Talk:Nebula

Wiki Education Foundation-supported course assignment
This article is or was the subject of a Wiki Education Foundation-supported course assignment. Further details are available on the course page. Student editor(s): Dsdevnull. Peer reviewers: Dsdevnull.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 05:03, 17 January 2022 (UTC)

Listing types
Moving the list here. 


 * Interstellar cloud contains H I, H II, and molecular clouds.
 * H II region / Nebula
 * Emission nebula
 * Reflection nebula
 * Variable nebula, has examples.
 * Dark nebula
 * Bok globule, isolated relatively small patches of dark nebulae.
 * Cometary globule
 * Planetary nebula (PN)
 * Protoplanetary nebula (PPN)
 * Mira - a precursor to a PN? Dust and tail around the Mira stars?
 * Bipolar nebula
 * "Super Planetary Nebula" - from intermediate sized stars.
 * Wolf–Rayet nebula
 * Pinwheel nebula (occurring around WR stars) - spiraling out gas of materials 1st,  2nd,.
 * Nova remnant
 * Supernova remnant (SNR)
 * Pulsar wind nebula (PWN) - a type of nebula inside the shell of a SNR.
 * X-ray Nebula (XRN) - are nebulae that emit x-rays (only in SNR?).
 * Hypernova Remnant - theory so far, but a candidate.


 * Herbig–Haro object (HH) - collision excited nebulae.
 * Accretion disk - can mean several things; circumstellar link.
 * Circumstellar disc - some are protoplanetary discs and some are around mature stars, like white dwarfs.
 * Circumbinary disc
 * - are pre-stellar envelopes.
 * - part of the stellar envelope.
 * Infrared cirrus
 * High-velocity cloud (HVC)
 * Intermediate Velocity Cloud (IVC)
 * Low Velocity Cloud (LVC)
 * Intergalactic Cloud (ie. Smith's Cloud)
 * Dated term:
 * Spiral Nebula (dated, are now determined to be galaxies)
 * , might not exist.

Thanks, Marasama (talk) 23:11, 23 August 2009 (UTC)
 * (I made it multicolumn for the sake of overview ... said: Rursus ( m bork³ ) 10:47, 27 August 2009 (UTC))
 * Cool, thanks, Marasama (talk) 20:45, 29 August 2009 (UTC)
 * Example of a spiral/pinwheel nebula from the star 2XMM J160050.7–514245, - adding as reference, Marasama (talk) 04:23, 20 November 2018 (UTC)

Just adding reference to prepare
Basic info. on nebula. Not the detail items. Still trying to find the history on it and the first nebula discovered. Thanks, Marasama (talk) 18:00, 20 October 2009 (UTC)
 * http://www.haystack.mit.edu/edu/pcr/resources/astronomyhistory.htm
 * http://www.noao.edu/image_gallery/nebulae.html
 * http://seds.lpl.arizona.edu/Messier/nebula.html

History to-do list
This is just a working list of information that could be added to the History section: If you can add some of these in to the article, it would be appreciated. Thanks.&mdash;RJH (talk) 19:38, 1 November 2009 (UTC)
 * The General Catalogue of Nebulae and Clusters of John Herschel, which later became the NGC. John Herschel postulated that that there was sparse matter throughout space that did not glow.
 * Lord Rosse discovers that many of the nebulae have a spiral structure. He and John Herschel were at odds over the nature of nebulae, with Rosse believing they were unresolved clusters of stars. (The contention was related to the theory of evolution, with Rosse not believing that new stars were still forming.)
 * In 1900, Cornelius Easton argued that the Milky Way had a spiral structure and that many of the nebulae formed part of this structure. (This had first been suggested in the middle of the 19th century.)
 * The observations of E. E. Barnard lent weight to the idea that the dark regions of the sky were actually obscuring matter (rather than tunnel-like holes suggested by John Herschel).
 * The 1920 Shapley–Curtis Debate that would lead to the categorization of many nebulae as Island Universes (or galaxies) per Edwin Hubble.
 * Max Wolf was the first person to estimate the distance to interstellar clouds. His approximation compared the number of stars per square degree (and their magnitudes) in a cloud region to elsewhere.
 * In 1927, Herman Zanstra determined how the neutral hydrogen in H II regions became excited.
 * The 1927 explanation by Ira Sprague Bowen of the forbidden lines in the O III spectrum within nebula. (Previously attributed to "nebulium".)
 * The 1953 suggestion of Iosif Shklovsky that the continuum radiation from the Crab Nebula is actually synchrotron radiation.

Question on other types of Nebulae and/or Clouds
What the difference between Nebula and Molecular cloud? Also there are types of Nebulae/Clouds. Talk:Nebula Thanks, Marasama (talk) 15:53, 28 December 2011 (UTC)
 * Never mind, I found it. Thanks, Marasama (talk) 18:12, 4 May 2012 (UTC)

Why does a reference link to another Wikipedia article?
I don't think this is allowed... I didn't want to delete the reference, so I'm posting this. Bladeor (talk) 20:04, 31 March 2014 (UTC)

Classification
The template at the bottom of the page, in the "Visible nebula" row, doesn't list "dark nebula" among the types (within the parentheses ) of "Diffuse nebula", but the article states that: Diffuse nebulae can be divided into emission nebulae, reflection nebulae and dark nebulae.

Moreover, in the Classical Types section you can read that Objects named nebulae belong to 4 major groups: H II regions, Planetary nebulae, Supernova remnant, Dark nebula ... but the other types listed in section 3 (Diffuse, Planetary and Supernova remnants) are somewhat confusingly not consistent with the four groups cited above.

--Carlo89martini (talk) 19:51, 17 August 2020 (UTC)
 * The classification of nebulae obviously needs some clarification. Ruslik_ Zero 09:13, 19 August 2020 (UTC)

Clarity required about the size of the Orion Nebula
While describing the size of the Orion Nebula, the author has compared it to the "diameter of a full Moon". I think this creates a lack of clarity in the reader's mind about what exactly does the author want to convey by the diameter of the "full moon" - the physical diameter of the moon or the angular diameter when seen from the earth via naked eye?

I think mentioning that we are talking about angular diameter here and adding a reference link to the wiki article will solve the problem and help eliminate the ambiguity of the phrase "diameter of full Moon". MartyMcFly88 (talk) 20:21, 17 December 2020 (UTC)
 * Clarified. Ruslik_ Zero 17:54, 18 December 2020 (UTC)

Astronomie
I love astronomie 2A01:E0A:A:A640:F862:DC3E:D2EE:7CD2 (talk) 20:10, 3 February 2022 (UTC)

Vacuums achievable in labs
The statement about molecular densities achieved in laboratories is incorrect. 10^-13 Torr are possible with modern chambers and pumping techniques. 10^4 molecules/cm^3 densities are possible.

Please edit

https://www.mks.com/n/principles-of-vacuum-technote#:~:text=The%2520lowest%2520pressure%2520that%2520can,14%2520%E2%80%93%252010%252D15%2520Torr.

Surface Scientist 2600:1011:B195:611E:A148:8470:8F42:D73E (talk) 17:04, 5 July 2024 (UTC)