Does the sun change shape? Up until recently scientists believed that it did. It was presumed that the shape of the giant star changed with each of its 11-year solar cycles, when its surface has been known to rise and fall dramatically. However, the results of a two-year study conducted using NASA's Solar Dynamic Observatory show that the sun's shape doesn't vary much at all. 

They study also showed that the sun is flatter, but also much rounder than previously thought. 

"The peculiar fact that the sun is slightly too round to agree with our understanding of its rotation is also an important clue in a longstanding mystery," said Jeffery Kuhn, a physicist at the University of Hawaii in Pukalani, who was the lead researcher for the study.

"The fact that it is too round means that there are other forces at work making this round shape. We've probably misunderstood how the gas turbulence in the sun works, or how the sun organizes the magnetism that we can only see at the surface. Finding problems in our theories is always more exciting than not, since this is the only way we learn more."

NASA is currently working on new tools to better determine "how oscillations from deep in the sun's interior are manifested at its surface." 

[via Space]