Editing Talk:2925: Earth Formation Site

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The title text is only true for geocentric latitude and longitude, not geodetic (which is what is commonly used). [[Special:Contributions/172.69.58.125|172.69.58.125]] 18:32, 26 April 2024 (UTC)

I'm impressed that whatever distant body that sign is placed upon, has actually developed plant life. Especially since it would need to be parked in place relative to the rest of the observable cosmos, & thus seems unlikely to have a suitably close star making regular appearance overhead...   
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 19:11, 26 April 2024 (UTC)
:👍[[User:Tier666|Tier666]] ([[User talk:Tier666|talk]]) 09:52, 28 April 2024 (UTC)
::Magrathea?  [[User:L-Space Traveler|L-Space Traveler]] ([[User talk:L-Space Traveler|talk]]) 14:46, 27 April 2024 (UTC)
: Hi Proph! I just wanted to say that I enjoy reading your comments here and in the SMBC comment page, if you are in fact ProphetZarquon in both places. [[Special:Contributions/172.70.175.28|172.70.175.28]] 21:46, 26 April 2024 (UTC)
::If there's another Prophet Zarquon out there - wait, nope, looks like that's me, too...
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 03:25, 27 April 2024 (UTC)

:The spatial location of a famous person's birth is technically not where the Solar System now is, also.  If you're going to be picky about that.  If you do allow the Earth's worldline to be accounted for, then it's broadly true that Earth formed (looks out of window at home) here.  I think the principle concern there is whether Earth formed in the collision of planets named Ear and Theia, or whether Earth was Earth before Theia came along, which either way seems to be why there is such a large Moon beside it - made of material from both of the previous planets. And it probably counts as a change of course from the previous situation, although the apparent likelihood that Theia formed in Earth's orbit in originally a Trojan relationship may bear on that - if one planet just caught up with the other in orbit, like tailgating in traffic.  Robert.Carnegie@gmail.com [[Special:Contributions/141.101.98.184|141.101.98.184]] 17:35, 27 April 2024 (UTC)

The ridiculously specific date may be a reference to how real historical markers frequently get dates incorrect [[Special:Contributions/172.70.127.135|172.70.127.135]] 23:29, 26 April 2024 (UTC)

The other side of the sign says, "At this exact point in space, 13.7878693 billion years ago, the Big Bang took place." That's true of every point in space, according to the current model. The Big Bang implies that all of space was a single point, and space itself expanded outward from that point. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 03:07, 27 April 2024 (UTC)


The explanation needs to be rewritten. It is missing the point and far to detailed for just saying: The marker could be standing at any point of earth's surface, as reinforced by the title text. The whole discussion about galaxies and solar systems moving is just a matter of the reference system and does not contribute to the understanding of the comic.--[[Special:Contributions/172.70.243.32|172.70.243.32]] 07:28, 27 April 2024 (UTC)
: I disagree. The section is saying that it could not have reasonably happened on Earth itself due to the fact the Earth and the Solar System itself move around through space. <span style="font-family: 'Comic Sans MS'">[[User:SomeoneIGuess|someone, i guess]]<sup>([[User talk:SomeoneIGuess|talk i guess]]&#124;[[Special:Contributions/SomeoneIGuess|le edit list]])</sup></span>  13:25, 27 April 2024 (UTC)
::Randall was once a physicist. He's aware of the fact that there is no absolute system of measurements, and that locations on Earth are always relative to Earth coordinates, not some sort of galactic map. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 14:10, 27 April 2024 (UTC)
:::Can you be 'once a physicist'? Once you've been a physicist, aren't you always a recovering physicist?[[Special:Contributions/172.70.90.92|172.70.90.92]] 16:31, 29 April 2024 (UTC)
::More immediately, it could not have reasonably happened on Earth, since Earth didn't exist until it happened.[[Special:Contributions/172.69.195.3|172.69.195.3]] 10:53, 29 April 2024 (UTC)
: I wholeheartedly agree. The whole joke, as reinforced by the title text, is that the marker could be anywhere on Earth. Simplify, simplify.[[User:DKMell|DKMell]] ([[User talk:DKMell|talk]]) 16:21, 29 April 2024 (UTC)

Can the Earth's core even have a latitude and a longitude? Aren't those all referring to the surface? --[[Special:Contributions/162.158.90.198|162.158.90.198]] 11:47, 27 April 2024 (UTC)
:You're right. That is the joke, in fact. [[User:Nitpicking|Nitpicking]] ([[User talk:Nitpicking|talk]]) 14:10, 27 April 2024 (UTC)
:Well, 162.158... is 'right' except that you ''can indeed'' have a latitute, longitude and also ''altitude/depth'' on top, not just restricting yourself to the surface (or Mean Sea Level or whatever other geometric surface you consider as your default).
:As to whether the (centre of the) core can have latitude and longitude, it's a very similar argument as that of whether the (coordinate) poles can have longitudes as well as ±90° latitude.
:If you are asking what either pole's longitude is, it would depend upon the what the algorthm was specified (or fails to have been) for the situation, as you could be told 'undefined', 'NaN', given a placeholder constant (e.g. zero), an effectively random value, a value determinate upon what led to this (you were at <location>, 10 miles south of the north pole, and modified that by 10 miles direct northwards travel, so maintain the same longitude as <location> had), a value that would normally be out of range (e.g. for silently passing on, to do the error-catching/checking later on) or several other options.
:If you're ''specifiying'' the longitude of a pole (for use in an onward algorithm) then it may well (or may not!) be possible to provide any/all of these, but perhaps ultimately ignored/chucked away as meaningless. (Unless you have it doing something like "go ten miles south from north pole, what's the <location> now?", intentionally or otherwise disambiguating via the 'arbitrary but definite' polar longitude.)
:So, similarly, if you're asking "What lat/long is the location of the core", the chances are that you're going to get to go through a different manner of deriving a result from that of requesting information such as "This is my lat/long. Is this (above) where the core is?".
:...though, yes, this still ''is'' very much the joke. Including all the ambiguity as to the rationale involved in however it apparently became disambiguated. [[Special:Contributions/172.69.195.122|172.69.195.122]] 21:59, 27 April 2024 (UTC)

It's a [https://www.explainxkcd.com/wiki/index.php?title=2925:_Earth_Formation_Site&curid=27482&diff=340784&oldid=340779 valid edit], as it goes, but the ''reason'' seems a little over-omniscient. Speaking from another country that does 'signs' quite a bit (for visibility, as well as strategically placed 'table'-style info for closer perusal), I'm not sure we can say it's anywhere near uniquely US-practice. [[Special:Contributions/141.101.99.120|141.101.99.120]] 10:28, 29 April 2024 (UTC)

The explanation talks about the impossibly precise date on the sign, but it's ''not'' highly precise. It's 4,450,000,000 BCE, which as far as we can tell is precise to the nearest 10 million years, or even 50 million - hardly an exact year. (The precision could have been made clear with scientific notation like 4.45x10<sup>9</sup>, but that's not something you'd put on a sign for the general public.) Rounding to the nearest 10 million years matches the precision of [https://pubs.usgs.gov/gip/geotime/age.html what we know about the formation of the Earth], so it's not unreasonably precise. If Randall had wanted to make a precision joke, he would have used "4,450,002,024 years ago" or something along those lines - something that pegs Earth's formation to a specific year. [[User:DKMell|DKMell]] ([[User talk:DKMell|talk]]) 16:52, 29 April 2024 (UTC)
:Firstly, you top-posted. Moved your contribution down here.
:Secondly, 4.45x10<sup>9</sup> only makes clear the imprecision (c.f. "4.450000000x10<sup>9</sup>"). Whereas it would be entirely possible for something to be ''precisely'' in the year 4,450,000,000 BCE, as much as it could be 4,450,000,001 BCE or 4,449,999,999 BCE. 
:Of course you could 'creatively lie' to imply the correct precision (at the expense of the correct accuracy), as in the last paragraph of {{w|Mount Everest#19th century|this section on surveying a certain height)... Or you could instead say that it was 4,450,002,023 years ago, but then you'd have to update/replace the sign at some point in 2025. [[Special:Contributions/172.71.242.206|172.71.242.206]] 19:49, 29 April 2024 (UTC)

Not sure what astronomical standards [https://www.explainxkcd.com/wiki/index.php?title=2925:_Earth_Formation_Site&diff=prev&oldid=340919 are inconsistent in this removed text]. We can measure (historic) times in terms of a unit exactly 31,557,600 seconds long, the Julian year, even before its establishment. Yet appreciate that a physical (astronomically accurate) solar year ''at'' that historic time may be different, especially prior to the Thea-collision which probably did ''something'' (could depend upon if Thea had originated from L4 or L5, or what dynamics it possessed if it came from elsewhere), perhaps easily by the requisite amount to build up the nearly 2% difference. Seperately (and unrelated to the actual definition(s) of year), day length has also been changing, thus we know that a physical solar day has been other than 86400 seconds (astronomical day of 86164ish seconds) and a solar year unlikely to have been 365.25 (or 365.2425!) days, so divorcing ephemeris measurements of time (officially 31,556,925.9747 seconds per year in 1900, and changing still) from SI standards of time (as above) is already a thing.
<br/>The prior edit removing the Thea-impact-moment idea, I agree more with. Though it ''does'' solve the issue of a definitive time and (to some extent) surface location, undoubtedly kicked off the creation of 'nu-Earth' out of the resulting gas and dust and the rest (that didn't get chucked into orbit, to be the Moon, or beyond it to add to the rest of the LHB material). And happened at very much around the time stated by the sign. Given that it's not even supposed to have a real 'answer' to what it means, Thea might well be the answer Randall didn't even think he was leading us to. [[Special:Contributions/172.70.160.173|172.70.160.173]] 17:49, 30 April 2024 (UTC)