An interstellar comet known as 3I/ATLAS is expelling water at an extraordinary rate, releasing enough each day to fill 70 Olympic-sized swimming pools, according to recent observations.
The discovery was made using data from the Atacama Large Millimeter Array (ALMA) in Chile, collected shortly after the comet’s closest approach to the Sun. Scientists detected an unusually high concentration of semi-heavy water, a variant where one hydrogen atom contains an extra neutron, known as deuterium.
Research led by Chilean astronomer Tere Paneque, published in Nature Astronomy, found that 3I/ATLAS contains at least 30 times more semi-heavy water than comets in our solar system and 40 times more than Earth’s oceans.
Paneque, who led the data acquisition, reduction, and analysis using ALMA, described the mission as a high-risk endeavor, noting that no previous attempt had measured such molecules in an interstellar object.
The extreme abundance of this heavy water suggests the comet formed in an environment significantly colder than that of our solar system, offering clues about its origins in distant interstellar space.
First detected as the third known interstellar object, 3I/ATLAS continues to display characteristics that set it apart from typical solar system comets, drawing sustained scientific interest.
Its behavior provides a rare opportunity to study material from beyond our planetary system, with implications for understanding the chemical composition of distant star-forming regions.
The findings contribute to ongoing efforts to trace the origins of interstellar visitors and assess what they reveal about the conditions in which they were created.
