky Way's galactic bones (dense clouds of gas and dust that run through the middle of the arm of a spiral galaxy). Surprisingly, the map revealed a magnetic field with no clear pattern or direction. The researchers had expected the magnetic field to be similar to the more uniform fields seen in galactic bones in other arms of the Milky Way.
According to the text, what was surprising about the researchers' mapping of the magnetic field of galactic bone G47?
Explanation
Context: Astronomers using SOFIA mapped the magnetic field of G47, one of the Milky Way's galactic bones, and found something they had not expected after studying bones in other arms of the galaxy. The task is to say what surprised them.
Answer: C) It revealed a magnetic field that wasn't uniform.
Why? The map showed "a magnetic field with no clear pattern or direction," the opposite of the "more uniform fields" the researchers had expected based on galactic bones elsewhere in the Milky Way.
Traps:
- A) No earlier mapping of G47 is mentioned, so the result cannot be said to expose errors in past work.
- B) Measurements like those from other galactic bones were the expectation, not the surprise; the surprise was that G47 differed.
- D) The passage characterizes the field's pattern and direction and says nothing about its strength.