Editing Galactic Center (section)

==Discovery==
[[File:Infrared-visible light comparison of VISTA’s gigapixel view of the centre of the Milky Way.ogv|thumb|upright=1.2|This pan video gives a closer look at a huge image of the central parts of the Milky Way made by combining thousands of images from ESO's [[VISTA (telescope)|VISTA telescope]] on Paranal in Chile and compares it with the view in visible light. Because VISTA has a camera sensitive to infrared light, it can see through much of the dust blocking the view in visible light, although many more opaque dust filaments still show up well in this picture.]]

Because of [[Interstellar cloud|interstellar dust]] along the line of sight, the Galactic Center cannot be studied at [[Visible spectrum|visible]], [[ultraviolet]], or soft (low-energy) [[X-ray]] [[wavelength]]s. The available information about the Galactic Center comes from observations at [[gamma ray]], hard (high-energy) X-ray, [[infrared]], submillimetre, and [[Radio wave|radio]] wavelengths.

[[Immanuel Kant]] stated in ''[[Universal Natural History and Theory of the Heavens]]'' (1755) that a large star was at the center of the [[Milky Way]] galaxy, and that [[Sirius]] might be the star.<ref name="ley196508">{{Cite magazine |last=Ley |first=Willy |date=August 1965 |title=The Galactic Giants |department=For Your Information |url=https://archive.org/stream/Galaxy_v23n06_1965-08#page/n129/mode/2up |magazine=Galaxy Science Fiction |pages=130–142 }}</ref> [[Harlow Shapley]] stated in 1918 that the halo of [[globular cluster]]s surrounding the Milky Way seemed to be centered on the star swarms in the constellation of Sagittarius, but the dark [[molecular cloud]]s in the area blocked the view for optical astronomy.<ref name=shapley>{{cite journal |bibcode=1918ApJ....48..154S |title=Studies based on the colors and magnitudes in stellar clusters. VII. The distances, distribution in space, and dimensions of 69 globular clusters |journal=The Astrophysical Journal |volume=48 |page=154 |last=Shapley |first=H |year=1918 |doi=10.1086/142423|doi-access=free }}</ref> 

In the early 1940s [[Walter Baade]] at [[Mount Wilson Observatory]] took advantage of [[Blackout (wartime)#World War II|wartime blackout]] conditions in nearby Los Angeles, to conduct a search for the center with the {{convert|100|in|cm|adj=on}} [[Hooker Telescope]]. He found that near the star [[Alnasl]] (Gamma Sagittarii), there is a one-degree-wide void in the interstellar dust lanes, which provides a relatively clear view of the swarms of stars around the nucleus of the Milky Way galaxy.<ref name=baade>{{cite journal |bibcode=1946PASP...58..249B |title=A Search for the Nucleus of Our Galaxy |journal=Publications of the Astronomical Society of the Pacific |volume=58 |issue=343 |page=249 |last=Baade |first=W |year=1946 |doi=10.1086/125835}}</ref> This gap has been known as [[Baade's Window]] ever since.<ref name=ng>{{cite journal |bibcode=1996A&A...310..771N |title=The galactic structure towards the Galactic Center. III. A study of Baade's Window: Discovery of the bar population? |journal=Astronomy and Astrophysics |volume=310 |page=771 |last1=Ng |first1=Y. K |last2=Bertelli |first2=G |last3=Chiosi |first3=C |last4=Bressan |first4=A |year=1996}}</ref>

At [[Dover Heights]] in Sydney, Australia, a team of radio astronomers from the Division of Radiophysics at the [[CSIRO]], led by [[Joseph Lade Pawsey]], used "[[sea interferometry]]" to discover some of the first interstellar and intergalactic radio sources, including [[Taurus A]], [[Virgo A]] and [[Centaurus A]]. By 1954 they had built an {{convert|80|ft|m|adj=on}} fixed dish antenna and used it to make a detailed study of an extended, extremely powerful belt of radio emission that was detected in Sagittarius. They named an intense point-source near the center of this belt [[Sagittarius A]], and realised that it was located at the very center of the Galaxy, despite being some 32 degrees south-west of the conjectured Galactic Center of the time.<ref name=pawsey>{{cite journal |bibcode=1955ApJ...121....1P |title=A Catalogue of Reliably Known Discrete Sources of Cosmic Radio Waves |journal=The Astrophysical Journal |volume=121 |page=1 |last=Pawsey |first=J. L |year=1955 |doi=10.1086/145957}}</ref>

In 1958 the [[International Astronomical Union]] (IAU) decided to adopt the position of Sagittarius A as the true zero coordinate point for the system of [[Galactic coordinate system|galactic latitude and longitude]].<ref name=iau>{{cite journal |title=The new IAU system of galactic coordinates (1958 revision) |first1=A. |last1=Blaauw |last2=Gum |first2=C.S. |last3=Pawsey |first3=J.L. |last4=Westerhout |first4=G. |date=1960 |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=121 |issue=2 |pages=123–131 |bibcode=1960MNRAS.121..123B |doi=10.1093/mnras/121.2.123|doi-access=free }}</ref> In the [[equatorial coordinate system]] the location is: [[Right ascension|RA]] {{RA|17|45|40.04}}, [[Declination|Dec]] {{DEC|-29|00|28.1}} ([[J2000]] [[Epoch (astronomy)|epoch]]).

In July 2022, astronomers reported the discovery of massive amounts of [[Abiogenesis#Producing molecules: prebiotic synthesis|prebiotic molecule]]s, including some associated with [[RNA]], in the Galactic Center of the Milky Way galaxy.<ref name="SA-20220708">{{cite news |last=Starr |first=Michelle |title=Loads of Precursors For RNA Have Been Detected in The Center of Our Galaxy |url=https://www.sciencealert.com/scientists-have-found-a-bunch-of-rna-precursors-in-the-galactic-center |date=8 July 2022 |work=[[ScienceAlert]] |access-date=9 July 2022 }}</ref><ref name="FASS-20220708">{{cite journal |author=Rivilla, Victor M. |display-authors=etal |title=Molecular Precursors of the RNA-World in Space: New Nitriles in the G+0.693-0.027 Molecular Cloud |date=8 July 2022 |journal=[[Frontiers in Astronomy and Space Sciences]] |volume=9 |doi=10.3389/fspas.2022.876870 |doi-access=free |arxiv=2206.01053 |bibcode=2022FrASS...9.6870R }}</ref>