[rayiner]

The question as it's worded is: "does the earth go around the sun or does the sun go around the earth?" There's all sorts of reasons someone might get that question wrong. The way it's framed makes you visualize two systems and pick the right one, and people might have a problem with that. The phrasing depends on word order being significant in English in ways that might be confusing to foreign language speakers (of which the U.S. has many). Heck, just parsing it took me enough time that someone rushing through the survey might just not think about it too carefully before answering.

I bet if you showed two pictures, with a large sun orbiting the earth and one with a small earth orbiting a large sun, you'd get a much higher percentage right.