Why an ‘unexciting’ galaxy could provide clues about the universe’s evolution

NASA and the European Space Agency have released an image captured by the Hubble Space Telescope of a dwarf irregular galaxy that they admit looked “unexciting” at first glance. However, there’s more going on than might initially meet the eye. The agencies say that a great deal of research is going into the “complicated structure” of NGC 5238, which is 14.5 million light-years away in the Canes Venatici constellation. In fact, astronomers believe the distribution of stars in NGC 5238 may have been distorted after it swallowed up another galaxy.

They reckon that due to NGC 5238’s star population (which Hubble is adept at helping to image), it had a “close encounter” with another galaxy perhaps as recently as a billion years ago. But since there isn’t a galaxy close enough to have distorted the star distribution in this fashion, it’s more likely that NGC 5238 merged with a smaller galaxy. Along with hosting many stars, the galaxy is home to globular clusters, which NASA describes as “glowing, bright spots both inside and around the galaxy swarmed by even more stars.”

Astronomers plan to dig deep into the data to learn about NGC 5238’s past. If they find groups of stars that have different properties from most of the galaxy’s other stars, that’s a clear indication that a merger has occurred. They’ll also try to determine whether there was a “burst of star formation” that suddenly took place after the galaxies would have come together.

NASA notes that a dwarf irregular galaxy merging with a smaller satellite galaxy is just the kind of thing that could have spurred galaxy assembly in the early era of our universe. As such, the agency says that the data Hubble captured from NGC 5238 may help researchers to test fundamental ideas about the evolution of the universe.