Editing Polarization (waves) (section)

=== Astronomy ===
{{Main|Polarization in astronomy}}
In many areas of [[astronomy]], the study of polarized electromagnetic radiation from [[outer space]] is of great importance. Although not usually a factor in the [[thermal radiation]] of [[star]]s, polarization is also present in radiation from coherent [[astronomical source]]s (e.g. hydroxyl or methanol [[maser]]s), and incoherent sources such as the large radio lobes in active galaxies, and pulsar radio radiation (which may, it is speculated, sometimes be coherent), and is also imposed upon starlight by scattering from [[interstellar dust]]. Apart from providing information on sources of radiation and scattering, polarization also probes the interstellar magnetic field via [[Faraday rotation]].<ref>{{cite journal|last=Vlemmings|first=W. H. T.|title=A review of maser polarization and magnetic fields|journal=Proceedings of the International Astronomical Union|volume=3|issue=S242|pages=37–46|date=Mar 2007|doi=10.1017/s1743921307012549 |doi-access=free |arxiv = 0705.0885 |bibcode=2007IAUS..242...37V  |bibcode-access=free}}</ref>{{rp|119,124}}<ref name="KarttunenKröger2007">{{cite book|author1=Hannu Karttunen|author2=Pekka Kröger|author3=Heikki Oja|title=Fundamental Astronomy|date=27 June 2007|publisher=Springer|isbn=978-3-540-34143-7}}</ref>{{rp|336–337}} The polarization of the [[cosmic microwave background radiation|cosmic microwave background]] is being used to study the physics of the very early universe.<ref name="boyle">{{cite journal|journal=Physical Review Letters|volume=96|date=2006|pages=111301|first1=Latham A.|last1=Boyle|title=Inflationary predictions for scalar and tensor fluctuations reconsidered|doi=10.1103/PhysRevLett.96.111301|pmid=16605810|last2=Steinhardt|first2=PJ|last3=Turok|first3=N|issue=11|arxiv=astro-ph/0507455 |bibcode=2006PhRvL..96k1301B|s2cid=10424288}}</ref><ref name="tegmark">{{cite journal|first=Max|last=Tegmark|title=What does inflation really predict? |doi=10.1088/1475-7516/2005/04/001|journal=Journal of Cosmology and Astroparticle Physics|volume=0504|issue=4|pages=001|date=2005|arxiv=astro-ph/0410281|bibcode=2005JCAP...04..001T|s2cid=17250080}}</ref> [[Synchrotron radiation]] is inherently polarized. It has been suggested that astronomical sources caused the [[chirality]] of biological molecules on Earth,<ref>{{cite journal |last=Clark |first=S. |date=1999 |title=Polarised starlight and the handedness of Life |journal=American Scientist |volume=97 |issue=4 |pages=336–43 |doi=10.1511/1999.4.336 |bibcode=1999AmSci..87..336C|s2cid=221585816 }}</ref> but chirality selection on inorganic crystals has been proposed as an alternative theory.<ref>{{Cite journal |last1=Hazen |first1=Robert M. |last2=Sholl |first2=David S. |date=2003-06-01 |title=Chiral selection on inorganic crystalline surfaces |url=https://www.nature.com/articles/nmat879 |journal=Nature Materials |language=en |volume=2 |issue=6 |pages=367–374 |doi=10.1038/nmat879 |pmid=12776102 |bibcode=2003NatMa...2..367H |issn=1476-1122}}</ref>