Less than a year ago, astronomers discovered a comet soaring through our sky that was not from our solar system. Although we still don’t know where this interstellar object called 3I/ATLAS came from, research led by the University of Michigan has revealed new insights about its birthplace. Wherever that was, it was much colder than the environment that created our solar system.

The new finding is based on the observation that 3I/ATLAS is remarkably rich in a specific type of water that contains deuterium. The team’s study is published in the journal Nature Astronomy.

“Our new observations show that the conditions that led to the formation of our solar system are much different from how planetary systems evolved in different parts of our galaxy,” said Luis Salazar Manzano, lead author of the new study and a doctoral student in the U-M Department of Astronomy.