2809: Moon

Explain xkcd: It's 'cause you're dumb.
Revision as of 02:09, 12 September 2023 by 172.70.207.38 (talk) (Explanation: ce)
Jump to: navigation, search
Moon
I mean, it's pretty, but it doesn't really affect us beyond that. Except that half the nights aren't really dark, and once or twice a day it makes the oceans flood the coasts.
Title text: I mean, it's pretty, but it doesn't really affect us beyond that. Except that half the nights aren't really dark, and once or twice a day it makes the oceans flood the coasts.

Explanation

The Moon is a celestial body orbiting Earth, first formed approximately 4.5 billion years ago - about 50 million years after the initial formation of the solar system. As of the date of this comic, the Moon is still orbiting the Earth[citation needed] at a distance of approximately 384,400 kilometers, or about 238,900 miles.

This comic points out how weird it is to have such an enormous celestial body near to us. The Moon has a radius more than one quarter of Earth's, and is around one eightieth of Earth's mass, and is so close that major surface features are visible, even with the naked eye, and much more clearly visible with even a simple telescope. Celestial distances tend to be so large that only truly immense objects can be seen without magnification, and even those tend to appear only as points of light to the naked eye. The second nearest body of notable size, Venus, is approximately 46.576 million kilometers away at its closest. The fact that there's "another world" that's close enough that humanity has always been aware of it, but distant enough that it couldn't be reached until a space program was developed, is a striking feature of Earth that we take for granted, only because it's always been that way.

While it's not uncommon for planets to have orbiting moons, no other planet in the solar system has a moon that's so large, in relation to the planet. Of the other rocky planets, only Mars has moons, and the largest of those is only 14 miles across.

Pluto and Charon are closer in size, than even the Earth/Moon system, but this meant that they had actually become seriously considered as a double(/binary) planet pair, had not Pluto been redesignated as a "dwarf planet". There is the possibility a term such as "double dwarf planet" could be adopted, at some point, as "double minor planet" is sometimes already used for binary asteroid systems. The lesser bodies of the Pluto-Charon system may then even be considered as circumbinary moons.

Other than this, Earth is the only accepted planet we're currently aware of that has a satellite that's so visible from its surface.

The title text sarcastically claims that, other than being "pretty", the Moon doesn't impact us, then subverts it by mentioning substantial impacts it has on Earth. Having such a large satellite so close has impacts that we take for granted only because we're used to them, but if they hadn't always existed, they'd seem unbelievable. One is that, for half the lunar cycle, the moon reflects enough light to produce visibility at night. The other impact is tides, since the gravitational pull of the Moon is large enough to alter the surfaces of oceans, causing shorelines to shift on a daily cycle. The text mentions these dismissively, in a deliberate contrast with their huge significance. Moonlight alters the illumination cycle of the planet to a significant degree, which changes how both humans and other animals operate at night, even before the advent of artificial lighting. Tides had major impacts on the development of life, continue to affect ecosystems, and play an essential role in our ability to interact with the oceans. If someone from a planet without such a large moon were to observe these impacts, they'd likely be shocked and amazed by them, but we barely notice them.

Transcript

[Ponytail is pointing and looking up to the left, while Cueball behind her looks the same way.]
Ponytail: That thing hanging in the sky is a second nearby world. It's close enough that you can see its surface as it passes overhead.
Cueball: Wow. Isn't that ... weird?
Ponytail: I dunno, it's just always been there.
[Caption below the panel:]
If it didn't exist, the moon would sound like such an outlandish sci-fi concept.

Trivia

  • Earth's moon can be considered weird for additional reasons.
    • It is by far the largest and most massive moon relative to the planet it orbits.
    • Our moon is the only moon in the solar system to not have a proper name, not even a jumble of letters and numbers. In English it is simply given the proper name of "the Moon" (capitalized), being the ancient archetype for all other moons discovered since the time of Galileo, although it can also be described by other titles such as "Luna" (directly taken from from Latin mythology/astronomy).
    • It is almost exactly the same apparent size as the Sun in the sky which at various times enables both total solar eclipses (for which it needs to be close/large) and annular ones (for which it must not be too close/large). Much earlier in history it was too close to do both and much later it will gradually drift too far away to do so – making it additionally a temporal coincidence that humanity gets to witness it as we are so used to seeing it.
    • There are even a couple of hypotheses that think that to get protein shaped right for life, the tides were needed, and that to evolve for living on land the tides are needed.
comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!

Discussion

Happy birthday to me. This comic is a good birthday present, so I'm gonna try to add some stuff to the explanation now. R3TRI8UTI0N (talk) 02:11, 1 August 2023 (UTC)

Okay, added a Trivia section and a lot of stuff to the explanation. Request someone help add more information about lunar cycles and some wikipedia links. R3TRI8UTI0N (talk) 02:35, 1 August 2023 (UTC)

Ah, well, I added more (sufficient? ...haven't wikilinked yet) info about the illumination/tide cycles. i.e. about half the time (at least) half reilluminating areas on the night side of Earth + roughly twice a day dragging/flinging the tides 'upwards' (modifying the Sun's own twice-daily effects).
Had to heavily qualify the secondary Trivia point, for caveats. I mean selenically-specific names aren't rare, when refering to orb sometimes known as Phoebe/Cynthia, until you become more precise about "common English use". Didn't say anything about (the) Earth, but did mention the Sun(/suns in general) in the edit comment. Interesting point to make, but not so much unusual as stemming from long time (way into prehistory!) custom so really being the heavily weighted precedent. 172.70.90.187 05:21, 1 August 2023 (UTC)
...what? I don't understand. R3TRI8UTI0N (talk) 05:32, 2 August 2023 (UTC)
"it can also be described by other titles such as "Luna" (directly taken from from Latin mythology/astronomy)." It's not true that "the Moon doesn't have a name". It is the Moon (unlike other moons), plus all kinds of other names (historical, other culture and/or other language; such as Chandra/Igaluk/Chang'e). But it is interesting to note that, until we were able to imagine (and/or see) moons orbiting other things up in the sky, there was just its proper name. Whatever it might be. Only after we anticipated the existence of satellites of other planets (and, perhaps, other satellites of our own planet), having first recognised what other planets actually were (distinct from stars, with those being other suns than our Sun/Sol/Ra/...) was it meaningful that the name(s) we did use for it might be re-used to describe the class of things that were like it. But they then really needed their own fresh names/catalogue numbers. 172.71.242.15 10:11, 2 August 2023 (UTC)
Reminds me of that conversation from Dragonheart (paraphrized as I only watched the German dub): "So instead of calling me 'dragon" in your language you call me 'dragon' in another language... I think I like it" Elektrizikekswerk (talk) 07:16, 1 August 2023 (UTC)

If there was no Moon, would an Earth astronomer that discovered moons around one of the other planets be considered a loony? These Are Not The Comments You Are Looking For (talk) 02:40, 1 August 2023 (UTC)

If there was no moon, it's quite possible there would be no intelligent life on Earth. Also, when Galileo Galilei found Jupiter's moons, he was totally considered loony by some, while others said it's defect of the telescope. Remember that at that point of history, suggesting that if Earth has moon, other planets might have one too was something you could be burned on stake for. -- Hkmaly (talk) 03:13, 1 August 2023 (UTC)
Definitely not. (I see what you did there.) --172.70.247.155 12:55, 1 August 2023 (UTC)

I doubt the title text is intended as a reference to that saying. 172.69.247.51 04:17, 1 August 2023 (UTC)

Yeah, I don't get how that is related either. The title text references that it is pretty, but the nmoves away from that. Not sure how that is related to a quote that doesn't even use the word "pretty". --Lupo (talk) 09:28, 1 August 2023 (UTC)
I mean, the word "beautiful" and "pretty" have common meanings, so I thought about that connection, but if no one else made the connection, so be it. R3TRI8UTI0N (talk) 05:30, 2 August 2023 (UTC)
I think if that connection was meant to be invoked it would just say beautiful, or get more into detail of the way it is pretty/beautiful. However it was just used as a kind of connector to make the other mentioned aspects seem more minor. --Lupo (talk) 08:05, 2 August 2023 (UTC)

Like many things,[citation needed] it has probably seemed usual whilst we only know our own example. Once we started to find other examples out there, we can discover the ways in which it's an outlier. (Martian: "Well of course there's those two small rock 'stars' visibly zipping around overhead, that's what the sky alsays looks like for me, and I imagine that it's much the same for anyone else..." Earthling/Venusian/Jovian/Tritonian/Plutoid: "...hold my beer!") 141.101.99.133 07:26, 1 August 2023 (UTC)

I've been saying this about the Sun… A great fireball looming in the sky. It remotely powers life. (Even with 90% of that power lost at each trophic level!) It is worshipped as a god. It controls Earthlings' sense of time. When it leaves the sky at a regular interval, a wave of fear follows, and everything seeks shelter and goes dormant until its return. Oh, but it also burns and mutates the flesh of those who stand in its rays, to the point that it's dangerous to look at. Sounds fake, right? And yet, there it is. ~AgentMuffin 08:00, 1 August 2023 (UTC)

I have a personal theory that the constant gravitational massage is responsible for sustaining the Earth's large magnetic field, thus preventing the solar wind making us like Venus or Mars, and probably keeping the tectonic plates on the move. (Oh and dogs domesticated themselves - just saying p.s. same for cats but only after we had barns). RIIW - Ponder it (talk) 09:38, 1 August 2023 (UTC)

I think we’re well past the point of “plans being made” of humans returning to the Moon. Silver (talk) 19:29, 1 August 2023 (UTC)

You mean that we are currently building rockets and stuff to send people to the moon at this very moment? R3TRI8UTI0N (talk) 05:32, 2 August 2023 (UTC)
We are. Which I hope you're aware of. But if you weren't... this your lucky day! 172.71.242.15 10:11, 2 August 2023 (UTC)
Huh. I thought we were still only in the planning phase. Admittedly, paying attention to the news these days tends to be bad for one's mental health, all things considered. R3TRI8UTI0N (talk) 03:19, 9 August 2023 (UTC)
Space Launch System and Artemis 1 built and launched with further SLSs and Artemises(/Artemii?/Artemoxen?) being built for the followup missions. The bit of the mission with SpaceX Starship has been built/tested over variously incremental degrees, but is still far short of even Artemis's trans-lunar test as far as proving itself capable. But there is definitely more than just plans. (Though wouldn't be surprised if there are also contingency plans, if MusX gets too distracted and cannot actually deliver his element contribution. Like shuffling the Bezos version up the order, though that's also far (indeed, further) from usability right now.)
Artemis 2 doesn't depend upon anything additional (manufacturing aside) and so the trans-/circum-lunar manned mission is likely to happen (eventually) unless actively cancelled/reconfigured, for possibly political reasons (the current schedule of November 2024 is potentially between the election and inaugoration/continuation of the next/incumbant/returning US President, so any slipping NASA schedules and sudden changes in direction from 'above' are possibly going to interact), even with current equipment already partly in existence. Artemis 3's landing mission is far more hypothetical, right now, but predominantly for all the various non-NASA reasons (e.g. politics and, possibly, the fallout of any further Twitter/X 'developments' that have knock-on-effects that hinder/do not help SpaceX to solve its own entirely different problems). Assuming '2' itself isn't a practical(/fatal) failure in its own right, of course.
But this is just my own (broad) thinking about what pieces are in place or in the process of being placed. There are both professionals and supra-amateurs who keep a very close eye on all these things and might be far more informed about current progress. Yet I think I'm safe to roughly update you on the current "beyond planning" status of the Artemis programme, giving you various interesting advances and caveats that you were not aware of. ...watch this space? (Or space in general!) 172.71.242.15 10:14, 9 August 2023 (UTC)

August 1, 2023 the moon is a "Super Moon" KingPenguin (talk) 22:13, 1 August 2023 (UTC)

We need to make a category for these things which would sound outlandish if they didn't exist. 2115 is the first one I think of, and I'm sure there's more. I propose we call it Category: Things That Seem Like They Shouldn't Work But Do in honor of 2540. Take The A Train To Watertown (talk) 12:20, 2 August 2023 (UTC)

2085 title text. --Lupo (talk) 05:01, 3 August 2023 (UTC)

@84596Gamma - yes, really. (But not as much as a spoon.) 172.71.178.186 15:00, 2 August 2023 (UTC)

I'm kind of surprised no one has mentioned The Broken Earth Trilogy by N. K. Jemisin yet. Stickfigurefan (talk) 16:25, 17 August 2023 (UTC)