For the past 30 years,the significance of the anomalously low ortho-to-para ratios (OPRs) of gaseous water (H2O) in interstellar space has remained unknown. (In ortho hydrogen molecules, both nuclei spin in the same direction, and while in para hydrogen the nuclei spin opposite directions.) Recently,however, scientists at Hokkaido University, or Sapporo,Japan found that water desorbed (that is, released from or through a surface) from ice at 10 kelvin shows a statistical high temperature OPR of 3 rather than the lower values typically found, and even when the ice is produced in situ by a known formation process of interstellar water known as O2 hydrogenation. This invalidates the assumed relation between OPR and temperature and requires a reinterpretation of the low OPRs will abet elucidate the chemical history of interstellar water from molecular clouds and processes in the early solar system,including comet formation.
Source: phys.org