HDO/H2O ratio Archives

This artist’s impression compares the semi-heavy water content of the interstellar comet 3I/ATLAS (left) and Earth (right). Insets illustrate the relative abundance of deuterated water (HDO) molecules, showing that 3I/ATLAS contains over 30 times more HDO than is found in Earth’s oceans. This elevated ratio suggests the comet formed in an extremely cold environment, very different from the conditions that shaped our Solar System. Credit: NSF/AUI/NSF NRAO/M.Weiss

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release

ALMA Reveals Interstellar Comet 3I/ATLAS Formed in a Far Colder World Than Our Own

by Keith CowingApril 23, 2026April 23, 2026

New observations from the Atacama Large Millimeter/submillimeter Array (ALMA) have yielded the first-ever measurement of deuterated water — also known as semi-heavy water — in an interstellar object. The discovery […]

HDO/H2O ratio

ALMA Reveals Interstellar Comet 3I/ATLAS Formed in a Far Colder World Than Our Own

ExoClock Unlocked: A Project To Increase Public Participation In Exoplanet Research

Galápagos Hydrothermal Vents Join Third 100 IUGS Geological Heritage Site Listing

Best Bulk Bennu (B3): Elemental Compositions Of Aggregate Samples From Asteroid Bennu K.

The Neptunian Ridge Through The Lens Of TESS

Sulfur Dioxide Sulfide (SSO2): The Elusive Isovalent Analogue of Sulfur Trioxide (SO3)