The shape of our galaxy may reveal a history of collisions with other galaxies or even galactic clusters.

New measurements suggest that the Milky Way galaxy may have a different shape than we thought.

Over the past few years, astronomers have increasingly discovered that galaxies seem to come in three main shapes: Elliptical, irregular and spiral. The majority of known galaxies that fit in this last category seem to have two prominent "arms" that branch out and split into lesser arms.

But the traditional portrayal of the Milky Way is that of a galaxy with four major spiral arms extending out from a thick centralized bulge of stars. This makes our spiral galaxy stand out as an extremely rare outlier with an odd shape that must have some very unique properties to grant it four major arms.

That portrayal could be wrong, however. A team of astronomers has published new research that suggests we have been wrong about the shape of the Milky Way for decades, with our galaxy instead having two main arms just like its contemporary spiral galaxies.