Kosmochemia

Kosmochemia, or cosmochemistry, is the scientific study of the chemical composition of matter in the universe and the processes that govern the distribution of elements and isotopes from the origin of the cosmos to the present. It integrates astronomy, geology, chemistry, and physics to understand how cosmic materials form and transform, from stellar nucleosynthesis to planetary differentiation.

The field examines a wide range of objects and materials, including stars, the interstellar medium, comets, asteroids, meteorites, and planetary atmospheres. Key questions focus on elemental abundances, isotopic ratios, and the origin of water and volatile compounds on planets. Measurements come from astronomical spectroscopy, laboratory analysis of extraterrestrial samples, and spacecraft missions.

Core methods involve mass spectrometry to determine precise isotopic compositions, radiometric dating to establish ages, and spectroscopy across ultraviolet, visible, and infrared wavelengths. Cosmochemists use data from meteorites, returned samples, and remote sensing of planetary bodies to infer nucleosynthetic histories and solar system formation conditions.

The field contributes to understanding nucleosynthesis in stars, the chemical evolution of the galaxy, and the early solar system, including refractory inclusions and chondrules in meteorites and the sources of Earth's volatiles. It often overlaps with planetary science, astrochemistry, and meteoritics.

Challenges include interpreting mixed signatures, contamination, and the effects of parent-body processing. Ongoing space missions, improved analytical techniques, and sample-return programs continue to refine our picture of cosmic chemical evolution.