explain xkcd - User contributions [en]

Talk:2807: Bad Map Projection: ABS(Longitude)

2023-08-05T20:27:22Z

MDwayne: Canada \(^,^)/

...actually, there's quite a bit of 'foldover' that's covered by the Atlantic, but it's still not quite so much as the Pacific gap across the ±180° edge-to-edge, so forgive me if consider the likes of places in India partnered with the over-adopted American locations as being trans-Atlantic (and across the whole width of Africa and some of the Indian Ocean too) rather than anything else. It could definitely do with a more precise analysis/description, though. Plus how bits of western Western Europe are folded over onto more-central Western Europe (not a very good mirror of Scotland, I think, but I'm particularly more familiar with its effective profile than Randall has any reason to be). [[Special:Contributions/172.71.242.195|172.71.242.195]] 01:20, 27 July 2023 (UTC)
This would make a great EU4 mod [[Special:Contributions/172.68.146.52|172.68.146.52]] 01:21, 27 July 2023 (UTC)

Oh, good, thank you. I on ABS I couldn't get past antilock brakes. And the picture spam from the other day seemed to be tendeon repair. Looked like a surgicical procedure to to fasten cut tendons back together but I didn't see a cast to prevent movement. Shrug. Quite gross, as all surguries are. Poorly of course couldnt see all of the pic.[[Special:Contributions/172.71.222.70|172.71.222.70]] 02:35, 27 July 2023 (UTC)[[Special:Contributions/172.71.222.71|172.71.222.71]] 02:57, 27 July 2023 (UTC)

Added a very basic transcript because this comic is a little too complicated for me and it's my first time. Also, we need more positive vibes considering the previous comic about anti-vaxxers and the... interesting comments in the discussions.

Also, the Galapagos being near to Singapore (that's where I live) would be interesting! [[User:R3TRI8UTI0N|R3TRI8UTI0N]] ([[User talk:R3TRI8UTI0N|talk]]) 03:48, 27 July 2023 (UTC)

This map does not appear to be particularly…correct. For instance, Seoul, South Korea, is given as about 38N/155. But actually it is at 127E longitude. That's nowhere close. On a real map, 155E longitude is several hundred miles east of Japan into the open Pacific ocean, approx. the longitude of the Marshall Islands (but far north of them). Closer to home, for Randall and for me, Boston is given as about 59, but it is really 71W. What's up with that? Is everything shifted…and why? [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 05:00, 27 July 2023 (UTC)

:Oh, wait. I was reading the coordinates like it was a cartesian plane, like on a Lambert or Mercator projection. But in retrospect this is some kind of elliptical projection ({{w|Robinson projection|Robinson}}? {{w|Winkel tripel projection|Winkel tripel}}?) such that the longitude lines are bowed out, further as you get away from the center (here 90°, I guess). That is...too hard for me to read with precision without doing too much math and drawing lines (so I guess I'm lazy), so, probably it's just fine? I dunno. [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 05:09, 27 July 2023 (UTC)
:: This projection keeps the lines of latitude horizontal, allowing the lines of longitude to "bend", with only 90 degrees being vertical. 90 degrees, east/west, it doesn't really matter for this projection. [[User:Nutster|Nutster]] ([[User talk:Nutster|talk]]) 14:12, 27 July 2023 (UTC)

I just quickly put together an abs(longitude) "projection" image based on a real (public domain) map, to show what this would look like more realistically, with overlap. Are home-made images allowed? I cannot upload though ("You do not have permission to create new pages"). Is this because I'm a new user or are uploads prohibited for most users? [[User:Mtcv|Mtcv]] ([[User talk:Mtcv|talk]]) 07:41, 27 July 2023 (UTC)
:It's just your newness (but I'm not sure how un-new/whatever you need to be). But I've 'sent in' things, before, by using some other public image host (not actually being new, but never having had the account here so of course the site won't accept my IP source - for good reason) and allowing an established uploader to spot the link, grab it and submit it locally by proxy if they thought it worthwhile.
:I'm already half tempted to do an ABS(Latitude) for my own ennoyment. Maybe even combined with the above (might be too busy, though, as I mentally model how the Eurasiamerindiafricaustralian subercontinent wouldn't leave much room for recognisable land-mass coastline). Further arbitrary overlapping transforms could also be fun, and perhaps even 'wrong but rational-looking'. [[Special:Contributions/172.70.90.165|172.70.90.165]] 08:16, 27 July 2023 (UTC)

::I see, thanks for the info! Well here's a link: [https://i.ibb.co/TRTW1nq/abslongitude.png]. It's not that interesting, but to me it clarifies where North America has gone, all swallowed up by Asia. Better versions than this are certainly possible. I can add the image's info if someone uploads it. Absolute latitude sounds interesting too. [[User:Mtcv|Mtcv]] ([[User talk:Mtcv|talk]]) 08:44, 27 July 2023 (UTC)

All technical analysis aside, this map is really cool and would make a fantastic fantasy setting.

So... Lemuria was South America all along! [[User:Shirluban|Shirluban]] 12:20, 27 July 2023 (UTC)

*There's a misspelling on the map: "Aleutian" is misspelled as "Aelutian". --[[Special:Contributions/172.70.127.80|172.70.127.80]] 15:02, 27 July 2023 (UTC)
* Reykjavík is misspelled as Reykjavic. Makes it kinda Serbo-Croatic-looking. --[[User:Coconut Galaxy|Coconut Galaxy]] ([[User talk:Coconut Galaxy|talk]]) 16:47, 27 July 2023 (UTC)

Gondwanaland explained as a coordinate error.
[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 15:06, 27 July 2023 (UTC)

The formula added in the "Correct formula" section of the explanation is not consistent with how Randall has overlaid the negative longitudes on top of the positive longitudes. This section was added by an anonymous editor. This formula mirrors the negative longitudes into positive longitudes but leaves them in a separate hemisphere from the positive longitudes, without overlaying the two hemispheres as Randall has done. I think this section needs to be removed completely. Anyone else agree? [[User:Ianrbibtitlht|Ianrbibtitlht]] ([[User talk:Ianrbibtitlht|talk]]) 19:29, 28 July 2023 (UTC)
:I edited it. Not the author, but I think the intent was that this is what correct formula ''should'' have been used, instead of the "whoops!" indident where he actually used abs().
:So I made it more clear (or, possibly less, you decide), plus added another alternative positive-normalising form of formula.
:Though the use of mod (or % operator) may depend upon the mod-function implementation involved (whether it even needs the +360, can handle float longitudes, can perhaps even work well beyond -180..+180 input...) but it *can* be the much clearer method. Just test it with various values from all quadrants (and beyond +-180) ahead of time to make sure (what the comic map's creator should have done with ''their'' method).
:Or, in code, just run something like <code>while (lon<0) {lon+=360}; while (lon>=360) {lon-=360};</code>, or however that'd work in your chosen coding dialect's syntax. And you might need to accept a possible bit of loop-spam if the input is somehow vastly high/low, but it works well in skipping over entirely unnecessary multiplative/divisive operations (it'll do no more than one of the loops, on the way past).
:TMTOWTDI, though, and the usable methods are practically unlimited, I'd probably use whatever method looks good against the surrounding code (or shuttle it away into a subprocedure call, where I now make it look neat alongside its fellow subs).
:Anyway, I think that section isn't necessary, but it may be of interest. [[Special:Contributions/162.158.74.63|162.158.74.63]] 21:25, 28 July 2023 (UTC)

I wondered why it got so frigid and hard-to-breath overnight. Thanks a lot, Randal, for moving me to the Himalayas.[[User:These Are Not The Comments You Are Looking For|These Are Not The Comments You Are Looking For]] ([[User talk:These Are Not The Comments You Are Looking For|talk]]) 02:23, 1 August 2023 (UTC)

== an ABS(Latitude) map ==

After looking at this map, I wanted to see, what an ABS(Latitude) map would look like and [https://imgur.com/LzOp15b this is what I quickly threw together].

Unsurprisingly it doesn't change the world as much, since most of the land mass is on the northern hemisphere. The former South America has now created the worlds largest inland lake in the form of the Caribbean Sea and the Gulf of Mexico but the Panama Canal is still intact. Africa mostly folds up on itself and Australia is now the land bridge between China and Japan. However it was a fun and quick thing to do and I thought I should share it here.

:Can you do abs(log), abs(lat)? [[Special:Contributions/162.158.110.142|162.158.110.142]] 14:22, 27 July 2023 (UTC)

This would actually make a great fantasy map, as my father pointed out. Just swap out the city names with fantasy ones, and players would not be able to figure out where you got the map from. [[Special:Contributions/172.70.114.141|172.70.114.141]] 14:41, 27 July 2023 (UTC)
:Even at first glance it looks faked up though, because half the paisleys are backward.
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 15:06, 27 July 2023 (UTC)

I'm in Serbia and nothing changes for me. I wonder how the Indian subcontinent and Central Asia are dealing with the sudden Americans. [[User:Andrewtheexplainer|Andrewtheexplainer]] ([[User talk:Andrewtheexplainer|talk]]) 15:27, 28 July 2023 (UTC)

As a Canadian of course I would notice this. It appears Canada has the most references on the map with seven just ahead of the USA with only six. Given our typical low self esteem, we take our "wins" whenever we can: thanks Randall [[User:MDwayne|MDwayne.ca]] ([[User talk:MDwayne|talk]]) 20:27, 5 August 2023 (UTC)

Talk:2783: Ruling Out

2023-06-04T18:52:29Z

MDwayne: Near earth exoplanet

Wow. the amount of citation needed tags is excessive. Here's a fun idea, do like that SMBC comic and actually find and give citations. [[Special:Contributions/172.69.70.72|172.69.70.72]] 19:41, 31 May 2023 (UTC)Bumpf
:Definitely. I fixed one (it should have been ''after'' the comma), during some other edits, but was sorely tempted to remove maybe two of them to just keep the funniest one(s). Whichever that(/they) might be. I expect they'll almost all evaporate in a future edit, though, as there's plenty of editting bound to be done. [[Special:Contributions/172.70.90.219|172.70.90.219]] 19:47, 31 May 2023 (UTC)
::Nice work to whomever on that! Xkcd never fails to make me smile if not LOL, and Explainxkcd never fails to teach cool facts. o7 [[Special:Contributions/172.69.134.147|172.69.134.147]] 21:28, 31 May 2023 (UTC)

I'm pretty sure there has been serious scholarship about the habitable zone of some quasars. Let's see.... Here: https://iopscience.iop.org/article/10.1088/1742-6596/2364/1/012057/pdf Not absolutely certain, but absolutely '''not''' ruled out. [[Special:Contributions/172.69.134.24|172.69.134.24]] 20:02, 31 May 2023 (UTC)
:I think that Cueball's scientific team did a study to discount the possibilities of quasars in the habitable zone of a star, not of a habitable zone around a quasar.[[Special:Contributions/172.71.166.249|172.71.166.249]] 20:52, 31 May 2023 (UTC)
::A quasar could exist in the habitable zone of a star, and if it was particularly dim, it wouldn't make the zone inhabitable. There's no minimum brightness for quasars, is there? For example, [https://iopscience.iop.org/article/10.1088/0004-637X/728/1/26] defines quasars in terms of relative magnitude, so I don't see why a tiny black hole with a small but sufficient accretion disk in translunar orbit couldn't qualify. [[Special:Contributions/172.69.134.162|172.69.134.162]] 20:54, 31 May 2023 (UTC)
:::Relative to their ''entire galaxy!'' Fixed explanation. [[Special:Contributions/162.158.166.175|162.158.166.175]] 09:02, 1 June 2023 (UTC)

I don't know how to properly describe the length of time the Moon's orbit of the Earth has been known. If you think that the moon orbits the earth, but you also think the sun, stars, and planets orbit the earth, do you actually have any way to justifiably say that you know that the Moon orbits the Earth? Also, is it worth pointing out the reasons that the moon is such an obvious thing to know about (i.e. its visibility and prominence to the naked eye, its cultural significance,...)?[[Special:Contributions/162.158.174.183|162.158.174.183]] 20:59, 31 May 2023 (UTC)
:Interesting xkcd (sort-of) reference here. Back when What-If questions started being solicited, I sent in something (roughly) like "When trying to justify the original geocentric theory of the solar system, it is said that it had always 'looked like everything went round the Earth'... What would it have looked like if it had always looked like everything, including the Earth, went round the Sun?" ...which I'm pretty sure never got answered. Probably didn't spark enough possible scope for that good old xkcd magic. But I saw plenty of other good stuff, so no regrets on my part. [[Special:Contributions/172.70.162.251|172.70.162.251]] 23:14, 31 May 2023 (UTC)
::I think your question was particularly difficult to answer in any way other than "Everything ''does'' go around the sun. To see what that looks like, look up." I suppose your question (if I'm understanding what you may be looking for) may be stated otherwise as "How different would the movement of our Solar System need to be in order to make it obvious that everything revolves around the sun (to a layperson observer on Earth)"? [[Special:Contributions/172.70.206.194|172.70.206.194]] 14:50, 1 June 2023 (UTC)
:::I don't see much difference between the two ways of putting it (unless you think your one means seeing the 'orbital rails' upon which everything encircles things, or something).
:::Maybe, though, a fairly visible (lunar-sized) satellite of Mars/Venus might be on the edge of discernability (not needing Galileo's assisted view of the Saturnian system, just the kind of patience that raw-eyeballing astronomers used with discerning 'close' stars from each other) thus demonstrating non-geocentrism much earlier and easier and somewhat more undeniable. [[Special:Contributions/172.71.242.128|172.71.242.128]] 17:29, 1 June 2023 (UTC)
::::My proposed question was meant to clarify, so it shouldn't be much different :-) I don't know what the answer would be, but my hope was to clear up that the question wasn't simply "What would it look like if the Earth revolved around the sun?" which is what I had originally interpreted the question as before I decided that it probably wasn't the question that was meant to be asked [[Special:Contributions/172.70.210.90|172.70.210.90]] 17:40, 1 June 2023 (UTC)
:::::Maybe clunkily given here (really we need to see the original Q, not the half-recalled paraphrasing so many years after) but "in order to make it obvious that everything revolves around the [S]un" doesn't look like what you say you first read it as. So to bad writing (capital 'S'!) perhaps add bad reading, I suspect. But we're all fallible. [[Special:Contributions/172.70.91.171|172.70.91.171]] 17:57, 1 June 2023 (UTC)

Y'know, I'm not entirely convinced that "tectonically active black holes" is something that we're actually capable of ruling out [[Special:Contributions/172.68.174.190|172.68.174.190]] 22:33, 31 May 2023 (UTC)
:Even if the black hole is tectonically active, its activity is in one direction only: forward, where you can never catch up to it. The damage is extreme, but it's held safely in the boundary of the singularity. [[Special:Contributions/172.70.130.203|172.70.130.203]] 01:10, 1 June 2023 (UTC)
:I agree; black holes occupy a non-zero volume. Since the space below the event horizon has depth, I don't see any reason why the arrangement of mass inside could not shift. Indeed, the evidence of gravitational irregularities affecting their accretion discs, seems like evidence of nonhomogeneity within that volume. I think black holes probably ''do'' have "tectonic" activity!
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 16:27, 2 June 2023 (UTC)
::Counting all the volume within the event horizon (infinite, due to the infinite curvature), the density wouldn't support tectonics. The acretion disc is affected by what is on the verge of falling in (minus what has ''actually'' fallen in which just acts as a hairless 'lump'). Not sure you can call what happens in the disc as 'tectonics'... No pressures from below (the opposite) it's just interactions of decaying orbits. [[Special:Contributions/172.71.178.137|172.71.178.137]] 18:43, 2 June 2023 (UTC)

Did anyone else see the connection between this comic and the NASA briefing yesterday on UAPs (Unidentified Aerial Phenomena, their term for UFOs)? In the briefing they discussed that the approach they'd need to take is one of ruling out everything else instead of saying for certain that "this is a UAP". I think that's the entire intent of this joke - to comment on the NASA briefing. [[Special:Contributions/162.158.175.113|162.158.175.113]] 11:50, 1 June 2023 (UTC)

Strictly speaking, the first two classes of object listed couldn't be 'ruled out' by a study, since they're non-existent by definition, and therefore can't be subject to any meaningful proof or disproof.[[Special:Contributions/172.71.242.87|172.71.242.87]] 15:58, 1 June 2023 (UTC)
:While exoplanets in our solar system are non-existent by definition, ruling out earth-like stars does need some study to prove that earth is neither star nor sufficiently star-like. Note that you CAN find Jupiter-like stars. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 20:55, 1 June 2023 (UTC)
:I think part of the joke is that the "study" is just a scientist saying "Yup, that can't exist." [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 01:19, 2 June 2023 (UTC)

I think the entire point of including “habitable-zone quasars” was completely missed so far. It’s not that a quasar can’t have a habitable zone near it, even if that’s unlikely, nor is it that a quasar couldn’t be in a star’s habitable zone. It’s that SO WHAT IF IT IS? You couldn’t inhabit a quasar regardless what ‘zone’ it was in. If you were looking for a new home, you’d look at homes within a price range you could afford (not too expensive, but not TOO cheap). Looking for a quasar in the habitable zone of a star would be like asking a realtor to show you an active volcano within your price range. [[Special:Contributions/172.69.33.155|172.69.33.155]] 20:13, 1 June 2023 (UTC)
:Well ... "active volcano within my price range" is exactly what traditional Evil Overlord asks for. The smarter ones ask for volcanos which are non-active but can be made looking active. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 20:55, 1 June 2023 (UTC)
::Volcano?!? Most of us can't even afford a sinkhole. [[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 16:31, 2 June 2023 (UTC)
:::You need to up your evil overlord game, Zarquon. [[Special:Contributions/162.158.166.54|162.158.166.54]] 20:44, 2 June 2023 (UTC)
:::Afford? In Florida, many people get one for free. [[User:SDSpivey|SDSpivey]] ([[User talk:SDSpivey|talk]]) 18:43, 4 June 2023 (UTC)

Given the text at the bottom of the drawing, this also sounds like a reference to Hempel's paradox (aka raven paradox) https://en.m.wikipedia.org/wiki/Raven_paradox
[[User:Gisbert|Gisbert]] ([[User talk:Gisbert|talk]]) 21:01, 1 June 2023 (UTC)

"has to be brighter than our Sun because it's part of the containing galaxy" (edit comment) - I interpret the spec differently. This makes a quasar far more unbalancingly relative, whereby perfectly valid quasars in the next galaxy over, or further, are considered nothing of the sort for (some/most/nearly all/..?) any residents of the quasar's own galaxy who just 'happen' to be (their equivalent of) 1AU from even a very non-descript star of their own that yet easily outshines their non-quasar galactic centre (at the equivalent time, even direction, of observation). And how does that juustify multi-quasar galaxies, where the output of one may (or may not, it could result in mutual exclusion) outshine the total power of the rest of the galaxy including the other potential one(s). Yet true examples exist, that are not just false bedfellows through near-occluding asterisms. [[Special:Contributions/172.70.90.127|172.70.90.127]] 10:42, 4 June 2023 (UTC)

Just wondering. What would a rogue planet (clearly an exoplanet) that travels through our solar system be called? [[User:MDwayne|MDwayne]] ([[User talk:MDwayne|talk]]) 12:47, 4 June 2023 (UTC)
:Its page on Wikipedia is {{w|Rogue planet}}, as you named it, though I would gravitate (NPI!) towards the term Nomad. And noting that the category "Exoplanets" tends to exclude planetary-mass bodies unbound to extrasolar stars, so already really something else. (If we get better at studying them, perhaps ejected ones, i.e. "ex-exoplanets", ''might'' be brought into the fold, but any actual "failed sub-brown-dwarf" bodies were never planets to start with.)
:Such an itinerant visitor (unless it is lucky and somehow snags a gravitational reverse-slingshot to try at least a few orbits to try to become a new Solar planet; or we're unlucky enough that it collides with/deflects one or other of the current contingent and causes ourselves problems of some degree or other) would probably zoom through our system and out pretty quickly (in observational terms), and if it was happening frequentlt then the purturbations would probably be identified as aperiodic/randomly-orientated influences, so we're probably not likely to get one to even try to falsify that particular statement. Never say never but, even if you want to argue terminology, you might have to wait a while before seeing a non-solar planet do a "Bronson Beta/Zyra" (When Worlds Collide) and pass through, with or without the damage of the Bronson Alpha/Bellus partner. [[Special:Contributions/172.70.162.160|172.70.162.160]] 16:58, 4 June 2023 (UTC)

::Interesting response to my mildly sarcastic jab at part of the comic's content. I'm not sure, however, if your thesis statement about the definition of an exoplanet is set. Contradicting the claim that Wikipedia suggests a rogue planet cannot be an exoplanet, NASA suggests it is:[http://exoplanets.nasa.gov/what-is-an-exoplanet/overview/#:~:text=An%20exoplanet%20is%20any%20planet,are%20untethered%20to%20any%20star NASA Exoplanet] - in terms of this type of stuff, I give NASA an edge as a reference.
::With regards to any event that could happen, even if it is rare, still has a non-zero probability of happening. Who conceived we would witness Oumuamua? How much bigger would it have to be to be a planet? So, in the spirit of the topic, maybe it '''COULD''' be a legitimate area of study.[[User:MDwayne|MDwayne.ca]] ([[User talk:MDwayne|talk]]) 18:52, 4 June 2023 (UTC)

Talk:2783: Ruling Out

2023-06-04T12:47:14Z

MDwayne: Solar system exoplanet

Wow. the amount of citation needed tags is excessive. Here's a fun idea, do like that SMBC comic and actually find and give citations. [[Special:Contributions/172.69.70.72|172.69.70.72]] 19:41, 31 May 2023 (UTC)Bumpf
:Definitely. I fixed one (it should have been ''after'' the comma), during some other edits, but was sorely tempted to remove maybe two of them to just keep the funniest one(s). Whichever that(/they) might be. I expect they'll almost all evaporate in a future edit, though, as there's plenty of editting bound to be done. [[Special:Contributions/172.70.90.219|172.70.90.219]] 19:47, 31 May 2023 (UTC)
::Nice work to whomever on that! Xkcd never fails to make me smile if not LOL, and Explainxkcd never fails to teach cool facts. o7 [[Special:Contributions/172.69.134.147|172.69.134.147]] 21:28, 31 May 2023 (UTC)

I'm pretty sure there has been serious scholarship about the habitable zone of some quasars. Let's see.... Here: https://iopscience.iop.org/article/10.1088/1742-6596/2364/1/012057/pdf Not absolutely certain, but absolutely '''not''' ruled out. [[Special:Contributions/172.69.134.24|172.69.134.24]] 20:02, 31 May 2023 (UTC)
:I think that Cueball's scientific team did a study to discount the possibilities of quasars in the habitable zone of a star, not of a habitable zone around a quasar.[[Special:Contributions/172.71.166.249|172.71.166.249]] 20:52, 31 May 2023 (UTC)
::A quasar could exist in the habitable zone of a star, and if it was particularly dim, it wouldn't make the zone inhabitable. There's no minimum brightness for quasars, is there? For example, [https://iopscience.iop.org/article/10.1088/0004-637X/728/1/26] defines quasars in terms of relative magnitude, so I don't see why a tiny black hole with a small but sufficient accretion disk in translunar orbit couldn't qualify. [[Special:Contributions/172.69.134.162|172.69.134.162]] 20:54, 31 May 2023 (UTC)
:::Relative to their ''entire galaxy!'' Fixed explanation. [[Special:Contributions/162.158.166.175|162.158.166.175]] 09:02, 1 June 2023 (UTC)

I don't know how to properly describe the length of time the Moon's orbit of the Earth has been known. If you think that the moon orbits the earth, but you also think the sun, stars, and planets orbit the earth, do you actually have any way to justifiably say that you know that the Moon orbits the Earth? Also, is it worth pointing out the reasons that the moon is such an obvious thing to know about (i.e. its visibility and prominence to the naked eye, its cultural significance,...)?[[Special:Contributions/162.158.174.183|162.158.174.183]] 20:59, 31 May 2023 (UTC)
:Interesting xkcd (sort-of) reference here. Back when What-If questions started being solicited, I sent in something (roughly) like "When trying to justify the original geocentric theory of the solar system, it is said that it had always 'looked like everything went round the Earth'... What would it have looked like if it had always looked like everything, including the Earth, went round the Sun?" ...which I'm pretty sure never got answered. Probably didn't spark enough possible scope for that good old xkcd magic. But I saw plenty of other good stuff, so no regrets on my part. [[Special:Contributions/172.70.162.251|172.70.162.251]] 23:14, 31 May 2023 (UTC)
::I think your question was particularly difficult to answer in any way other than "Everything ''does'' go around the sun. To see what that looks like, look up." I suppose your question (if I'm understanding what you may be looking for) may be stated otherwise as "How different would the movement of our Solar System need to be in order to make it obvious that everything revolves around the sun (to a layperson observer on Earth)"? [[Special:Contributions/172.70.206.194|172.70.206.194]] 14:50, 1 June 2023 (UTC)
:::I don't see much difference between the two ways of putting it (unless you think your one means seeing the 'orbital rails' upon which everything encircles things, or something).
:::Maybe, though, a fairly visible (lunar-sized) satellite of Mars/Venus might be on the edge of discernability (not needing Galileo's assisted view of the Saturnian system, just the kind of patience that raw-eyeballing astronomers used with discerning 'close' stars from each other) thus demonstrating non-geocentrism much earlier and easier and somewhat more undeniable. [[Special:Contributions/172.71.242.128|172.71.242.128]] 17:29, 1 June 2023 (UTC)
::::My proposed question was meant to clarify, so it shouldn't be much different :-) I don't know what the answer would be, but my hope was to clear up that the question wasn't simply "What would it look like if the Earth revolved around the sun?" which is what I had originally interpreted the question as before I decided that it probably wasn't the question that was meant to be asked [[Special:Contributions/172.70.210.90|172.70.210.90]] 17:40, 1 June 2023 (UTC)
:::::Maybe clunkily given here (really we need to see the original Q, not the half-recalled paraphrasing so many years after) but "in order to make it obvious that everything revolves around the [S]un" doesn't look like what you say you first read it as. So to bad writing (capital 'S'!) perhaps add bad reading, I suspect. But we're all fallible. [[Special:Contributions/172.70.91.171|172.70.91.171]] 17:57, 1 June 2023 (UTC)

Y'know, I'm not entirely convinced that "tectonically active black holes" is something that we're actually capable of ruling out [[Special:Contributions/172.68.174.190|172.68.174.190]] 22:33, 31 May 2023 (UTC)
:Even if the black hole is tectonically active, its activity is in one direction only: forward, where you can never catch up to it. The damage is extreme, but it's held safely in the boundary of the singularity. [[Special:Contributions/172.70.130.203|172.70.130.203]] 01:10, 1 June 2023 (UTC)
:I agree; black holes occupy a non-zero volume. Since the space below the event horizon has depth, I don't see any reason why the arrangement of mass inside could not shift. Indeed, the evidence of gravitational irregularities affecting their accretion discs, seems like evidence of nonhomogeneity within that volume. I think black holes probably ''do'' have "tectonic" activity!
:[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 16:27, 2 June 2023 (UTC)
::Counting all the volume within the event horizon (infinite, due to the infinite curvature), the density wouldn't support tectonics. The acretion disc is affected by what is on the verge of falling in (minus what has ''actually'' fallen in which just acts as a hairless 'lump'). Not sure you can call what happens in the disc as 'tectonics'... No pressures from below (the opposite) it's just interactions of decaying orbits. [[Special:Contributions/172.71.178.137|172.71.178.137]] 18:43, 2 June 2023 (UTC)

Did anyone else see the connection between this comic and the NASA briefing yesterday on UAPs (Unidentified Aerial Phenomena, their term for UFOs)? In the briefing they discussed that the approach they'd need to take is one of ruling out everything else instead of saying for certain that "this is a UAP". I think that's the entire intent of this joke - to comment on the NASA briefing. [[Special:Contributions/162.158.175.113|162.158.175.113]] 11:50, 1 June 2023 (UTC)

Strictly speaking, the first two classes of object listed couldn't be 'ruled out' by a study, since they're non-existent by definition, and therefore can't be subject to any meaningful proof or disproof.[[Special:Contributions/172.71.242.87|172.71.242.87]] 15:58, 1 June 2023 (UTC)
:While exoplanets in our solar system are non-existent by definition, ruling out earth-like stars does need some study to prove that earth is neither star nor sufficiently star-like. Note that you CAN find Jupiter-like stars. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 20:55, 1 June 2023 (UTC)
:I think part of the joke is that the "study" is just a scientist saying "Yup, that can't exist." [[User:Barmar|Barmar]] ([[User talk:Barmar|talk]]) 01:19, 2 June 2023 (UTC)

I think the entire point of including “habitable-zone quasars” was completely missed so far. It’s not that a quasar can’t have a habitable zone near it, even if that’s unlikely, nor is it that a quasar couldn’t be in a star’s habitable zone. It’s that SO WHAT IF IT IS? You couldn’t inhabit a quasar regardless what ‘zone’ it was in. If you were looking for a new home, you’d look at homes within a price range you could afford (not too expensive, but not TOO cheap). Looking for a quasar in the habitable zone of a star would be like asking a realtor to show you an active volcano within your price range. [[Special:Contributions/172.69.33.155|172.69.33.155]] 20:13, 1 June 2023 (UTC)
:Well ... "active volcano within my price range" is exactly what traditional Evil Overlord asks for. The smarter ones ask for volcanos which are non-active but can be made looking active. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 20:55, 1 June 2023 (UTC)
::Volcano?!? Most of us can't even afford a sinkhole.
::[[User:ProphetZarquon|ProphetZarquon]] ([[User talk:ProphetZarquon|talk]]) 16:31, 2 June 2023 (UTC)
:::You need to up your evil overlord game, Zarquon. [[Special:Contributions/162.158.166.54|162.158.166.54]] 20:44, 2 June 2023 (UTC)

Given the text at the bottom of the drawing, this also sounds like a reference to Hempel's paradox (aka raven paradox) https://en.m.wikipedia.org/wiki/Raven_paradox
[[User:Gisbert|Gisbert]] ([[User talk:Gisbert|talk]]) 21:01, 1 June 2023 (UTC)

"has to be brighter than our Sun because it's part of the containing galaxy" (edit comment) - I interpret the spec differently. This makes a quasar far more unbalancingly relative, whereby perfectly valid quasars in the next galaxy over, or further, are considered nothing of the sort for (some/most/nearly all/..?) any residents of the quasar's own galaxy who just 'happen' to be (their equivalent of) 1AU from even a very non-descript star of their own that yet easily outshines their non-quasar galactic centre (at the equivalent time, even direction, of observation). And how does that juustify multi-quasar galaxies, where the output of one may (or may not, it could result in mutual exclusion) outshine the total power of the rest of the galaxy including the other potential one(s). Yet true examples exist, that are not just false bedfellows through near-occluding asterisms. [[Special:Contributions/172.70.90.127|172.70.90.127]] 10:42, 4 June 2023 (UTC)

Just wondering. What would a rogue planet (clearly an exoplanet) that travels through our solar system be called? [[User:MDwayne|MDwayne]] ([[User talk:MDwayne|talk]]) 12:47, 4 June 2023 (UTC)

User:NerillDP

2021-05-23T14:40:01Z

MDwayne:

Just some guy.

You know him.

He's that guy that did that thing.

Many people witnessed it, but nobody talks about it now.

contact: [nerill.dp@gmail.com]