Talk:Extraterrestrial skies

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Contents 1 Name of article 2 Gas Giants 3 Name of article 4 Improving the article 5 Featured article is ours -- in a few months. 6 This should be added 7 Sylvia 8 size of the moon as it appears to be as seen from the earth 9 Apollo 15 Lunar Rover Camera attempt to observe eclipse. 10 Pluto 11 Way, way out... Magellanic clouds 12 Apparent Magnitudes 13 Sunrise as seen from Venus - incorrect? 14 Seeing stars from the Moon during the day 15 Grammatical error 16 Pluto 17 A note to the creator 18 Contradiction

[edit] Name of article

surely it should be called Skies of other planets? Deus Ex

Surely everything on this page is/ought-to-be covered on the individual planets' pages? Also, the Moon is not a planet. Jonel

I disagree. Paranoid 11:15, 5 Jul 2004 (UTC)

What colour can be the skies of other planets? Paranoid 11:15, 5 Jul 2004 (UTC)

Time, date and astronomy on Mars#The_color_of_the_sky -- Curps 12:21, 5 Jul 2004 (UTC)

[edit] Gas Giants

I think this is an interesting page that deserves more work. Does anyone have any knowledge of what the sky colour would be on the gas planets? The Singing Badger 18:20, 24 Sep 2004 (UTC)

It is hard to say. Because of the Rayleigh scattering, One would expect a blue sky. Add a little methane and one gets a cyan sky. The clouds vary from white to pink or yellow. (chemically stained). -- Ŭalabio 16:36, 2004 Dec 18 (UTC)

Since gas giants don't have surfaces, how can one see a "sky" at all from below the cloud tops? 70.168.32.250 06:08, 25 January 2006 (UTC)

[edit] Name of article

Over on Wikipedia:Featured article candidates, Alkivar suggests that since we include the perspective from moons, comets, asteroids, et cetera too, we should move the article to a more appropriate name. ¿Does anyone have any suggestions? I have some ideas, but I want to sleep on them.

--

Ŭalabio 11:02, 2004 Dec 18 (UTC)

I slept on it and have decided to run with my idea:

Extraterrestrial skies

If none object, I shall move the article tomorrow. On another note, If you follow the link at the top of the page, you can see what the objections are to this being a featured article and fix it.

--

Ŭalabio 16:36, 2004 Dec 18 (UTC)

I support this name change. The Singing Badger 17:28, 18 Dec 2004 (UTC)

Well now, it is the next day, and 100% of all respondents approve the move. I shall move the article now.

I moved the page, fixed the redirects, fixed the AddSectionCode, fixed moved the section on { { fac } }, et cetera. I probably missed something.

[edit] Improving the article

The following is a list of comments made on a discussion at Wikipedia:Featured article candidates by Alkivar (I removed some that are made redundant by changing the name of the article). I would like to work more on this article but (a) I'll be away for a few weeks and (b) I've reached the limits of my scientific knowledge. However I've added some comments to Alkivar's comments to aid futuire editors.

- Lead in WAAAY too brief Yup. Needs a discussion of what a 'sky' actually is, what factors affect its colour, and what kinds of things (moons, rings, stars) one might expect to see in the sky of a planet.

- Information on Mercury reads stilted and broken. I'll see if I can fix this.

- Information on Venus is 2 lines?!?!! Since Venus's sky is basically, erm, orange smog, there's only so much one can say!

- Mars section needs reformatting badly Yes, there are probably too many pictures which should be deleted and/or rearraned so they're not all in a line.

- Jupiter needs serious work as 90% of its content regards its moons. Material could be added on the varying cloud layers on JUpiter, perhaps?

Hope this helps, The Singing Badger 17:46, 18 Dec 2004 (UTC)

I added another paragraph to the introduction. Now it is merely too brief instead of way too brief. ;-) -- Ŭalabio 22:14, 2004 Dec 18 (UTC)

---

I have an idea about how we can solve the Venusian problem:

As The Singing Badger states, "Since Venus's sky is basically, erm, orange smog, there's only so much one can say!" It appears to me that Venus has three skies:

1. Just above the clouddeck -- we can take a screenbrage from Star Wars Episode V: The Empire Strikes Back and edit out Cloudcity.  ;-)
2. A point halfway between the bottom of the clouds and the surface showing the bottom of the clouddeck and the surface, as well as the horizon.
3. The surface view.

We could treat Titan the same way. Although Jovian planets lack a point 3, we can explain their points 1 and 2. We can explain that the clouds of Venus and the jovian planets might have bacteria in them and, as an historical note, point out that after the idea of bacterial life in the atmosphere of Jupiter arose, some people got carried away, and imagine giant improbable monsters living in the clouds. ¡We have not even begun to get into the skies of extrasolar worlds yet!

[edit] Featured article is ours -- in a few months.

---

I am very proud of all of you. I stumbled across this article in middecember. I could tell that this article is ready for featured article. Unfortunately, this time of year was just to hectic. We all put in as much time as we could trying to work out the last few snags, but, we just did not have the time.

I suggest that we meditate about how to improve the article such as explain the physics better and go over theoretical skies instead of just the ones in our solar system. After coming up with some ideas, we can get some help from peer review, in February. In March we can resubmit this to featured article candidates, where it will succeed this time.

Understandably, if any of you have any other ideas, I defer to you, because you people built this article into the fine state in which I found it. ¡You people are paragons of the wikiway! --

Ŭalabio 06:50, 2005 Jan 4 (UTC)

---

[edit] This should be added

Write more about the sky seen from Venus above the clouds, the appearance of Mercury and Venus from Mars, the sky seen from big asteroids as Ceres

Isn't this all somewhat theoretical and/or speculative, and not quite factual, describing findings or hard data, as an encyclopedia should do?

[edit] Sylvia

Why is the Sylvia section notable? I am all for it being here if it is notable enough, but why is it more notable than say planetoids like Ceres, Quouar, Ixion, etc.? It seems "fluffy" and unnecessary.

[edit] size of the moon as it appears to be as seen from the earth

I want to carry out a scientific experiment regarding the cosmic bodies in the space in order to broaden my knowledge on matters regarding the solar system as well as astronomy. Can you please provide me with the really size of the moon, it,s distance from the earth as well as the size it appears to be when seen from the earth in order to enable me to carry out this experiment / investigation.You can send me this data via my e-mail.

[edit] Apollo 15 Lunar Rover Camera attempt to observe eclipse.

Checked with the Apollo Lunar Surface Journal and retrieved the information. The eclipse took place on 6 August 1971. Goto [1] for details. Note the capcom - crew discussion at 262:16:48 hours mission elapse time. Panamango 04:58, 23 August 2006 (UTC)Gary Fearon

[edit] Pluto

As Pluto is no longer considered a planet, shouldn't that be added to it's section on this article? --KCMODevin 16:54, 29 September 2006 (UTC)

[edit] Way, way out... Magellanic clouds

I posted a question on Talk:Magellanic Clouds about where would be appropriate for a description of the sky on a planet in the Magellanic clouds. How would our galaxy appear? GBC 18:01, 6 December 2006 (UTC)

[edit] Apparent Magnitudes

How do we know things like the apparent magnitude of Earth from Venus? For that figure, assuming the article means maximum brightness, the magnitude that I calculated differed from the given one by .5. Many other apparent magnitudes from non-Earth skies are also given. My point is, either these magnitudes have been measured, in which case a source should be cited, or they have been calculated, in which case the calculation should be made explicit or cited. If no one answers within a couple of days, I will mark those things as requiring citations. Kier07 18:48, 14 December 2006 (UTC)

I'm pretty sure thay've been calculated by someone rather than measured; some footnote from whoever calculated them would be good, I agree. Deuar 10:43, 15 December 2006 (UTC)

I agree. The thing is, this calculation depends on certain data. For instance, I haven't seen any confirmed, reliable data on the apparent magnitude of a full Earth as seen on the moon. One possibly accurate web site (debunking the notion that the moon-landing was a hoax) said that a full earth is 68.4 times brighter than a full moon, making it magnitude -17.33 at the brightest. I've also seen "at least 50 times brighter." When I consider the albedo of the Earth and Moon, and the difference in their sizes, I calculate that a full Earth should only be 41 times brighter than a full Moon. If we knew the brightness of the Earth on the Moon, we could do it at any distance, e.g. from Venus. The same is true of the other magnitudes as well... the calculation is simple once we have a little bit of information at hand. It's important to see where we get this information; maybe it's available in some kind of astronomical reference book. Anyway, I've marked these parts in the article with "citation needed"; hopefully someone will be able to find that information. Otherwise, I think it wise for me to delete those claims in a week or so until some substantiation can be found. Kier07 14:00, 18 December 2006 (UTC)

That, or round them off to the nearest sensible magnitude and indicate that they are approximate. Regarding e.g. the moon, the calculation becomes more tricky the more accurate you want to be. For example albedo tends to depend on the solar phase angle, and spikes upward when airless bodies are viewed with the Sun directly behind you − the "opposition effect" which makes the full moon so markedly brighter than an "almost full" gibbous moon. Deuar 16:18, 18 December 2006 (UTC)

[edit] Sunrise as seen from Venus - incorrect?

If the Sun could be seen from Venus' surface, it would appear to rise and set in a 243 day cycle

This is incorrect. Venus has a retrograde rotation, which causes the rotation to "catch up" with the Sun. The period between one sunrise and the next on Venus is about 120 Earth days. I don't know the exact period as I don't remember the formula for calculating it for retrograde planets. --B.d.mills 09:49, 1 April 2007 (UTC)

[edit] Seeing stars from the Moon during the day

It should be possible to see the brightest stars and planets from the surface of the moon when the Sun is visible. The trick is knowing where to look. Under favourable conditions, the brightest stars can be seen from the surface of the Earth during the daytime with the naked eye. Venus is particularly easy to see during the day if one knows where to look and the viewing conditions are favourable. There should not be great impediment to seeing the brightest stars and planets from the surface of the moon. --B.d.mills 10:03, 1 April 2007 (UTC)

From the moon, yes. But Earth? Never heard of that and it sounds wrong. IvoShandor 19:02, 1 April 2007 (UTC)

Despite the date, it is not an April Fools' hoax. Under favourable conditions, I have seen Venus, Jupiter and Sirius with the Sun above the horizon. At this time of the year, Sirius can be observed just before dusk. The trick is knowing where to look. To facilitate this, go outside shortly after dusk and wait until Sirius is visible. Line it up with a prominent object such as a power pole or tree and mark your position carefully on the ground. Note the time. Then go outside 7 days later, but 28 minutes earlier in the day. Stand in the position you marked, and Sirius should be visible in the same place but with the Sun above the horizon. It's tricky to see because one must look in exactly the right place, but once you do find it, it is not hard to see.

It is easier to view bright stars or planets in the daytime in the morning, because one can get up before sunrise and then simply follow the bright planet or star in the sky as the sun rises.

References: http://www.abc.net.au/science/k2/homework/s95616.htm

--B.d.mills 03:58, 2 April 2007 (UTC)

Do you think a casual observer on the moon (daytime) would notice any stars or planets? That is, if they weren't specifically looking for them, just walking around? Sometimes I wonder how people do this.. I can barely see 2nd magnitude myself, in the middle of the night. Sagittarian Milky Way 21:05, 2 April 2007 (UTC)

[edit] Grammatical error

Under the title "Extrasolar Planets," there is a sentence which begins with the words, "An hypothetical." The usage of "an" with regard to words beginning with an "h" is considered pedantic (H.W. Fowler, 1926). This concept is derived from the British "Cockney accent" where speakers don't pronounce the "h", beginning the word with the vowel sound instead. I have corrected it, guvnah. 72.92.22.124 06:52, 28 May 2007 (UTC)

[edit] Pluto

The Pluto section should be updated. I still think it's informative, and so shouldn't simply be removed. But Pluto's demotion to mere space-junk should be worked in.72.92.22.124 06:55, 28 May 2007 (UTC)

[edit] A note to the creator

Um, I know this isn't exactly helping the betterment of this article, but whoever came up with the idea is a flipping genius. Thank you, whoever it is. You made planetary astronomy not just interesting but fascinating. This happens to be an interest of mine and I am always disappointed that most of the written sources on the subject are full of boring academic dribble and fail to capture just how fascinating our solar system is for the average Joe. Little articles like this help a lot. They make it real. -- §HurricaneERICarchive 08:20, 22 December 2007 (UTC)

Yes, I completly agree, this is was a great idea to create such an article. Thank you all!--FrancescoA (talk) 19:33, 25 December 2007 (UTC) Still some questions:

• The Sun is a G2 yellow dwarf. The light visible on the moon is not filtered by atmosphere. Why seem the sun appear white and not a (bit) yellowish?
• What would be the apparent luminousity of the full earth? full moon is about -12,7^m The earth is about 3,5 times larger than the moon, this ^2 would be ~ 12, larger albedo, so say 20 bis 30 times brighter. Ah I remember the difference seen from mercury -5,2 and -1,2, so the earth should be about -16,7^m. Very bright indeed. One should easily read the newspaper, isn't it?
• What would be the "brightness" of the new earth (only shine by full moon)? I estimate 0 to -2^m. Am I far away?
• Mars would appear from Phobos 2,500 * brighter than the full moon. Wow. This means about over the middle of full moon and sun, about -21^m? —Preceding unsigned comment added by FrancescoA (talk • contribs) 20:02, 25 December 2007 (UTC)
• How bright would Phobos appear from the mars? —Preceding unsigned comment added by FrancescoA (talk • contribs) 19:57, 25 December 2007 (UTC)

[edit] Contradiction

There might be a contradiction on the apparent diameter of parent planets from their moons. Someone claims that:

"Metis, the innermost moon, would see Jupiter's apparent diameter bloated to a stupefying 68° (130 times the visible diameter of our Moon, covering 18% of Metis' sky); no other known moon of the solar system enjoys a more awe-inspiring spectacle."

Yet earlier in the article, during Mars:

"From Phobos, Mars appears 6,400 times larger and 2,500 times brighter than the full Moon as seen from Earth, taking up a quarter of the width of a celestial hemisphere."

Does this mean that Mars would cover 25% of Phobos' sky, or am i just being thick? Thisnamestaken (talk) 17:39, 8 February 2008 (UTC)

No, it doesn't mean Mars would cover 25% of Phobos's sky. The "quarter of the width of a celestial hemisphere" refers to angular diameter, specifically one of 45°, which of course is less than the 68° for Jupiter from Metis. Transformed to area, Mars would "only" cover about 7.6% of Phobos's sky. 85.8.12.78 (talk) 22:23, 31 March 2008 (UTC)

I was confused by exactly the same thing. Perhaps it should be reworded. 90.212.120.95 (talk) 19:36, 27 April 2008 (UTC)