The water coming off comet 3I/ATLAS is not just unusual. It is extreme. Astronomers studying the interstellar comet found that its water is packed with an unusually heavy form of hydrogen called deuterium. The levels are far beyond anything measured in comets from our own solar system. That chemical fingerprint points to a birthplace much colder than the one that produced Earth. It is also colder than the places that formed the planets and the icy bodies that still circle the Sun. The result gives researchers one of their clearest looks yet at how different other planetary systems can be. “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 study and a doctoral student in the University of Michigan’s Department of Astronomy. Astronomers studying the interstellar comet found that its water is packed with an unusually heavy form of hydrogen called deuterium. (CREDIT: Hans Anderson, Michigan …