View source for Radcliffe wave

{{Use dmy dates|date=January 2020}}
{{Short description|Coherent, wave-shaped gaseous structure in the Milky Way}}
[[File:RadcliffeWave1.png|350px|thumb|The approximate outline of the Radcliffe wave in Earth's night sky]]
The '''Radcliffe wave''' is a neighbouring coherent gaseous structure in the [[Milky Way]], dotted with a related high concentration of interconnected [[Stellar nursery|stellar nurseries]]. It stretches about 8,800 light years.<ref name="theguardian-sample">{{cite news|access-date=7 January 2020|title=Astronomers discover huge gaseous wave holding Milky Way's newest stars|url=https://www.theguardian.com/science/2020/jan/07/astronomers-discover-huge-gaseous-wave-holding-milky-ways-newest-stars|newspaper=The Guardian|date=7 January 2020|issn=0261-3077}}</ref><ref name="bbc">{{cite news|first1=Paul|last1=Rincon|access-date=7 January 2020|title=Vast 'star nursery' region found in our galaxy|url=https://www.bbc.com/news/science-environment-51021704|date=7 January 2020|website=BBC News}}</ref> This structure runs with the trajectory of the [[Milky Way]] arms.<ref>{{cite web|last1=Brandon|first1=Specktor|date=7 January 2020|access-date=7 January 2020|title=Mysterious 'Wave' of Star-Forming Gas May Be the Largest Structure in the Galaxy|url=https://www.livescience.com/radcliffe-wave-largest-milky-way-structure.html|website=livescience.com}}</ref><ref name=":0" />

It lies at its closest (the [[Taurus Molecular Cloud]]) at around 400 [[light-year]]s and at its farthest about 5,000 light-years (the [[Cygnus X (star complex)|Cygnus X]] star complex) from the [[Sun]], always within the [[Orion Arm|Local Arm (Orion Arm)]] itself, spanning about 40% of its length and on average 20% of its width.<ref>{{cite web|last1=Brandon|first1=Specktor|date=7 January 2020|access-date=7 January 2020|title=Mysterious 'Wave' of Star-Forming Gas May Be the Largest Structure in the Galaxy|url=https://www.livescience.com/radcliffe-wave-largest-milky-way-structure.html|website=livescience.com}}</ref><ref name=":0" /> Its discovery was announced in January 2020, and its proximity surprised astronomers.<ref name="theguardian-sample"/><ref name="newsweek">{{cite web|first1=Hannah|last1=Osborne|title=Something appears to have collided with the Milky Way and created a huge wave in the galactic plane|url=https://www.newsweek.com/milky-way-huge-wave-collision-1480799|date=7 January 2020|website=Newsweek}}</ref>

== Formation ==
{{Cleanup colors|date=May 2022}}
<imagemap>
Image:Orion Arm.JPG|frame|center|A clickable map of the nearby circa one-sixth outer sector of the galaxy, thus clearly showing the Local Arm (Orion Arm) and neighboring arms - as well as the [[Great Orion Nebula]] (as a very luminous feature of the less bright [[Orion molecular cloud complex]]) and broad-clouds [[North America Nebula]] (and [[Pelican Nebula]]) which is an intrinsic part of the Radcliffe wave.

rect 126 149 188 182 [[Rosette Nebula]]
rect 285 116 327 145 [[Crab Nebula]]
rect 243 245 284 274 [[Orion Nebula]]
rect 299 288 345 312 [[Trifid Nebula]]
rect 343 304 384 333 [[Lagoon Nebula]]
rect 393 322 434 353 [[Omega Nebula]]
rect 445 322 494 353 [[Eagle Nebula]]
rect 424 244 483 280 [[North America Nebula]]
rect 293 248 319 266 [[Rigel]]
rect 225 179 299 246 [[Orion's Belt]]
rect 331 211 368 234 [[Polaris]]
rect 318 236 353 259 [[Sun]]
poly 302 176 303 241 315 242 361 177 [[Betelgeuse]]
rect 419 222 458 245 [[Deneb]]
poly 0 123 508 118 637 160 637 217 470 163 0 178 [[Perseus Arm]]
poly 2 202 460 201 633 261 637 326 408 260 1 258 [[#Interactive maps|Orion Arm]]
poly 1 284 397 293 633 360 637 477 541 475 357 413 0 400 [[Sagittarius Arm]]

desc bottom-left
</imagemap>
Scientists do not know how the undulation of dust and gas formed. It has been suggested that it could be a result of a much smaller galaxy [[Impact event|colliding]] with the Milky Way, leaving behind "ripples", or could be related to [[dark matter]].<ref name="theguardian-sample"/><ref>{{Cite web|url=https://www.radcliffe.harvard.edu/news/in-news/something-appears-have-collided-milky-way-and-created-huge-wave-in-galactic-plane|title=Something Appears to Have Collided with the Milky Way and Created a Huge Wave in the Galactic Plane|date=2020-01-08|website=Radcliffe Institute for Advanced Study at Harvard University|language=en|access-date=2020-01-09}}</ref> Inside the dense clouds, gas can be so compressed that new [[stars]] are born.<ref name="bbc"/> It has been suggested that this may be where the [[Sun]] originated.<ref name="theguardian-sample"/>

Many of the star-forming regions found in the Radcliffe wave were thought to be part of a similar-sized but somewhat helio-centric ring which contained the [[Solar System]], the "[[Gould Belt]]".  It is now understood the nearest discrete relative concentration of sparse [[interstellar medium|interstellar matter]] instead forms a massive wave.<ref name="theguardian-sample"/><ref name="bbc"/>

== Discovery ==
The wave was discovered by an international team of astronomers including Catherine Zucker and João Alves.<ref>{{cite web|first1=Bennett|last1=McIntosh|access-date=7 January 2020|title=An Interstellar Ribbon of Clouds in the Sun's Backyard|url=https://harvardmagazine.com/2020/01/intergalactic-radcliffe-wave|date=7 January 2020|website=Harvard Magazine}}</ref><ref name=":0" /> It was announced by co-author [[Alyssa A. Goodman]] at the 235th meeting of the [[American Astronomical Society]], held at Honolulu<ref name="cnn-strickland">{{cite web|first1=Ashley|last1=Strickland|access-date=7 January 2020|title=Astronomers discover giant wave-shaped structure in the Milky Way|url=https://www.cnn.com/2020/01/07/world/new-milky-way-map-scn/index.html|work=CNN|date=7 January 2020 }}</ref> and published in the journal ''[[Nature (journal)|Nature]]'' on 7 January 2020.<ref>{{cite web|access-date=7 January 2020|title=New map of Milky Way reveals giant wave of stellar nurseries|url=https://phys.org/news/2020-01-milky-reveals-giant-stellar-nurseries.html|website=Phys.org}}</ref> The discovery was made using data collected by the [[European Space Agency]]'s ''[[Gaia (spacecraft)|Gaia]]'' space observatory.<ref name="AP via JT">{{cite news|last=Dunn|first=Marcia|url=https://www.japantimes.co.jp/news/2020/01/08/world/science-health-world/titanic-wave-star-forming-gases-found-milky-way/|title=Titanic wave of star-forming gases found in Milky Way|date=8 January 2020|agency=Associated Press|access-date=8 January 2020|issn=0447-5763|via=Japan Times Online}}</ref> 

The wave was invisible in [[2D computer graphics|2D]], requiring new [[3D computer graphics|3D]] techniques of mapping interstellar matter to reveal its pattern using [[Glue (software)]].<ref name="bbc"/><ref name="AP via JT"/><ref name="cnn-strickland"/> The proximity of the wave surprised astronomers.<ref name="theguardian-sample"/><ref name="newsweek"/> It is named after the [[Radcliffe Institute for Advanced Study]] in [[Cambridge, Massachusetts]], the place of study of the team.<ref name="AP via JT"/>

== Structure and movement ==
The Radcliffe wave contains four of the five [[Gould Belt]] clouds:
*[[Orion molecular cloud complex]]
*[[Perseus molecular cloud]]
*[[Taurus molecular cloud]]
*[[Cepheus OB2]]

The cloud not within its scope is the [[Rho Ophiuchi cloud complex|Rho Ophiuchi Cloud complex]], part of a linear structure parallel to the Radcliffe wave.

Other structures in the wave, further from the local star system, are [[Canis Major OB1]], the [[North America Nebula]] and [[Cygnus X (star complex)|Cygnus X]].<ref name=":0">{{cite journal|last1=Alves|first1=João|last2=Zucker|first2=Catherine|last3=Goodman|first3=Alyssa A.|last4=Speagle|first4=Joshua S.|last5=Meingast|first5=Stefan|last6=Robitaille|first6=Thomas|last7=Finkbeiner|first7=Douglas P.|last8=Schlafly|first8=Edward F.|last9=Green|first9=Gregory M.|date=January 2020|title=A Galactic-scale gas wave in the Solar Neighborhood|journal=Nature|language=en|volume=578|issue=7794|pages=237–239|arxiv=2001.08748|doi=10.1038/s41586-019-1874-z|pmid=31910431|bibcode=2020Natur.578..237A}}</ref>

The mass of this structure is on the scale of <math>\geq3\times10^6</math> {{Solar mass|link=true}}. It has a length of 8,800 [[light-year]]s (2,700 [[parsec]]s) and an amplitude of 520 [[light-year]]s (160 parsecs). The Radcliffe wave occupies about 20% of the width and 40% of the length of the [[Orion Arm|local arm (Orion Arm)]]. The latter is more dispersed as to its [[interstellar medium]] than the wave and has further large star-forming regions such as [[Monoceros OB1]], [[California Nebula]], Cepheus Far, and [[Rho Ophiuchi cloud complex|Rho Ophiuchi]].<ref name=":0" />

A 2024 paper announced the discovery that the Radcliffe wave is oscillating in the form of a [[traveling wave]].<ref>{{cite journal |first1=Ralf |last1=Konietzka |first2=Alyssa A. |last2=Goodman |first3=Catherine |last3=Zucker |first4=Andreas |last4=Burkert |first5=João |last5=Alves |first6=Michael |last6=Foley |first7=Cameren |last7=Swiggum |first8=Maria |last8=Koller |first9=Núria |last9=Miret-Roig |title=The Radcliffe Wave is Oscillating |journal=[[Nature (journal)|Nature]] |doi=10.1038/s41586-024-07127-3 |date=20 February 2024|volume=628 |issue=8006 |pages=62–65 |pmid=38378142 |arxiv=2402.12596 }}</ref>

==See also==
*[[Antlia 2]], another giant ripple across the Milky Way's disc found in data from the Gaia space telescope
*[[List of nearby stellar associations and moving groups]]
*[[Great Rift (astronomy)]]
*[[Serpens-Aquila Rift]]

==References==
{{Reflist}}

==Further reading==

*{{cite journal|pages=237–239|arxiv=2001.08748|doi=10.1038/s41586-019-1874-z|pmid=31910431|bibcode=2020Natur.578..237A|title=A Galactic-scale gas wave in the solar neighborhood|journal=Nature|volume=578|year=2020|last1=Alves|first1=João|last2=Zucker|first2=Catherine|last3=Goodman|first3=Alyssa A.|last4=Speagle|first4=Joshua S.|last5=Meingast|first5=Stefan|last6=Robitaille|first6=Thomas|last7=Finkbeiner|first7=Douglas P.|last8=Schlafly|first8=Edward F.|last9=Green|first9=Gregory M.|issue=7794}}

==External links==
*[http://worldwidetelescope.org/webclient/?tourUrl=https%3A%2F%2Ffaun.rc.fas.harvard.edu%2Fczucker%2FPaper_Figures%2FRadWave_AAS_Sky.WTT Interactive map of the Radcliffe wave on the sky]
*[https://sites.google.com/cfa.harvard.edu/radcliffewave/ The Radcliffe Wave] informational site created by Harvard University

{{2020 in space}}

[[Category:Star formation]]
[[Category:Stellar astronomy]]
[[Category:Star-forming regions]]
[[Category:Milky Way]]
[[Category:Astronomical objects discovered in 2020]]