Talk:Theia (planet)

Remove most of Collision?
In the wiki it says this: "' Theia struck Earth with a glancing blow[6] and ejected many pieces of both the proto-Earth and Theia. These pieces either formed one body that became the Moon, or formed two moons that eventually merged to form the Moon.[2] Had Theia struck the proto-Earth head-on, it would have led to the destruction of both planets, creating a short-lived asteroid belt between the orbits of Venus and Mars.'" But latest research shows the reverse: That the moon was created by a head-on collision. It did not destroy the earth. https://www.sciencerecorder.com/news/2016/01/28/moon-formed-head-collision-earth-infant-planet-theia/ I am not going to change the wikipage myself, i leave that to someone who has more scientific knowledge and not just reads news articles. — Preceding unsigned comment added by 84.24.79.254 (talk) 20:34, 29 January 2016 (UTC)

Remove most of the details about the Giant Impact Theory?
I wonder if most of the first two paragraphs should be removed? The giant impact theory page does a much better job, and is more likely to be well maintained then this page. netjeff 00:31, 24 February 2006 (UTC)


 * I believe the moon was created by Allah separately than earth so was the sun and earth. Stop mocking Islam by you hypothetical stupid imagination
 * The Qur'an further states that Allah created the sun, the moon, and the planets, each with their own individual courses or orbits. "It is He Who created the night and the day, and the sun and the moon; all (the celestial bodies) swim along, each in its rounded course" (21:33 2A00:23C7:949C:A901:946A:4911:239A:90AE (talk) 16:32, 8 September 2023 (UTC)
 * If only all constellation bodies were so perfectly set in their places, and so well described. Ask yourself about Sagittarius A. La Grange points. The Oort cloud. You say little but presume much. 23.121.67.196 (talk) 08:31, 15 November 2023 (UTC)

I think you're absolutely right. So I did it. hyperionred 30 June 2006

Documentary
This planet and its collision with Earth is the subject of a documentary on Channel 4 right now. HTH HAND —Phil | Talk 21:30, 24 November 2008 (UTC)

poetry?
The whole 'marriage - kiss - embrace' bit of the Before Collision section is a bit... well, poorly written in my opinion. More opinion/facts and less poetry would be helpful —Preceding unsigned comment added by 195.69.214.5 (talk) 20:29, 13 December 2008 (UTC)


 * Agreed. So edited. Mikaey (talk) 06:19, 20 December 2008 (UTC)


 * Again .... Its not well written ... It may confuse the readers. SSJ 5 (talk) 02:18, 6 January 2009 (UTC)


 * I have struggled with the poetic imagery as I felt that Thea and the collision lent themselves to it. it is important to try to use descriptive or poetic language in science. This should be encouraged so that the unscientifically-university-trained minds(children)who look to Wikipedia might grasp the drama of science. I have edited it myself as well. The material of Theia was married to earth and the earth embraced its destiny etc. The kissing part well it was more of a smack to the kisser.  —Preceding unsigned comment added by Rogerspeed23 16:22, 19 January 2009 (UTC)
 * This is an encyclopedia, not a children's story book. NJGW (talk) 17:10, 19 January 2009 (UTC)

Encyclopedias were written to be accessible by children. Wikipedia by definition was a quick venue and primary source that offered a accessible source of evolving verifiable information. Primarily a wiki is accessible and understandable by folks who aren't formally trained, lettered and otherwise self important- like children. Rogerspeed23. I will try to create some sources to this article in the next few days and weeks.

The movement of the planets and the mathematics of their creation is poetry in motion. Oh and mother nature has been a real bitch lately along with cox.net who killed my connection over the last week. Ice storms in Arkansas have hammered us.

Redirect the page?

 * The following discussion is closed. Subsequent comments should be made in a new section.

The Giant impact hypothesis page covers all information here properly, making this page, in its current form, unnecessary. 128.252.20.65 (talk) 00:15, 13 January 2009 (UTC)
 * I'm in favor of merging and redirecting, though deletion is right out. There doesn't appear that anything can be at this location beyond the fact that it is a name appearing in a promonent hypothesis.  Any objections?  NJGW (talk) 20:15, 15 January 2009 (UTC)

Discussion location: please discuss this suggestion here. NJGW (talk) 02:35, 17 January 2009 (UTC)


 * The above discussion is preserved as an archive. Please do not modify it. Subsequent comments should be made in a new section.


 * Can we bump this discussion. In comparison to the Giant Impact Hypothesis, this article in its current state is scientific garbage. I have done a quick cleanup, but personally I'd much rather see the whole thing get the chop.--EvenGreenerFish (talk) 09:49, 6 September 2015 (UTC)

What Garbage
"...if the impact were not glancing, it could have destroyed Earth." That depends on the velocity, as well as mass. If Kennedy wasn't assassinated, he could have started world war III. Point is, it is complete speculation and vague rubbish. This article is junk. "Glancing" isn't defined, as one example. Seems to me the dynamics of the collision aren't necessarily just limited to "head-on" or "glancing"...especially since the article suggests that Earth and (hypothetical) Theia were gravitationally interacting. This article also claims the Earth's core is partly from Theia, at the same time as claiming the collision was "glancing". Incoherent is putting it mildly. The use of words like "flew" to describe the ejecta from the collision is also lame. Theia's debris gathered and formed the Moon, huh? So, in other words after a 'glancing' blow, Theia's mass magically shrunk by a factor of 10 and magically none of the Earth's mass was incorporated into Luna?? Of course, isotopic composition directly contradicts the latter. This is really poorly written. Obviously Theia is a necessary part of the Giant Impact Hypothesis, and some duplication is necessary. I doubt if its necessary that Theia and protoEarth were in a stable orbit around Sol, let alone that Theia occupied L5 or L6. (Is it meaningful to even talk about the Lagrangian points when the masses are so close (ie 10:1)??) If this is the "leading" candidate to explain the Earth/Moon system, then surely a better job can be done explaining it. As an aside, the Giant Impact article admits that there isn't any consistent explanation to explain a single Moon starting with a giant impact. And the illustration in that article clearly depicts a "head-on" collision. (What it means by "indirect" collision, I leave for others to clarify.) If anyone is motivated to fix THIS article, the section "Basic Model" of the Giant Impact article would be a good place to start. This needs a near total rewrite. One thing I'd certainly do is point out that the idea has gained some credibility by explaining some of the isotopic similarities between Luna and Terra, as well as explaing some of the unusual spin and tilt properties of Earth.173.189.76.72 (talk) 19:29, 10 April 2015 (UTC)

Propose move to Theia (hypothesized protoplanet)
The title is misleading as it assumes the existence of Theia as a planet whereas it is a hypothesis. Even if it existed, it would not have been classified as a planet as it had not cleared its path. It would most have been a protoplanet or a dwarf planet, and not a planet.--EvenGreenerFish (talk) 02:44, 2 September 2015 (UTC)
 * Sources call it a planet. If you have an issue with that, then take it up during the next scientific conference. JOJ  Hutton  03:22, 2 September 2015 (UTC)
 * Any source that refer to it as a planet would not be reliable sources. This is simply not my personal opinion, it is a well known scientific fact. In any case, I checked the source. The first source describes it as: "a Mars-sized body", "When the protoplanet had grown to be about the size of Mars" and "planet-size object". Only one source, History.com, mistakenly refers to it as a planet, personally I think it highlights that History.com is not a reliable source for astronomy facts. I will source some reliable academic citations.--EvenGreenerFish (talk) 09:30, 6 September 2015 (UTC)
 * So any source that doesn't fit into the pre conceived notion that Theia was not a planet is "not a reliable source". I think you need to read what reliable sources are.-- JOJ Hutton  13:55, 6 September 2015 (UTC)


 * I am familiar with Wikipedia's policies thank you. Perhaps you should regard the policies that state "Each source must be carefully weighed to judge whether it is reliable for the statement being made in the Wikipedia article and is an appropriate source for that content" and "For information about academic topics, scholarly sources and high-quality non-scholarly sources are generally better than news reports. News reports may be acceptable depending on the context. Articles which deal in depth with specific studies, as a specialized article on science, are apt to be of more value than general articles which only tangentially deal with a topic.". You're missing the point. If Theia was a planet, it would not have collided with Earth ... the article itself states that:
 * Theia orbited the Sun at around the orbit of Earth at the L4 or L5 Lagrangian points
 * This is not the definition of a planet, a planet cannot orbit in a Lagrangian point, only a moon or a trojan can do that. The trojan may be of planetary mass, but it definitely would not be a planet.--EvenGreenerFish (talk) 07:57, 24 September 2015 (UTC) & Jerzy•t 23:31, 31 January 2016 (UTC)
 * I have corrected EGF's formatting, (but not altered any content) in their preceding contrib, esp'ly to eliminate the appearance that only the last 'graph was their contrib (and the rest was a separate, unsigned contrib -- which only the hx entry is able to rule out). (I am also doing my best to correct the succeeding confused indentation, by reading the mind of our colleague K-K1 the best i can.) --Jerzy•t 23:31, 31 January 2016 (UTC)


 * Both seti ("In the animation, Earth and the smaller planet that hit Earth, named Theia,...") and NASA ("NASA's twin STEREO probes are entering a mysterious region of space to look for remains of an ancient planet which once orbited the Sun not far from Earth.") have called it a "planet". Which doesn't mean it actually fits the definition, just that "planet" is a convenient shorthand for "planetary mass object" when speaking to a general audience. I suggest we put in a sentence or two explaining that it isn't a planet but is often called a "planet", but that would have to be sourced. I'm leaning against renaming the article. Kendall-K1 (talk) 11:47, 24 September 2015 (UTC)
 * It is just lame to use "NASA's or SETI's PUBLIC RELATIONS OFFICES as authoritative sources for SCIENTIFIC/TECHNICAL subjects. I'd suggest we include a note and start off with "planet sized object" and then use the more friendly language with the note. Spending too much time arguing whether a hypothetical object can be classified as a planet is way too far into the weeds, imho. Pluto is still commonly called a planet in the technical literature (and there are on-going attempts to get it reclassified). Language can't be constrained by what any one organization demands; it also requires widespread consensus in use. I also note that what is true for the current solar system (and the experts who study it) may not be true in the smaller area/niche/specialization of those studying historical Earth/Moon and its/their origins. Does it really matter? (as has been pointed out elsewhere, there are zero objects (in our Solar System) which have completely swept their orbits. In fact, it isn't possible. Nor is the term defined. So, the argument that Pluto isn't a planet because it hasn't swept out its orbit can also be applied to Earth or Jupiter, producing ridiculous results.)72.16.99.93 (talk) 21:30, 17 January 2019 (UTC)

Grammatical conjunction applicable to L4/L5
We have
 * Theia is thought to have orbited in the L4 or L5 spots in the Earth's orbit. It grew to a Mars-like size and, through gravitational perturbation from Venus, was moved around and eventually set on a collision course with Earth.

surely by someone imitating a source saying
 * ... could have grown large enough to produce the Moon if it formed in the L4 or L5 regions

or
 * ... orbited the Sun at around the orbit of Earth at the L4 or L5 Lagrangian points

but that raises the question of why they thot they should edit when they lacked the conviction to look for a source that managed to state the situation in a way that doesn't violate the principles of English grammar. The question is sharpened, tho YMMV, by my first page of hits for theia l4 l5: I'm forced to ask myself whether editing WP for 10+ years has made me stupid, or cowardly. Perhaps i should not risk spoiling the experiment by announcing it here, but let's see what ensues.... --Jerzy•t 05:20, 1 February 2016 (UTC)
 * 1)  Theia would have been nudged out of L4 or L5
 * 2) The STEREO spacecraft are entering the L4 and L5 Lagrangian point[s, each centered about 93 million miles away along Earth's orbit.] (The bracketed portion was not extracted by Google, and i visited the page to verify what i expected.)
 * 3) (images, no text)
 * 4) Theia is thought to have orbited in the L4 or L5 spots in the Earth's orbit. (Never mind, WP is not a reliable source.)
 * 5) Later, Theia would have been nudged out of L4 or L5 by the ...
 * 6) Whether Theia exists, the L4 and L5 points are attraction wells for interesting space clutter ...
 * 7) About 4.5 billion years ago when the planets were still growing, this hypothetical world, called Theia, may have been nudged out of L4 or L5 by
 * 8) They point to the Trojan asteroids at Jupiter's L4 and L5 points and similar objects ... (Note this is about Jupiter, where objects have been observed both at its L4 point and its L5 point.)
 * 9) Call it 'Theia,' a hypothetical planet that may have formed in our system's earliest era. And place it for argument's sake at either the L4 or L5 ... [point, where the gravitational influences of other developing planets like Venus may have destabilized its orbit, accounting for the subsequent impact.]
 * 10) A well known example are the Trojan aseroids at the Sun Jupiter L4 and ... III proposed that Theia coalesced at the L4 or L5 Lagrangian point, where the gravitational influences of other developing planets like Venus may have destabilized its orbit, accounting for the subsequent impact.

Colliding-worlds image
is captioned
 * Artist's depiction of a collision between two planetary bodies similar to the hypothesized proto-Earth and the smaller, Mars-sized object - Theia."

using the weasel word "similar", presumably on the premise that the interaction between our moon and Mercury (with "very great speed", BTW) which is abusive in suggesting "so great that all you need to know is that their closing velocity being 10 times greater wouldn't have significantly changed the appearance", and depicts the smaller body maintaining its shape even tho the larger one's impacted hemisphere is mostly shattered away already. Now, that kind of collision just might be sensible in our case, since Earth's dynamic interior may well make it more shatter-prone (now, anyway) than Theia was then, but the claim that there even is any similarity in appearance between collisions with similar diameter ratios is not just unverified but far-fetched, since vulnerability to astronomical collisions depends very heavily not just on composition but on effects that are not linear with diameter. IMO the value of this image in the context of this article corresponds, in the absence of verification of relevance, to that of one on the cover of an Immanuel Velikovsky colliding-worlds paperback: primarily emotional and obscuring the vagueness of the facts. When we have verification of definable relevance for this or some other drawing, then great. For now, the picture is worth a thousand words but we have no idea how many of the words are true. --Jerzy•t 07:50, 4 February 2016 (UTC)

From Earth to the Moon: a usage query
My unresearched opinion is that "the Earth" sounds stilted in most contexts (presumed special case: From the Earth to the Moon by Jules Verne) but i'd expect "Moon" to at least momentarily evoke e.g. "Oh, do you mean 'the Moon', or are you talking about the founder of the Moonie church?" In SF contexts, "Luna" is common (and i don't hesitate to use it in technical discussions where it may be helpful if more than one moon is under discussion -- but maybe that's one of my weirdnesses). Completing the pattern, "He fell to earth" means "he collapsed on the ground" (unless context favors the the David Bowie character). Even "the Earth and the Moon" sounds stilted and "Earth and Moon" could almost be a good choice to join Sky & Telescope, so i guess i'm pretty much advocating that the conventions "Earth" and "the Moon" respectively be used consistently in the accompanying article (and perhaps others but with the expectation that there are bound to be special cases where it works badly). Other thoughts? --Jerzy•t 22:33, 4 February 2016 (UTC)

"A Trojan point" means "L4 or L5"
I complained above about the bizarre language (a) colleague(s) were using to say "either at L4 exclusively or at L5 exclusively, tho we don't know, and may never have a clue, which" (that being what i'm pretty damn sure is the only currently plausible description of where Theia had been on its way from a Lagrange point -- since it would be incredibly bizarre if the last one it had been detectably influenced by were L1, L2, or L3). I finally got reminded that tho the Trojan and Roman asteroids (or whatever that junk is classed as) of Jupiter cluster (respectively, or if not, then vice-versa) as one group around its L4 and another around its L5, both those points are described as "Trojan points". So i think the easier terminology we need to write well, and the easier to understand, is along the lines of "at one of the Trojan points of the Earth-Sun system" (or i think with the same meaning but simpler) "at one of the Trojan points of the Earth's orbit"). --Jerzy•t 23:03, 4 February 2016 (UTC)
 * Oh yeah, maybe i'm the clueless jerk, but i can't remember all the terminology for different "grades" of equalibrium: it seems to me our Lagrange point and Trojan point articles may both misuse "stable" -- don't at least two of L1 thru L3 constitute points of unstable or metastable or quasi-stable or neutral equilibrium? (I suspect this will be answered here quicker than at one of those other two articles' talk pages, so i'll keep reminding myself to follow this discussion, and post the same question there once this goes quiet again.) --Jerzy•t 23:48, 4 February 2016 (UTC)

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Article needs a Criticism section
There is evidence FOR the Great Impact hypothesis but there is also evidence AGAINST it. It is true that it is widely viewed as the best hypothesis (or family of hypotheses) we have for the origin of the Earth (as it exists today). But it is also true that quite a few experts do NOT find the evidence persuasive and a number have published evidence which contradicts the hypothesis (or seems to). My sense is (as of early 2019) that the hypothesis is less likely to be true (in a Bayesian sense) today than it was a decade ago. I'd suggest a table for the pros and cons. With the pros including the evidence/observations that support the Great Impact and the cons including evidence that (apparently) weakens it. (This may be difficult, because typically a hypothesis is like water running downhill, block it here (find evidence that contradicts a particular aspect), and it will find the easiest (closest) alternative pathway. The Great Impact has all sorts of variations and adjustable parameters. (in common with most weakly constrained model systems). It is vastly less developed than the Standard Model of Particle Physics or the Standard Cosmological Model (lambda-CDM).72.16.99.93 (talk) 21:45, 17 January 2019 (UTC)

Move to Theia (hypothetical planet)?
Why does this article's name not match with other articles on proposed solar system objects? Theia is no less hypothetical than any of the others (opening line of the article: Theia is a hypothesized ancient planet). This should be an uncontroversial move. --143.167.6.197 (talk) 09:41, 9 September 2019 (UTC)
 * Chiron (hypothetical moon)
 * Neith (hypothetical moon)
 * Nemesis (hypothetical star)
 * Phaeton (hypothetical planet)
 * Theia (planet)
 * Themis (hypothetical moon)
 * Tyche (hypothetical planet)
 * Vulcan (hypothetical planet)

What happened to Theia?
I came here from the page on Giant Impact Hypothesis to see what became of Theia after collision. But neither page makes any reference to that effect. Extended bodies, on collision, recoil and move on with or without loss of their material. Since nothing is mentioned of the present state of the protoplanet Theia, shall we understand that the two protoplanets merged, and apart from the loss of material that became the moon, survives as the present Earth? Nidhishunnikrishnan (talk) 11:27, 14 May 2020 (UTC)


 * Perhaps could mention the Large low-shear-velocity provinces origins theory (the second one) - currently it's only linked one-way. Technicality nitpicker (talk) 17:53, 10 October 2021 (UTC)
 * I tend to agree with that 2601:680:C000:6EC0:3DA6:2AE4:533D:8804 (talk) 23:56, 24 May 2023 (UTC)


 * This recent video seems to explain what happened to Theia, that it indeed became part of Earth and the Moon: https://www.youtube.com/watch?v=X-EZjEJc8Bo

Dionyseus (talk) 07:46, 5 July 2021 (UTC)

More deep story here.

Later considerations in 2022
In the last two years a couple updating articles regarding the collison of Theia and protoEarth have emerged. These accounts seem to be well researched and differ from the Wiki content as of 7/2022. For instance, Wiki said the earth's water was largely supplied by Theia. Now recent research says it was probably dry. Also, there are large structures in the Earth that might well be still intact fragments of Theia. How about that? Also, the next manned missions to the moon might be aiming to land near the Southern pole, where it is believed to be still intact fragments of Theia. And one article mentions that Theia may have been an accreted body, itself a bunch of collided accumulations, the size of the Earth. 2601:1C2:4E00:2100:B579:D715:804E:1A1E (talk) 07:52, 26 July 2022 (UTC)