Talk:Outer space

Cis-lunar space

First, I concur with the assessment of this article as B-class for Wikiproject Spaceflight. In reviewing the article though I noted that no particular mention is made of the region commonly called cis-lunar space even though that redirects here. (From a spaceflight perspective, cis-lunar space can be roughly defined as the region within which the gravitational influence on a spacecraft of the sun is dominated by the gravitational influences of the earth and moon, and thus the sun's influence can largely be ignored for most trajectory analysis purposes.) Another aspect of cis-lunar space: it is apparently "swept clean" of small objects by the moon's gravitation, i.e. there are not lots of little moonlets, whereas beyond cis-lunar space there do appear to be objects which closely share the earth's orbit around the sun. My impression is that these two factors make the region "special" enough to deserve mention in this article. YMMV, of course! (sdsds - talk) 04:33, 5 May 2012 (UTC)

Thanks Sdsds. Cis-lunar space is briefly mentioned in the Geospace section. Regards, RJH (talk) 16:19, 5 May 2012 (UTC)

A search for "cislunar" finds 6.1; it should find 6.1.1. And "cislunar" seems more common than "cis-lunar", so it should appear in the section at least once. 94.30.84.71 (talk) 11:13, 13 October 2012 (UTC)

What is it that a search finds or should find that is described by the numbers "6.1" and "6.1.1"? - Fartherred (talk) 09:45, 16 October 2012 (UTC)

GA Review

GA nom closed as fail by nom

This review is transcluded from Talk:Outer space/GA1. The edit link for this section can be used to add comments to the review. Reviewer: Titodutta (talk · contribs) 08:41, 10 May 2012 (UTC) Let's start I am starting review the article. Please feel free to join! --Tito Dutta ✉ 08:41, 10 May 2012 (UTC) First read I have read the article before starting review. I'll keep on adding notes and comments below. Hope for the best! --Tito Dutta ✉ 08:41, 10 May 2012 (UTC) First read comments First things to look for Basic problems Comment The article completely lacks reliable sources – see Wikipedia:Verifiability N No problem! There are cleanup banners that are obviously still valid, including {{cleanup}}, {{wikify}}, {{POV}} N No major problem! The article is or has been the subject of ongoing or recent, unresolved edit wars N No! The topic is treated in an obviously non-neutral way – see Wikipedia:Neutral point of view. N No problem First look assessment: Y Ok! There is not any "basic problem" in the article, and we can start the review in detail now. --Tito Dutta ✉ 08:41, 10 May 2012 (UTC) u20 ===Image=== Alignment All the images are aligned right mow. You can place 1–2 images at left side of the article! --Tito Dutta ✉ 08:41, 10 May 2012 (UTC) Per WP:IMAGES#Location, "Do not place images on the left at the start of any section or subsection". Only one of the images is not at the start of a section, so I shifted that to the left. Regards, RJH (talk) 15:30, 10 May 2012 (UTC) File:Convert ru kosmos080.jpg a) Is it a stamp? According to file description: Envelope Moscow Yuri Gagarin SG "The anniversary of the first manned space flight" Moscow 1962 (translated using Google Translator). If it is a commemorative stamp/post card, why don't you mention it in the caption? b) Also since this is a painting, you can think of replace the image with this original image: File:Gagarin in Sweden.jpg (not applicable if you are going to follow "a"). --Tito Dutta ✉ 08:41, 10 May 2012 (UTC) I modified the caption. Regards, RJH (talk) 15:30, 10 May 2012 (UTC) Image size Some images are distracting, I feel, because of image size. This one File:Magedurger Halbkugeln Luftpumpe Deutsches Museum.jpg etc. This size of this image File:Aurora-SpaceShuttle-EO.jpg is 300px currently. As far I can understand, all the images in the article are very important, so, why are you using 300px for this image only? I have noticed in most of the images you have used the images as thumbnail, if possible bring the image sizes to match with quote boxes (add 175px or 200px). To do this: Go to edit mode Change the code like this [[File:example.svg|right|thumb|this is a caption]] >> [[File:example.svg|right|thumb|175px|this is a caption]] I know you know how to this, but GA reviewers are instructed to suggest in details. Hope it is alright for you--Tito Dutta ✉ 16:01, 10 May 2012 (UTC) Mmm, my understanding is that we generally want images to be thumbnails so that viewers can control the size. (WP:IMAGES#Image preferences and see also WP:IDD.) I've seen people express strong views about that in the past, so I usually only set the size in specific cases (such as the infobox). Regards, RJH (talk) 16:04, 10 May 2012 (UTC) Thank you. Did you have any further concerns? Regards, RJH (talk) 16:19, 23 May 2012 (UTC) Closing GA nom. RJH (talk) 17:39, 30 May 2012 (UTC) I apologize, I did not notice May 23rd's post (missed it in watchlist most probably– sometimes a talk page message is helpful, anyway..), what is the reason of withdrawing the nomination? Will add a talkback template in your template (I do not use tb template, so will write manually) --Tito Dutta ✉ 18:35, 30 May 2012 (UTC) There was no response or activity, so I decided to close the GA nom rather than leave it bottlenecked. I may try again later, or somebody else can try to take it through. Regards, RJH (talk) 00:54, 31 May 2012 (UTC) This is unfortunate! I request you to undo the withdraw! Sometimes, see here, for last 20-25 days I am continuously requesting editors to join the review, but no one is joining: Talk:Islam/GA1#Comments, I have contacted nominator in his talk page multiple times too. No response. And sometimes nominator closes reviews since there is not any response. On one hand I apologize for delay here, on the other hand, you could post a message in my talk page before closing the review. I strongly request you to undo the withdraw! --Tito Dutta ✉ 08:19, 31 May 2012 (UTC) No thank you. I'll let you focus on your other reviews. Regards, RJH (talk) 14:39, 31 May 2012 (UTC) I am trying to find what should be done now (to re-start the review etc)! --Tito Dutta ✉ 16:12, 31 May 2012 (UTC)

Revision of images

I reverted a wholesale re-arrangement of the images in this article, but I thought I should state on this page the reasons why. Firstly, the current arrangement and selection of images was intended to complement the neighboring text and provide additional insight, per WP:PERTINENCE. The newly added pictures didn't seem to add much of anything besides some vaguely associated imagery. They also displaced the prior images from the location where they were most relevant, while creating a gallery. However, this gallery didn't add the kind of informational value that is appropriate per WP:Galleries. The value of the existing images was already present in the previous arrangement; there was a loss of association by placing them in a gallery. Finally, several of the images were given fixed dimensions, which prevents readers from selecting their preferred image size.

If the current selection and arrangement of images is deemed unacceptable, please discuss. Thank you. Regards, RJH (talk) 23:40, 12 May 2012 (UTC)

No need to explain yourself, I was here to update articles effected by the missing bow shock. Good luck with the review! Fotaun (talk) 19:02, 14 May 2012 (UTC)

Thanks. Regards, RJH (talk) 19:41, 14 May 2012 (UTC)

Religious views on Space

I can't find any Wikipedia coverage on religious views on space, nor in this article. Nevertheless, I am aware of some religions have explicit objection to man's involvement in space. Does anyone know where this might be covered in Wikipedia? If not, should we not include a brief section in this article? — Preceding unsigned comment added by 24.106.205.232 (talk) 14:46, 17 June 2012 (UTC)

There's Religion in space, but that article is more about religious practices during spaceflight. I'm not aware of any particular objections of the type you mention, but perhaps you can provide some WP:RELIABLE citations to back up your perspective? WP:WEIGHT would apply to this proposal. Regards, RJH (talk) 20:04, 17 June 2012 (UTC)

Edge/boundry of a galaxy?

The article discusses the boundary between the earth's atmosphere and intrastellar space, and between intrastellar space and interstellar/intragalactic space, but not between intragalactic space and intergalactic space. In other words, are there equivalents to the heliosphere (termination shock, heliosheath, and heliopause) surrounding galaxies?

Phantom in ca (talk) 08:57, 24 June 2012 (UTC)

Not clearly defined ones, as far as we know. —Alex (ASHill | talk | contribs) 09:13, 24 June 2012 (UTC)

Gravity defines a galaxy. In a galaxy, matter (stars, plasma, etc.) is gravitationally bound to the galaxy. In true intergalactic space, matter doesn't orbit the center of mass of any single galaxy. In this way, one can at least define the region where the galaxy "clears the neighborhood". But, galaxies have galactic halos, and large galaxies often have satellite galaxies, so a simple sphere of gravitational influence is not enough for a definition that captures the diversity of structures of galaxies. Lenticular, spiral, elliptical and dwarf galaxies have essentially different features; the area above the disk of a spiral galaxy, for example, is well within the gravitational sphere of influence, and has the same distance to the center as in a similarly-sized elliptical galaxy, but doesn't contain stars. Also, galaxies are not solid objects but may be disturbed by other galaxies, so this definition doesn't cover all cases. Perhaps a better view is to consider the fact that galaxies are essentially concentrations of dark matter, which is apparently incapable of gravitational collapse above a certain density. It would make no sense to attempt to define an "edge" for such a diffuse object. Dark matter haloes, if they exist, are much, much larger than the optically bright center of the galaxy. Practically, however, one can always set an arbitrary (but practically useful) brightness or density limit and measure the size thus defined. --vuo (talk) 10:09, 24 June 2012 (UTC)

There are other astronomical objects that don't have a precise boundary either. Examples include globular clusters, open clusters, and molecular clouds. In these cases other means are used to describe their size, such as the half-mass radius for a globular cluster. Regards, RJH (talk) 18:07, 24 June 2012 (UTC)

A closely related question. Was trying to find information on intergalactic space but was redirected here - Outer_space#Intergalactic which seems pretty inadequate especially compared to the article on the interstellar medium - Interstellar_medium! Anyway my question was about the basic density or range of densities of intergalactic space, mainly so I can compare it to interstellar and solar system space densities. Lucien86 (talk) 04:57, 24 August 2012 (UTC)

Yes I agree that we could use a well-developed article on the intergalactic space. There is Warm–hot intergalactic medium, which is also pretty sparse. Regards, RJH (talk) 05:33, 24 August 2012 (UTC)

Location categories

I think we should have categories for events, objects, etc. located off planet. categories for near earth orbit, or geostationary orbit, for objects on the moon, on mars. not a lot yet, but since we can categorize earth bound events and objects by their location, why not such off planet?Mercurywoodrose (talk) 05:01, 26 November 2012 (UTC)

Callisto picture

That's a nice picture of Callisto. But what is it doing on this page? I CTRL-F'd for Callisto material in the article and found no mention of it. So why the picture? Leitmotiv (talk) 08:23, 6 January 2013 (UTC)

Tue. I think a picture of a space probe would be more appropriate. Serendi^podous 10:30, 6 January 2013 (UTC)

That or a satellite. Leitmotiv (talk) 00:03, 7 January 2013 (UTC)

"Achieving orbit requires a minimum velocity of 28,400 km/h (17,600 mph)"

An orbit can be arbitrarily slow if one travels arbitrarily far from Earth; and one can travel arbitrarily far from Earth by moving vertically with an arbitrary velocity.

I suspect this statement is a misunderstanding of some other statement (probably about low orbits). — Preceding unsigned comment added by 131.111.248.243 (talk) 17:41, 25 January 2013 (UTC)

I think you're confusing linear velocity with angular velocity. A spacecraft in a higher orbit has a lower angular velocity, but greater linear velocity; it takes longer to go around the Earth, but not because it is moving more slowly, but because it has further to travel as the circumference of its orbit is greater. --W. D. Graham 21:16, 25 January 2013 (UTC)

You also move more slowly going higher, see Orbital speed. --Cyclopia^talk 21:32, 25 January 2013 (UTC)

Yeah, I just calculated that and dropped a T, please ignore me. --W. D. Graham 21:35, 25 January 2013 (UTC)

It is somewhat counter-intuitive that lower orbits require speeds higher than the speeds required for higher orbits. The statement in the article that started this discussion is in some sense misleading: theoretically there are trajectories that lead to high orbits along which the speed never reaches the speed required for a low orbit. But what this sentence is trying to convey is still important: in almost every practical case a spacecraft attempting to achieve orbit is headed for a low orbit first, even if it is only a temporary "parking" orbit. We should nonetheless consider alternative wording.... (sdsds - talk) 23:46, 25 January 2013 (UTC)

The statement is about achieving orbit. In context, it's clear that the statement refers to achieving orbit from the ground. Properly, the number in the lede is directly from the main text of the article, where it is further explained and cited. —Alex (ASHill | talk | contribs) 11:21, 26 January 2013 (UTC)

Achieving orbit 'from the ground' is not a condition which makes the statement true. As it currently stands, the statement completely misleading; it's just plain false, and whatever it does mean is not explained. If one wishes to orbit the Earth, it is simply not necessary to go at that large speed. You can reach an arbitrary height above Earth with an arbitrarily small speed; and orbits can have an arbitrarily slow velocity (yes, velocity - not just angular velocity) by orbiting from a further distance [v = sqrt(GM/d)]. The article does not indicate any conditions about the height of the orbit or anything else which would render it valid. I'm removing it for now; please don't replace it without adequately rewriting it. --131.111.248.243 (talk) 00:31, 29 January 2013 (UTC)

Please reread my comment, and read the section "Space versus orbit", from which this (appropriately, in my opinion) shorthand phrase in the lead is taken. What in the statement is inconsistent with the cited source? Again, in context, it's clear to me that the statement refers to the spacecraft that have achieved orbit, all of which are low Earth orbit. If you want to change the phrase in the lead to "low Earth orbit", OK, but I think that that is worse because it requires more explanation. —Alex (ASHill | talk | contribs) 02:35, 29 January 2013 (UTC)

I have read your comment. The reference that supports the main text number refers to "Just what does it require to get into Low Earth Orbit?" which is what the main text refers to. The statement in the lead makes unqualified reference to achieving orbit. This makes it false and unsupported by the cited source. - Fartherred (talk) 03:50, 29 January 2013 (UTC)

The speeds referred to in the cited source are 7814 meters/sec and 8KPS. That is 28,130 kilometers/hour and 28,800 kilometers/hour. Rounding first figure to the nearest two significant figures gives 7800 meters/sec which I put into the text. - Fartherred (talk) 05:59, 29 January 2013 (UTC)

The "space versus orbit" section does not actually address the difference between space and orbit and it gives no clear explanation of how the speed of an orbit may decrease as one goes farther into space. — Preceding unsigned comment added by 131.111.248.243 (talk) 18:10, 29 January 2013 (UTC)

GA: Should we try again?

When I visited this article and saw the size, source length and how it was written I immediately believed that it was a GA or A Class. I was surprised to find that it had failed a GA. Looking over the reasons that the GA had failed nothing was actually noted as being wrong with the article. Something tells me that this article could probably be taken in for another GA and pass. Should we have another go at putting this in? MIVP (I Can Help? ◕‿◕) - ^{(Chocolate Cakes)} 08:52, 21 May 2013 (UTC)

Stating theories as fact

As the editor at 15.211.201.82 noted[1] the phrase "Observations now prove that it also contains dark matter and dark energy" is an "Extraordinarily claim despite unsettled science". Sources say "implying" and "evidence for" and "Theorists still don't know what the correct explanation is"... so far from "proven". And even citing "overwhelming consensus of astronomers" being (some percentage) sure about the existence of something does not add up to "100% sure" or "proven" or "are the dominant components of space" per WP:SYNTH. Also the linked articles dark matter and dark energy state "hypothesized" and "hypothetical" so that would have to be resolved (i.e. take it up on those talk pages if this has been "proven"). Fountains of Bryn Mawr (talk) 19:39, 31 May 2013 (UTC)

The source I added says "It turns out that roughly 68% of the Universe is dark energy. Dark matter makes up about 27%." I don't think it's synthesis to turn 95% into "dominant"; that's just rewording into language appropriate for the lede of an article not directly about this topic. There's nothing equivocal about that, and there is in fact very little debate amongst astronomers and astrophysicists that dark matter and dark energy exists. Of course, we don't know what it is. However, "dark matter" and "dark energy" are just terms that parameterise our ignorance.

Dark matter simply means some kind of matter that interacts with other matter by gravitational forces but not electromagnetic or strong nuclear forces (weak nuclear forces are unclear, as far as I know). Galaxy rotation curves, the CMB power spectrum, gravitational lensing are some of the observations that require that something (or somethings) meeting that description exists; whatever it is, we call it dark matter. Any particular explanation of what dark matter is is indeed far from proven. Similarly, dark energy is the word we use to describe whatever it is that causes the fourth bump in the CMB power spectrum as well as the increase in Type Ia supernova redshift as a function of observed brightness.

Yes, there are all sorts of subtleties about what these are; these are best left for the articles on them specifically. In the lede of this article, all that merits mention is that these things or classes of things, whatever they are, exist. It is true that nothing is ever proven; however, it's unnecessarily cumbersome to equivocate on everything in the lede as the current version of the article does about dark matter and dark energy. We don't prevaricate about everything else in the lede, even though the statement that nothing is ever proven applies equally well to the statement that outer space is a hard vacuum with a little bit of hydrogen, magnetic fields, and neutrinos.

I've been meaning to clean up the other articles (where going into this level of detail is worthwhile); maybe this is my reminder to do so.

Now, the outer space article is a bit strained in how it treats what we think of as outer space. It's a vast topic, and I normally think of outer space as much closer to home than intergalactic or even intragalactic space; certainly, within the solar system, neither dark matter nor dark energy are dominant at all, and dark energy is irrelevant even within galaxy clusters. That's why I reworded the bit in the lede to say that it's on intergalactic scales that dark matter and dark energy are dominant. —Alex (ASHill | talk | contribs) 22:08, 31 May 2013 (UTC)