Scientists are baffled at the intriguing pattern of butterfly-shaped planetary nebulae observed in the Milky Way.

Hydrogen fuel runs out in a star's core by the late stages of its life. As a result, the star's outer layers are "puffed out" into the surrounding space which then creates shapes and features. These created shapes and features are called planetary nebulae.

According to the International Business Times, planetary nebulae are basically clouds of gas. They can come in various shapes -- with some assuming the shape of an hourglass. However, scientists have found out that shapes and features of planetary nebulae can be classified into three types.

About 130 planetary nebulae in the Milky Way's central bulge were observed for the study. The study was published in Monthly Notices of the Royal Astronomical Society. The three classifications that scientists and astronomers were able to defer through the observation are: (1) bipolar, (2) elliptical and (3) with or without an aligned structure.

Through the use of the Hubble Space Telescope and the European Southern Observatory's New Technology Telescope (NTT), the University of Manchester's astronomers were able to discover a "bizarre alignment" among planetary nebulae. Specifically, the bipolar planetary nebulae were all aligned in the same manner.

"The alignment we're seeing for these bipolar nebulae indicates something bizarre about star systems within the central bulge. For them to line up in the way we see, the star systems that formed these nebulae would have to be rotating perpendicular to the interstellar clouds from which they formed, which is very strange," says Bryan Rees of the University of Manchester in a report by the National Monitor.

According to Albert Zijlstra, one of the astronomers involved in the study, the other two classifications of planetary nebulae were "completely randomly aligned in the sky, as expected." The bipolar planetary nebulae, on the other hand, showed a "surprising preference" and were even crowded in the central region or the central bulge of the Milky Way.

This led astronomers to believe that the central bulge may have a bigger influence over the Milky Way through its magnetic fields.

"We can learn a lot from studying these objects. If they really behave in this unexpected way, it has consequences for not just the past of individual stars, but for the past of our whole galaxy," says Zijlstra.