Talk:Formation and evolution of the Solar System/Archive 3

Archive 1

Archive 2

Archive 3

White Dwarf

White dwarfs shine by leftover heat and can take up to 10 trillion years to cool off.[1] -- Kheider (talk) 18:20, 10 June 2008 (UTC)

That is 10,000 billion years. The statement actually says trillions meaning at least 2000 billion years, more than 100 times the length of the universe to date, though the reality is that many billions could also describe 2000 billion or 10,000 billion, which seems more meaningful to me than "trillions". Thanks, SqueakBox 18:34, 10 June 2008 (UTC)

I think I prefer trillions since the Dyson reference (2) says "Detachment of planets from stars like the earth-sun system is considerably shorter than 10^15 years (=Quadrillion)." 10^9 = Billion and 10^12 = Trillions. Many of anything could be as few as 20 or 50, and I think using billions instead of trillions gives the wrong Order of magnitude. -- Kheider (talk) 19:51, 10 June 2008 (UTC)

One thing I was concerned about was ambiguity of the word trillion: it can mean 10¹² or 10¹⁸, though the second is becoming more rare. Same problem for billion. Maybe there is another way to word this in the article? CosineKitty (talk) 21:26, 10 June 2008 (UTC)

Are those usages still commonly used anywhere? I think the English-speaking world has pretty much standardized on billion=$10^{9}$ and trillion=$10^{12}$, but that could be my American bias. See long and short scales and MOS:NUM. ("Billion is understood as $10^{9}$ (short scale).")

I agree with Kheider's reasoning that trillion more accurately reflects the reference here (even though pretending we know anything about what will happen in trillions of years is iffy). ASHill (talk | contribs) 05:39, 11 June 2008 (UTC)

"Evolution"

I strongly discourage usage of the word Evolution in this context.. give me a argument for the usage in this particular case... Bambinn (talk) 18:32, 10 June 2008 (UTC)

What else would you suggest as an alternative. Thanks, SqueakBox 18:34, 10 June 2008 (UTC)

i think "development" or "process" would be a more appropriate word,.. Bambinn (talk) 19:42, 10 June 2008 (UTC)

"process of the Solar System" makes no sense. "Development" carries connotations of birth and growth but doesn't really cover ageing and death. "Evolution" is a commonly used word in these contexts, and Wikipedia already has a number of astronomical articles which employ it (stellar evolution, galaxy formation and evolution etc) Serendi^podous 19:47, 10 June 2008 (UTC)

(after ce) Bambin, Mierda del toro. From OED: III. The process of development.

Serendipodous is correct. •Jim62sch•^dissera! 19:51, 10 June 2008 (UTC)

If you look in the archive of this discussion page when this was the Featured Article, there was a lot of discussion about avoiding the word evolution. The only argument against it is that is it will make some people freak out because they think it means the same thing as Darwinism. The word evolution was in the English language long before the theory of natural selection came on the scene. And it does not mean the same thing as development: the former is a more neutral term that means gradual change over time. I still think we should leave it as is. CosineKitty (talk) 21:22, 10 June 2008 (UTC)

I've added a wiktionary link on the word. The link is awkward and not entirely appropriate, but the first definition of the word in wiktionary clearly applies to the use in this article. ASHill (talk | contribs) 01:10, 12 June 2008 (UTC)

Fate of Earth as sun's luminosity increases

This article makes it seem like it's a foregone conclusion that the Earth will become uninhabitable well before the red giant phase commences. That may well be if interference by intelligent life is not considered, but then I think it would be foolish to disregard the possibility that there may be some distant progeny of mankind alive at the time who would take interest in the continued survival of Earth as a habitat for life. Now, it's sufficiently remote that even an advanced civilization could thwart the swallowing of Earth as the Sun becomes a red giant, and it's impossible that anyone could thwart the eventual heat death to which all stellar systems eventually evolve, but it wouldn't be that difficult for an advanced civilization to deflect or absorb a percentage of the incoming solar radiation before it reaches Earth. In fact, even at a near future level of technological development, I don't see any reason why Earth could not be preserved until the onset of the red giant phase. Now, I'm not suggesting that we clutter the article with WP:OR far-future Earth saving strategies, but might it be possible to include a caveat stating that the studied model of Earth's fate doesn't include the role of life? One would think that might be a significant omission considering that life has already shaped this planet's destiny as far back as the Oxygen Catastrophe. deranged bulbasaur 14:08, 11 June 2008 (UTC)

Even if humanity kills itself through stupidity, the extreme timescales we're talking about here mean that it's entirely possible that the Earth could produce another intelligent species in time to save itself from this easily averted apocalypse. Considering what else life has managed in less that 500 million years, it wouldn't even have to be a naked ape repeat. In that span, cephalopods might even get their shot at it. deranged bulbasaur 14:24, 11 June 2008 (UTC)

It's hard to imagine any changes to the Earth's atmosphere that could lengthen the time the planet could support life. (Perhaps considerably more dust in the atmosphere to reduce the impact of the more luminous Sun? Even so, the dust would absorb solar energy, presumably heating the atmosphere.) Certainly, the impacts of life could accelerate the evaporation of water. We'd certainly need a very credible reference, because this sounds like science fiction speculation that doesn't belong in this article, even if it is technically feasible.

I've reworded the paragraph slightly to make it clear that the source's definition of the habitable zone is surface temperatures that allow the presence of liquid water, which makes this paragraph more clear. ASHill (talk | contribs) 00:54, 12 June 2008 (UTC)

Most kinds of fine particulates have a much higher albedo than the surface of the earth. They'd doubtless absorb some energy, but they'd reflect a greater proportion. I'm not sure what you mean by "science fiction speculation" given that I haven't proposed adding anything about any particular method of remediation to the article, only noting that this scenario assumes utter passivity on the part of any intelligences then present. How is it speculation to simply note the range of possibilities considered in a prediction? I'll go ahead and make the change I've proposed and justified at length if nobody makes a credible objection. deranged bulbasaur 05:53, 16 June 2008 (UTC)

I've noted some concerns, but I'd say go ahead and make the change; it's easier to talk about real text than in the abstract. However, it is implicit that all comments about the future are predictions based on facts as we know them today; we can't and shouldn't mention every caveat. ASHill (talk | contribs) 13:07, 16 June 2008 (UTC)

I would think that the majority of readers will implicitly assume that the article refers to the case where intelligent life plays no role in the evolution of the system. The article is based on current scientific knowledge. It seems obvious that we have little idea of what life will be like and what it will be capable of in a few billion years, so it seems unnecessary to point this out in the article. There's no point in making a note of every possibility. AstroMark (talk) 19:22, 16 June 2008 (UTC)

I went ahead and made the change. Given the extremely minor alteration of wording necessary for it, I can hardly see that we're cluttering the article with unlikely caveats. deranged bulbasaur 23:34, 17 June 2008 (UTC)

That change is fine by me, more evidence that it's best to be bold first and then revert if someone objects; I think the discussion made it seem like a more substantial change than it really is. Talking about the impacts of intelligent life over the next 100 million+ years sets of my fringe and science fiction alarm bells, justified or not.... ASHill (talk | contribs) 00:04, 18 June 2008 (UTC)

We're all gonna die

I dunno if you watch Horizon, but every other week they always try to make out that the end of the world is coming in some form or another; they coined the terms "supervolcano" and "megatsunami". They also like using "Predator" theme music. Here they're claiming that the Milky Way/Andromeda collision is going to hurl the Solar System straight into Sgr A*. I haven't been able to find any information that backs up that assertion, though. Serendi^podous 09:04, 16 June 2008 (UTC)

Here's a piece by John Dubinski, who is featured in that Horizon piece. Not sure whether to include it or not. Serendi^podous 08:16, 17 June 2008 (UTC)

I would not include it. Yes, an interaction can scatter objects like the Solar System in random directions, but I don't think there's much reason for the Solar System to be more likely to be scattered towards the center of the Galaxy than in any other direction, and Sgr A* is a tiny target; the probability that we'd hit it is essentially zero. As the Galactic evolution of this (Wikipedia) article makes clear, the impact of the Andromeda-Milky Way collision on the Solar System will almost certainly be negligible. N-body simulations like the ones that Dubinski does (although I'm not familiar with his work) don't come close to predicting the motions of individual stars in the Milky Way or Andromeda; they can only forecast trends in the population.

On this side of the pond, I've never seen Horizon, but I'm inclined to think it's not a reliable source for a detail like this without a supporting written article. ASHill (talk | contribs) 23:58, 17 June 2008 (UTC)

The Horizon programme only mentioned the Solar System being flung into Sgr A* as a possibility. I don't think that the Horizon programme or the Dubinski article talk about anything that isn't already mentioned in this article. AstroMark (talk) 19:02, 18 June 2008 (UTC)

The Sun becomes a Red Giant in 5.43 billion years.

The Sun is 4.57 billion years old and will spend 10 billion years as a Main Sequence Star before it becomes a Red Giant. Is it okay to change 5 billion years to a more accurate 5.43 billion years? Thank You.Maldek (talk) 04:44, 20 June 2008 (UTC)

As long as it's properly sourced. Serendi^podous 05:08, 20 June 2008 (UTC)

No, it's not OK. The 10 billion years number is not certain at that level, and if it is, I doubt the number is exactly 10.00 billion years. We should not add inaccurate precision; best just to leave approximate numbers. ASHill (talk | contribs) 13:35, 20 June 2008 (UTC)

I agree with Ashill — everything I have ever read about the Sun's lifetime makes it clear that the 10 billion year figure is an estimate based on observations of other similar stars. The dynamic processes of hydrogen fusion in a complex object like a star are not understood that precisely. CosineKitty (talk) 14:13, 20 June 2008 (UTC)

Well, if he could source it, what's wrong with the number? 4.57 billion is within the level of precision of a lot of geological events. That it adds to 10.00 is just coincidence. Of course, this all presupposes reliable sourcing.OrangeMarlin ^{Talk• Contributions} 16:00, 20 June 2008 (UTC)

I think the claim is not based on sourcing, but based on subtracting $10-4.57$ and not properly following significant figure rules. ASHill (talk | contribs) 16:13, 20 June 2008 (UTC)

Earth's Moon

I think Earth' moon tidally lock in 50 billion years is obvious error. By this time, the sun will have fade into a black dwarf star, and also, Earth will have been thrown off by sun probably no later than 6 billion years, becasue whats call tidal interaction, even if sun lose 38% of mass they say now Earth still don't get to escape inceneration. Actually in about 4.3 billion years Earth's ocean and air would have been gone.--Freewayguy ^{Msg USC} 01:36, 26 June 2008 (UTC)

Hi Freewayguy. I agree with you. But where did you see that in the article? I looked and could not find anything like that. Cheers, CosineKitty (talk) 01:57, 26 June 2008 (UTC)

On Futuro subsection Moon-ring system, they origianlly said in 50 billion years; I change it to 200 million years.--Freewayguy ^{Msg USC} 04:01, 26 June 2008 (UTC)

Do you have a source for ~200 million years figure? -- Kheider (talk) 05:42, 26 June 2008 (UTC)

The 50 billion year figure is commonly accepted by astronomers. The figure is also cited in the article, so please don't change cited numbers. We don't know for certain what will happen to the Earth when the Sun goes red giant. Serendi^podous 06:28, 26 June 2008 (UTC)

What I meant when I said "I agree" was that it is confusing to say something will happen in 50 billion years when other parts of the article make it sound likely that the Earth and Moon won't even be here any more. Would it be reasonable to add some qualifying language to the 50 billion year figure? CosineKitty (talk) 10:13, 26 June 2008 (UTC)

Yes. I'll do that. Serendi^podous 10:28, 26 June 2008 (UTC)

I took a shot at rewording this part by splitting up the sentence and being more specific about what would likely cause destruction of the Earth/Moon system. Maybe an internal link from "Sun's expansion" to the relevant section would be a good idea too. CosineKitty (talk) 11:38, 26 June 2008 (UTC)

What about Venus then? We have little consensus say Venus will survive over sun's white dwarf, so if it still exists at that time its orbit will be 1.35 AU. Only because of tidal interaction say Earth will be swallow no matter what, actually we have no idea how big sun will be when its a giant star. Can vary any between 1 and 1.5 AU. Mars might still exist but not certainly so. Few consensus say Mars can still be envelop.--Freewayguy ^{Msg USC} 23:05, 26 June 2008 (UTC)

I'm confused. How are Venus and Mars related to the tidal locking of the Earth and Moon? Certainly, models disagree on the ultimate fate of Venus, Earth, and Mars, but I think the article accurately reflects the current state of confusion. ASHill (talk | contribs) 23:28, 26 June 2008 (UTC)

References: Schroder2008 and sun_future -- Kheider (talk) 00:45, 27 June 2008 (UTC)

Solar system's fate

What you mean as summary by mars and gas giant may be rip by white dwarf star? I thoguht Venus and Earth may or may not survive over sun's giant star stage. I thought Venus has slightly less than to survive than Earth. mars is likely to survive, but not positively.--Freewayguy ^{Msg USC} 03:37, 27 June 2008 (UTC)

Sorry it took me a little time to check sources with Google. See On the Final Destiny of the Earth and the Solar System (Rybicki & Denis 2001). It does appear as if the popular view is that Mercury is almost certainly a goner unless some other process alters its orbit. Venus is "most likely" to be destroyed. Earth is likely to be destroyed, but is more of a coin flip given the limited knowledge we have. So if the Sun engulfs Mercury, Venus, and Earth, Mars will likely be the closest planet to the (white dwarf) Sun. Then over trillions of years passing stars will slowly strip the gas giant planets from the weakened Sun. So perhaps Mars will be the last planet standing. But obviously this is not definitive. -- Kheider (talk) 05:47, 27 June 2008 (UTC)

Long-term stablilty section

Someone came and add a new page of Long-term stablity. This sub-section seems to exact imitates to Stability of the Solar System. Do this still needs to mention on this page or its no longer need.--Freewayguy ^{Call? Fish} 22:48, 14 July 2008 (UTC)

Can somebody please comment? Discussions always takes a loooong time.--Freewayguy ^{Call? Fish} 18:54, 15 July 2008 (UTC)

Please, explain what you mean, because I did not understand. Ruslik (talk) 19:04, 15 July 2008 (UTC)

Does this section even need to be mention on this page; because we cover this on Stability of the Solar Sytem.--Freewayguy ^{Call? Fish} 20:02, 15 July 2008 (UTC)

Formation and evolution is partially a summary style article, which means that long topics are covered more in depth elsewhere; hence the "Main article" hatnote in the long-term stability section. Thus, the long-term stability section ought to stay, and I think it's best left essentially as is.

Aside: is stability of the Solar System new? The article history dates back only to 2008 July 12; it's unclear where it merged from. ASHill (talk | contribs) 20:09, 15 July 2008 (UTC)

• Stablilty of our solar system; i guess should be merge with this page. It is part of evolution of solar system.--Freewayguy ^{Call? Fish} 00:20, 16 July 2008 (UTC)

Stability of the Solar System does appear to be a new article. I think it should be left as a separate article, assuming it can be expanded to discuss more details about chaos theory, computer simulations of the solar system, and other interesting topics in more detail than in Formation and evolution of the Solar System, which is already a fairly large article covering a huge scope. CosineKitty (talk) 01:31, 16 July 2008 (UTC)

• hi, i made Stability of the Solar System, using content from here. agree no merges necessary, props to you guys as it made the frontpage's 'do you know' . msg me for QsSpencerk (talk) 02:58, 18 July 2008 (UTC)

Continual reverts, warring, over inner planets fate

This user has gone through nombers of reverts and warrings in a violation of 3RR policy. This doesn't matter what the book states, first over white dwarf star we are not even completly sure if Mars will still exist yet. The source we have says foget about tidal interaction then Venus and Earth will escape to a higher orbit, and when sun becomes close to 1.11 AU; then Venus will become to 1.25 AU, and Earth up to 1.71 AU. The tidal interaction is only a study, just say because the Earth and Moon is in tidal drag with Sun will eventually make Earth get swept up by sun's outer layer. In other way to say Earth will probably be swallow up at this time. Second of all we don't exactly know how big the sun will be. The source I found earlier about Clues of death of our solar system say sun's expansion will be between 200 and 500 factors, any range between 1 and 1.75 AU. This leaves, only because Earth will probably not survive, then Venus might not survive. If the Earth survives over sun's RGB; then Venus will probably survive, and if sun's expanision gets clsoe to or pass Mars orbit; then Mars have chance to be engulf.--Freewayguy ^{Call? Fish} 18:16, 18 July 2008 (UTC)

Mars' eventualism greenhouse effect?

During this time it is possible that as Mars's surface temperature gradually rises, carbon dioxide and water currently frozen under the surface soil will be liberated into the atmosphere, creating a greenhouse effect which will heat up the planet until it achieves conditions parallel to those on Earth today, providing a potential future abode for life.

From discussion at desk, Mars have been losing it's atmosp from billions of years ago and mars don't even have an atmosp to make a greenhouse effect. When the sun starts to swell and solar ssytem to heat up, all of it's atmos will just drive off into space and instantly become like our Moon. Can someone fix this phrase or we should erase this whole phrase, becuse for MArs to be a blue planet again is unlikely. I wonder if these sources is even right.--SCFReeways 23:46, 8 October 2008 (UTC)

You'll need to provide some sources for that. Serendi^podous 08:02, 9 October 2008 (UTC)

• Does "possible" mean likely? Seems to me the phrase means Mars will likely be a blue planet. Does "Greenhouse effect" always mean thicker atmosp/ Mars have polar ice cap, and I believe is only the poles can make liquid ocean. For first billion year, Mars could still maintain it's atmosp, next billion years Mars could black out airless. The goal of encyclo is to make the information right, yes that's the point.--SCFReeways 18:02, 9 October 2008 (UTC)

  "Possible", without further context, should not be interpreted as "likely" or "unlikely" (which are themselves vague anyway). — Lomn 20:30, 9 October 2008 (UTC)

• Mars may be a blue planet by this time, by the atmosp will stay thin. Next billion-years Mars may black out and become just like Moon.--Freeway91 01:12, 10 October 2008 (UTC)

• What about "Greenhouse effect" Does Greenhuose effect always mean adding atmosp, becasue Mars atmosp will just get thinner to the solar wind, and Mars lack magnetic field. The source xite takes me slow load to view it.--Freeway91 22:17, 10 October 2008 (UTC)

NPOV Dispute

The purpose of wikipedia according to the NPOV articles is for the articles to maintain as close as NPOV as possible. "Evolution" is not NPOV as it endorses a biased hypothesis on how the universe was formed and is progressing and has not been concretely proven beyond a reasonable doubt. Even evolutionary biologist disagree on the origins and "evolution" of life and the universe. I am not suggesting to change the terms to Creationist (equally POV), but to put the terms into such terminology that would bring the article into NPOV rather than leave it in POV.--Coviepresb1647 (talk) 01:35, 15 November 2008 (UTC)

FYI, discussion regarding this should be centralized at Talk:Solar System#NPOV Dispute as they are related. --Ckatz^chat_spy 01:38, 15 November 2008 (UTC)

Removed tag added by confused? editor - was going to refer him to that discussion. Vsmith (talk) 03:02, 15 November 2008 (UTC)

50 billion

Is it a typo? In about 50 billion years, if the two worlds survive the Sun's expansion, they will become tidally locked to each other; each will be visible from only one hemisphere of the other.[75] 50 billion years or 5 billion? I guess after 50 billion years, the Milky Way Galaxy would have already merged with the Andromeda (if my memory is correct). —Preceding unsigned comment added by 144.214.5.22 (talk) 11:01, 21 April 2009 (UTC)

No it isn't a typo. Tidal locking is expected to occur between the Earth and the Moon in 50 billion years. The Sun will be a white dwarf by then, but the Solar System will still exist. The Andromeda/Milky Way collision is expected to occur at about the time the Sun begins to move off the main sequence in 5 billion years time. Serendi^podous 11:59, 21 April 2009 (UTC)

Chronology Piece

The time frame of the Solar System's formation has been determined using radiometric dating. How? Thanx. —Preceding unsigned comment added by 143.160.124.40 (talk) 21:18, 2 August 2009 (UTC)

This is not the appropriate place to explain how dating methods work, as it requires a very in-depth explanation that would overshadow and confuse the article at hand, nor is it directly related to the physical processes of formation. For that information, you should head over to Radiometric_dating

Forgot to sign Chardansearavitriol (talk) 00:22, 15 March 2011 (UTC)

Chardansearavitriol's note notwithstanding, a brief note would illustrate the dependence of current theory on certain kinds of dating. The main dating methods involve either a ratio of isotopes (like Potassium-Argon) or a ratio of ratios (like Uranium-Lead isochrons). Such a paragraph would be appropriate for several reasons. First, it would highlight the extremely high accuracy of some results (the Pb-Pb isochrons from meteorites) compared to others. Second, that accuracy bears on the great precision assigned to some early events.

The oldest meteorite measurement I am aware of is from Bouvier and Wadhwa's result published in Nature Geoscience; "... a calcium–aluminium-rich inclusion from the Northwest Africa 2364 CV3-group chondritic meteorite, which indicate that the inclusion formed 4,568.2 million years ago ... the oldest age obtained for any Solar System object so far". Typical errors for similar samples are, for example, "4,567.11 ± 0.16 Myr" and "4,568.5 ± 0.5 Myr". Think about the implications of such precision of that result for a moment. It permits special statistical inferences which underpin some of the modern models of formation. --203.89.168.149 (talk) 10:02, 10 July 2011 (UTC)

That article is apparently downloadable - I found a PDF at http://haroldconnolly.com/EES%20716%20Fall%2009%20Reading/ngeo941.pdf. --Sdoradus (talk) 10:06, 10 July 2011 (UTC)

The Sun's origin

I'd like to suggest adding something to the text about the mass and dimensions of the cluster in which the Sun was likely formed and about the effect upon the inner Oort cloud of a close encounter with another star during the first 100 Myr. (This was mentioned in a SciAm article this month, which also gave estimates for the cluster dimensions and distance of nearest approach.)

• Portegies Zwart, Simon F. (2009). "The Lost Siblings of the Sun". The Astrophysical Journal Letters. 696 (1): L13–L16. Bibcode:2009ApJ...696L..13P. doi:10.1088/0004-637X/696/1/L13. {{cite journal}}: |access-date= requires |url= (help); Unknown parameter |month= ignored (help)
• Kaib, Nathan A.; Quinn, Thomas (2008). "The formation of the Oort cloud in open cluster environments". Icarus. 197 (1): 221–238. Bibcode:2008Icar..197..221K. doi:10.1016/j.icarus.2008.03.020. {{cite journal}}: |access-date= requires |url= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

Thanks.—RJH (talk) 16:57, 23 October 2009 (UTC)

Added. Do you think more discussion of the Oort cloud is warrented? Serendi^podous 18:59, 23 October 2009 (UTC)

Probably not. Thanks.—RJH (talk) 18:07, 12 January 2010 (UTC)

How Earth Survived Birth

Here's an interesting article about a new simulation of the protoplanetary disk:

Staff (January 12, 2010). "How Earth Survived Birth". Astrobiology Magazine. Retrieved 2010-01-12.

RJH (talk) 18:11, 12 January 2010 (UTC)

I incorporated a summary of this into the article. Please improve the edit if you see a need. Thanks.—RJH (talk) 19:25, 3 February 2010 (UTC)

First recorded use of the term Solar System

The article cites the Webster dictionary, which says that the term "Solar System" is from 1704. However, is it really the date of the first recorded use of the term in general, or just in English? And who and where used it? Jan.Kamenicek (talk) 18:41, 9 March 2010 (UTC)

If you have sources that say otherwise you can add them to the article. Ruslik_Zero 08:46, 14 March 2010 (UTC)

The problem is not that I have a source saying something different. The problem is that the given source does not say this. It is only a dictionary of the English language, so it does not give general information of using the term "Solar System", it gives only the information about its use in the English language. I would change it in the article, but before doing so I just thought I should ask first, whether somebody has info about the real first use of the term. Jan.Kamenicek (talk) 09:04, 14 March 2010 (UTC)

Actually, the source doesn't say whether it's only in English or not. And since I'm unlikely to find a source that goes beyond English (since I speak English), I don't really see how I can solve your problem. Serendi^podous 09:11, 14 March 2010 (UTC)

If the information is so much unclear, I suggest leaving it out. Jan.Kamenicek (talk) 09:14, 14 March 2010 (UTC)

I believe the source is reasonable, though a better one is always welcome. Before Galileo's time talking about the Sun as if it was the center of the Universe was simply a good way to get hung. -- Kheider (talk) 14:49, 14 March 2010 (UTC)

I'd venture that Galileo's "Dialogue Concerning the Two Chief World Systems (Ptolemaic and Copernican" from 1632 is a place to start for the etymology. It establishes that a "world system" in the cosmic sense was the collection of planets, and there were several kinds, the two main contenders being Ptolemaic (Earth-centred) and Copernican (Sol-centred). From there to describing a particular world system (e.g. Copernican) focused on the Sun is a short step. --Sdoradus (talk) 10:23, 10 July 2011 (UTC)

(Fragment of) molecular cloud

The article says that The nebular hypothesis maintains that the Solar System formed from the gravitational collapse of a fragment of a giant molecular cloud that likely was several light-years across.

• Does the sentence mean that the fragment was several light years across, or that the whole molecular cloud was that big?
• The given source states that the whole cloud collapsed, not only its small fragment. If the source is wrong, a different one should probably be used. Jan.Kamenicek (talk) 09:25, 11 March 2010 (UTC)

  It says that an overdensity collapsed, not all cloud. Ruslik_Zero 09:36, 14 March 2010 (UTC)

  I see, sorry, I did not read it well. Thank you for the answer. Jan.Kamenicek (talk) 10:11, 14 March 2010 (UTC)

Clumps of dust

Although it seems that nobody takes care of this article, I will try to ask one more question. In the section Formation of planets it is written that dust grains formed into clumps between one and ten kilometres in diameter. I cannot imagine a clump of dust several kilometres big. May be the unit is wrong. There is also written that these clumps (of up to 10 km) collided and formed larger bodies (of about 5 km!). Jan.Kamenicek (talk) 22:23, 13 March 2010 (UTC)

It's accurate. Keep in mind that "dust" to an astronomer is little pieces of rock, not like the dust in your house. thx1138 (talk) 16:21, 4 April 2010 (UTC)

It also helps to keep in mind that there is a very large amount of space, and the events that birth a star (and its planets) create quite a lot of stuff in a rather small area. Things on the most macro and micro of scales can get a bit confusing, since its incredibly difficult for a human mind to practically envision things of such scopes. Chardansearavitriol (talk) 00:24, 15 March 2011 (UTC)

Scattering the early Kuiper belt

It is written in the article: "This resonance created a gravitational push against the outer planets, causing Neptune to surge past Uranus and plough into the ancient Kuiper belt. The planets scattered the majority of the small icy bodies inwards, while themselves moving outwards. These planetesimals then scattered off the next planet they encountered in a similar manner, moving the planets' orbits outwards while they moved inwards."

However, the given source does not say anything of this kind. Jan.Kamenicek (talk) 15:11, 21 March 2010 (UTC)

It is in ref 29. Ruslik_Zero 19:27, 28 March 2010 (UTC)

Thank you very much for adding and changing the refs. Jan.Kamenicek (talk) 20:16, 28 March 2010 (UTC)

Supernovae influence

The article reads: "The evolution of the outer Solar System appears to have been influenced by nearby supernovae and possibly also passage through interstellar clouds."

However, the given source does not give any information about any influence of supernovae on the outer Solar System. Jan.Kamenicek (talk) 10:12, 28 March 2010 (UTC)

Revised. Serendi^podous 15:04, 23 August 2010 (UTC)

Added latest date estimate of 4.5682 Ga. (No error ranges--can they really date to within a 100 000 years?)

Yes, they can. We can measure time on a scale as small as 10⁻⁴³ seconds after the start of the universe (See: planck_epoch) and can theoretically measure dates of such insane heights as 10³⁰⁰⁰ and beyond. — Preceding unsigned comment added by Chardansearavitriol (talk • contribs) 00:33, 15 March 2011 (UTC)

See my note in 'Chronology Piece' above, where I provided a reference with examples of the extreme precision available from isochron dating. What matters is not so much the range over which measurement can be made, though that is tremendous, but rather the great accuracy possible. This precision has a direct bearing on the ability to make detailed models of Solar System beginnings. For those not familiar with radiological dating methods, I might add that the essential feature of isochron methods which allows such precision is this; you don't need to know the initial concentration of the parent isotope, a problem which constantly confounds other radiometric dating methods. --Sdoradus (talk) 10:32, 10 July 2011 (UTC)

I remember reading that nanodiamonds have been found, which are thought to have formed in the supernova that triggered the collapse of the Solar nebula. Have they been dated? That would more neatly bracket the formation; I'm not clear on how well the formation of Ca-Al inclusions dates the 'beginning' of the Solar System, or even what the beginning would be--the ignition of Sol, maybe? — kwami (talk) 09:39, 24 August 2010 (UTC)

The nanodiamonds are new to me, and I was once qualified in the field. Can you provide a reference? --Sdoradus (talk) 10:40, 10 July 2011 (UTC)

PS. diamonds being pure carbon, the only radiological method possible would be Carbon 14 dating, which depends on atmospheric generation so can't be used for cosmic objects. Besides, a rule of thumb used to be that the limit of measurement topped out at 32,000 years. I see from the Radiocarbon dating article that ~60,000 radiocarbon years is the current limit of the technique; diamonds of great antiquity yield radiocarbon dates of 60-80,000 years BP. --Sdoradus (talk) 10:40, 10 July 2011 (UTC)

PPS the reason a reference would be good is that maybe there are inclusions of some other material, like zircon, within the nanodiamonds. --Sdoradus (talk) 10:40, 10 July 2011 (UTC)

600 B.C.

As it is, the wording of the text implies that Aristarchos of Samos spoke in 600 B.C. Actually, he had not been born then. —Preceding unsigned comment added by 93.97.194.200 (talk) 11:29, 5 April 2011 (UTC)

Well spotted. I think that was a "fossil" from an earlier removed edit that wasn't properly cleared. Serendi^podous 11:33, 5 April 2011 (UTC)

The article here appears to reject receiving new elements

Is it agreed that any alternative to solar nebular hypothesis is not accepted at this article? — Preceding unsigned comment added by Roufeng 2011 (talk • contribs) 03:35, 29 August 2011 (UTC)

Logic dictates that the consensus of the mainstream cosmologists outweighs the opinions of the alternative few – or the one crank! IVAN3MAN (talk) 04:08, 29 August 2011 (UTC)

Introduction

Hi! I'm traslating this articule into portuguese and now I have a doubt. In the beginning of the text, in introduction, 2nd paragraph there is that: "Since the dawn of the space age in the 1950s and the discovery of extrasolar planets in the 1990s, the models have been both challenged and refined to account for new observations." What are the two models? I just read one, I think (nebular hypothesis). The other is the protoplanetary disk? Is that a teory or model? Thanks! Sarilho1 (talk) 18:14, 14 February 2012 (UTC)

I suppose it should say "the model has been"... Serendi^podous 18:30, 14 February 2012 (UTC)

I suppose so, but I wasn't really sure. I think that the "both" is also out no? But thanks, you help me a lot. Sarilho1 (talk) 18:36, 14 February 2012 (UTC)

I understand it "both challenged and refined", i.e. challenged and also refined, not "both models". Jan.Kamenicek (talk) 18:40, 14 February 2012 (UTC)

I don't know! Now I urderstant and now I can build a correct sentence and put right information, because the languages are diferent. Anyway, you should put the sentence to all understand (when I say all I'm referring to english speaking people, because foreign should know if they what to translate), if all english speakers understand, sorry, the error was mine. Sarilho1 (talk) 19:33, 14 February 2012 (UTC)

"Both" refers to "challenged and refined", not the models. It depends how broadly you define "model" as to whether it's singular or plural -- there are many "models" to describe the formation and evolution of the Solar System, but all the ones that are supported by modern data broadly fit within the nebular hypothesis model. —Alex (ASHill | talk | contribs) 22:59, 14 February 2012 (UTC)

Migration and formation of terrestrial planets

The scenario for the formation of the inner planets combined with planetary migration doesn't seem to agree with the scenario that is nicely laid out in the introduction of this paper:

Pierens, A.; Raymond, S. N. (2011). "Two phase, inward-then-outward migration of Jupiter and Saturn in the gaseous solar nebula". Astronomy & Astrophysics. 533: A131. arXiv:1107.5656. Bibcode:2011A&A...533A.131P. doi:10.1051/0004-6361/201117451.

This is referred to in the paragraph at the end of the "planetary migration" section beginning "Another question is why Mars came out so small compared with Earth", but that paragraph seems out of place (probably because it was just glommed on to the existing structure when the research came out). I tried to incorporate that paragraph into the main text but didn't see an easy way immediately -- it looks like it might require structural changes to both the planetary migration section and the formation of planets section. This paper is also relevant:

Walsh, K. J.; Morbidelli, A.; Raymond, S. N.; O'Brien, D. P.; Mandell, A. M. (2011). "A low mass for Mars from Jupiter's early gas-driven migration". Nature. 475 (7355): 206–209. arXiv:1201.5177. Bibcode:2011Natur.475..206W. doi:10.1038/nature10201. PMID 21642961.

As near as I can tell, a consensus has quickly formed that the "Grand Tack" scenario laid out by the Nature paper and expanded upon in the A&A paper above is valid.

—Alex (ASHill | talk | contribs) 05:11, 28 February 2012 (UTC)