Editing Absorption spectroscopy (section)

===Astronomy===
[[File:Cumulative-absorption-spectrum-hubble-telescope.jpg|thumb|upright=2|Absorption spectrum observed by the [[Hubble Space Telescope]]]]

[[Astronomical spectroscopy]] is a particularly significant type of remote spectral sensing. In this case, the objects and samples of interest are so distant from earth that electromagnetic radiation is the only means available to measure them. Astronomical spectra contain both absorption and emission spectral information. Absorption spectroscopy has been particularly important for understanding [[interstellar cloud]]s and determining that some of them contain [[molecular cloud|molecules]]. Absorption spectroscopy is also employed in the study of [[exoplanet|extrasolar planets]]. Detection of extrasolar planets by [[methods of detecting exoplanets#Transit photometry|transit photometry]] also measures their absorption spectrum and allows for the determination of the planet's atmospheric composition,<ref name="Khd">{{cite journal |last1=Khalafinejad |first1=S. |last2=Essen |first2=C. von |last3=Hoeijmakers |first3=H. J. |last4=Zhou |first4=G. |last5=Klocová |first5=T. |last6=Schmitt |first6=J. H. M. M. |last7=Dreizler |first7=S. |last8=Lopez-Morales |first8=M. |last9=Husser |first9=T.-O. |date=2017-02-01 |title=Exoplanetary atmospheric sodium revealed by orbital motion |journal=Astronomy & Astrophysics |language=en |volume=598 |pages=A131 |doi=10.1051/0004-6361/201629473 |issn=0004-6361 |arxiv=1610.01610 |bibcode=2017A&A...598A.131K |s2cid=55263138}}</ref> temperature, pressure, and [[scale height]], and hence allows also for the determination of the planet's mass.<ref>{{cite journal |last=de Wit |first=Julien |author2=Seager, S. |title=Constraining Exoplanet Mass from Transmission Spectroscopy |journal=Science |date=19 December 2013 |volume=342 |issue=6165 |pages=1473–1477 |doi=10.1126/science.1245450 |arxiv=1401.6181 |bibcode=2013Sci...342.1473D |pmid=24357312 |s2cid=206552152}}</ref>