Atoms and Molecules in Space

H3 then becomes reactive with HD to produce H2D and H2 (note the same reaction of H3 with H2 regenerates H3 ). Defying normal intuition, the consequences of this chemistry suggest that the relative abundance of related isotopic species in these environs is H3 H2D D2ff D3% totally the reverse of the natural isotopic abundances. These species can react with other molecules to produce the enrichment noted for deuter-ated species. 

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Radio astronomy uses a radio telescope to receive and study radio waves naturally emitted by objects in space. Radio waves are emitted from hot gases (thermal radiation), from charged particles spiraling in magnetic fields (synchrotron radiation), and from excited atoms and molecules in space (spectral lines), such as the 21-cm line emitted by hydrogen gas. 

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