Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Amorphous Solid

  • William M. Irvine
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_69-3


An amorphous solid lacks long-range order in the positioning of its constituent atoms; glass is an example. This contrasts with a crystalline solid, where such order is present, e.g., quartz. Both the ices and the silicates in interstellar dust grains are typically amorphous, although crystalline silicates are present in some circumstellar and cometary dust. The conversion of amorphous to crystalline water ice has often been invoked as an energy source in cometary outbursts at large heliocentric distances. The presence of crystalline silicates (presumably formed in the hot and dense inner solar system, possibly under the action of energetic particles from the young Sun) in comets, which are formed in the cold outer part of the solar system, suggests that mixing of material was important in the solar nebula.

See Also


Energy Source Bioorganic Chemistry Solar System Outer Part Energetic Particle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of AstronomyUniversity of Massachusetts, Lederle Graduate Research Tower B 619EAmherstUSA