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2006 · Klemperer — Interstellar chemistry

Original title: Interstellar chemistry.

Super-Abstract

This theoretical review discusses the molecular chemistry of the interstellar medium, including the role of molecular hydrogen (H₂) and helium ionisation in driving the rich organic chemistry observed in galaxies. It is an astrophysics overview with no connection to biological or health-related applications of H₂.

Classified as a Review / Meta-analysis study using Unspecified. See Methodology for how we grade evidence.

Commentary

This paper is an editorial overview for a special PNAS issue on interstellar molecular chemistry. It discusses how radioastronomy has revealed a rich inventory of organic molecules in space, and outlines key processes: ionisation of abundant H₂ and atomic helium, secondary reactions, kinetic schemes governing molecular transformations, and the role of grain surfaces in interstellar chemistry. The molecular hydrogen discussed is purely an astrophysical species — the most abundant molecule in the universe — participating in interstellar ion-molecule reactions. There is absolutely no biological, medical, or nutritional dimension to this paper. It is included in this database presumably because it is indexed under hydrogen-related search terms.

Key quotes

  1. „Ionization of the very abundant molecular hydrogen and atomic helium followed by their secondary reactions is discussed.“ — H₂ here is an astrophysical molecule, not a biological agent
  2. „The rich variety of organic species observed is a challenge for complete understanding.“ — the complexity of interstellar organic chemistry
  3. „The role and nature of reactions involving grain surfaces as well as new spectroscopic observations of interstellar and circumstellar regions are topics presented in this special feature.“ — scope of the astrophysics special issue

Our assessment

This is an astrophysics review with no relevance whatsoever to biological effects of molecular hydrogen. H₂ appears only as the most abundant molecule in the universe, playing a role in interstellar ion-molecule chemistry. This paper provides no evidence of any kind regarding H₂ as a health or therapeutic agent.

Study design

Abstract

In the past half century, radioastronomy has changed our perception and understanding of the universe. In this issue of PNAS, the molecular chemistry directly observed within the galaxy is discussed. For the most part, the description of the molecular transformations requires specific kinetic schemes rather than chemical thermodynamics. Ionization of the very abundant molecular hydrogen and atomic helium followed by their secondary reactions is discussed. The rich variety of organic species observed is a challenge for complete understanding. The role and nature of reactions involving grain surfaces as well as new spectroscopic observations of interstellar and circumstellar regions are topics presented in this special feature.

Source & links

Screenshot of the PubMed page

Screenshot — PubMed 16894148

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