1300: "Galilean Moons"

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Actaeus
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1300: "Galilean Moons"

Postby Actaeus » Fri Dec 06, 2013 5:12 am UTC

Image

Title text: I'm SO glad I escaped. They almost had me caught in their weird ... thing.

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Re: 1300: "Galilean Moons"

Postby rhomboidal » Fri Dec 06, 2013 5:13 am UTC

Galilean moons are like astronomical crabs.

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Actaeus
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Re: 1300: "Galilean Moons"

Postby Actaeus » Fri Dec 06, 2013 5:16 am UTC

Indeed.

Worth noting: This comic is slightly inaccurate, as the three moons never line up simultaneously. Ganymede is always 90 degrees out of phase (ahead or behind) when Io and Europa align.

In other words:
"Hi!"
"Hi!" "What's your name?"
"H--" "MOOOOON"
"Hi!" "What's your name?"
"Hi!"
"Hi!" "What's your name?"
"H--" "MOOOOON"
"Hi!" "What's your name?"
"Hi!"
"Hi!" "What's your name?"
"H--" "MOOOOON"
"Hi!" "What's your name?"
"Hi!"
"Hi!" "What's your name?"
"H--" "MOOOOON"
"Hi!" "What's your name?"

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StClair
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Re: 1300: "Galilean Moons"

Postby StClair » Fri Dec 06, 2013 5:18 am UTC

ah, orbital resonance.

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Re: 1300: "Galilean Moons"

Postby Pfhorrest » Fri Dec 06, 2013 6:54 am UTC

Ok, I totally don't get this one. I know that Galilean moons have an orbital resonance but I don't understand what's with asking names and why is one moon just shouting "MOOOOOOON!"? And... does one of the moons go off to orbit the other planet-person at the end? Is that supposed to happen eventually? That still doesn't explain the dialogue...
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Re: 1300: "Galilean Moons"

Postby CorruptUser » Fri Dec 06, 2013 7:08 am UTC

That's Ganymede. It's the largest of the moons. I guess, umm, it's a stupid moon that blocks the other moons?

Callisto is the only one that isn't part of the orbital resonance, I guess. Because resonance is too trendy or something.

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Re: 1300: "Galilean Moons"

Postby Copper Bezel » Fri Dec 06, 2013 7:29 am UTC

It's a weak pun on the term resonance. The moons in resonance are singing a round. Callisto is happy to be captured before it gets drawn into a resonance and has to join the inane chorus.
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Re: 1300: "Galilean Moons"

Postby nahtanoj999 » Fri Dec 06, 2013 7:48 am UTC

Randall forgot the joke again.

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Re: 1300: "Galilean Moons"

Postby keithl » Fri Dec 06, 2013 7:56 am UTC

Pfhorrest wrote:... does one of the moons go off to orbit the other planet-person at the end? Is that supposed to happen eventually?


Interesting suggestion. Callisto's orbital period is 400 hours, the Jupiter day is 10 hours, and Jupiter is far more fluid than Earth. This implies that Callisto is picking up angular momentum from Jupiter via tidal forces, with little slowing of Jupiter's spin. So, Callisto is getting pushed outwards in its orbit faster than the Moon is pushed outwards from Earth. In time, Callisto may escape Jupiter, though I haven't a clue how long that will take. Perhaps the implication of the comic is that Callisto will someday be captured by Saturn. Jupiter pushes most of the planets around; current thinking is that Saturn, Uranus, and Neptune originally orbited closer in, and that Jupiter is pushing them further out (see Near-Earth Objects by Donald Yeomans, currently on the nightstand).

I couldn't find a reference for Callisto escape and Saturn capture using Google Scholar or arxiv.org, the usual suspects. I may not know where to look, or perhaps this is a preview of a forthcoming paper by one of Randall Munroe's planetary astronomer buddies.

Interesting to speculate about; is anyone here able to do the tidal coupling math and estimate the escape rate? If this is NOT in the literature, and the math works out, perhaps WE could write the paper, and credit XKCD as a reference.
Last edited by keithl on Fri Dec 06, 2013 4:14 pm UTC, edited 3 times in total.

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Copper Bezel
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Re: 1300: "Galilean Moons"

Postby Copper Bezel » Fri Dec 06, 2013 8:16 am UTC

The comic would have been much simpler to follow if the moons had something else to distinguish them than size - perhaps color coding? = )
So much depends upon a red wheel barrow (>= XXII) but it is not going to be installed.

she / her / her

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Re: 1300: "Galilean Moons"

Postby obarey » Fri Dec 06, 2013 8:52 am UTC

rhomboidal wrote:Galilean moons are like astronomical crabs.

Not the only ones: http://pbfcomics.com/248/

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Re: 1300: "Galilean Moons"

Postby Klear » Fri Dec 06, 2013 10:08 am UTC

Copper Bezel wrote:It's a weak pun on the term resonance. The moons in resonance are singing a round. Callisto is happy to be captured before it gets drawn into a resonance and has to join the inane chorus.


Singing? What are they singing? I'm also completely lost.

Edit: explainxkcd didn't help much, but this gif is pretty neat:

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Re: 1300: "Galilean Moons"

Postby Eutychus » Fri Dec 06, 2013 10:19 am UTC

Klear wrote:Singing? What are they singing? I'm also completely lost.


I'm completely lost too, but as I scrolled down the thread I thought I had a bug on my monitor. Then it turned out to be your gif. That is all I have to say on this subject.
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Re: 1300: "Galilean Moons"

Postby jennyxyzzy » Fri Dec 06, 2013 10:50 am UTC

It would have been funnier if the title was "Harlem Shake"...

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Re: 1300: "Galilean Moons"

Postby Klear » Fri Dec 06, 2013 10:54 am UTC

Eutychus wrote:
Klear wrote:Singing? What are they singing? I'm also completely lost.


I'm completely lost too, but as I scrolled down the thread I thought I had a bug on my monitor. Then it turned out to be your gif. That is all I have to say on this subject.


It's not a bug, it's a feature!

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Re: 1300: "Galilean Moons"

Postby dtilque » Fri Dec 06, 2013 11:11 am UTC

Io always says "HI", Europa always says "What's your name?", and Ganymede always says "Moooooon!" Any reason why these particular vocalizations?

BTW, Calisto was right to escape. Those guys are creepy. Or else they're toddlers going through the stage of repeating the same things over and over.
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Re: 1300: "Galilean Moons"

Postby PhDFluff » Fri Dec 06, 2013 12:14 pm UTC

I just spent several minutes looking at Klear's gif saying this over and over:

Hi!
What'syournameHi!
Hi!
What'syournameHi MOOOOOOON!

Hi!
What'syournameHi!
Hi!
What'syournameHi MOOOOOOON!

It was a fun five minutes

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Re: 1300: "Galilean Moons"

Postby Carteeg_Struve » Fri Dec 06, 2013 12:34 pm UTC

Io: "Hi!"
Io: "Hi!" Europa: "What's your name?"
Io: "Hi!"
Io: "Hi!" Europa: "What's your-?" Ganymede: "MOOOOON!"
Io: "Hi!"
Io: "Hi!" Europa: "What's your name?"
Io: "Hi!"
Io: "Hi!" Europa: "What's your-?" Ganymede: "M-!" Cassini-Huygens: "SPAAAAAAAAAAAAAAAAAAAAAAAACE!!!!!"
Io, Europa, Ganymede: O_o

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Re: 1300: "Galilean Moons"

Postby Quicksilver » Fri Dec 06, 2013 12:46 pm UTC

Galileo Was Alone. Wow. A weird first thought to have. Galileo decided to start listing his observations, for posterity.

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Re: 1300: "Galilean Moons"

Postby Shidoshi » Fri Dec 06, 2013 12:50 pm UTC

Well, obviously the three orbiting objects are talking to the girl each time they pass in front of her. The closer, faster one says "Hi!" each time it passes in an agitated ADHD-way; the second one says "What's your name?" while going at a more normal rate; finally, the slowest one says in a droll voice "MOOOOOOOOON!".

The last one doesn't identify with these cyclic dialogues and is annoyed by them.

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Re: 1300: "Galilean Moons"

Postby Klear » Fri Dec 06, 2013 12:53 pm UTC

Shidoshi wrote:Well, obviously the three orbiting objects are talking to the girl each time they pass in front of her. The closer, faster one says "Hi!" each time it passes in an agitated ADHD-way; the second one says "What's your name?" while going at a more normal rate; finally, the slowest one says in a droll voice "MOOOOOOOOON!".

The last one doesn't identify with these cyclic dialogues and is annoyed by them.


So it's something a bit like this?

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Re: 1300: "Galilean Moons"

Postby orthogon » Fri Dec 06, 2013 1:05 pm UTC

Klear wrote:
Shidoshi wrote:Well, obviously the three orbiting objects are talking to the girl each time they pass in front of her. The closer, faster one says "Hi!" each time it passes in an agitated ADHD-way; the second one says "What's your name?" while going at a more normal rate; finally, the slowest one says in a droll voice "MOOOOOOOOON!".

The last one doesn't identify with these cyclic dialogues and is annoyed by them.


So it's something a bit like this?

Hmm, might have made more sense if they were playing some variant of fizz, wizz, bang. (By the way, what exactly is happening in anjurdsg's avatar?)
xtifr wrote:... and orthogon merely sounds undecided.

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Re: 1300: "Galilean Moons"

Postby Klear » Fri Dec 06, 2013 1:21 pm UTC

orthogon wrote:(By the way, what exactly is happening in anjurdsg's avatar?)


(Who is that?)
((Oh! In the link... err... I'm not going to answer that))

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Re: 1300: "Galilean Moons"

Postby J L » Fri Dec 06, 2013 1:25 pm UTC

Pfhorrest wrote:I know that Galilean moons have an orbital resonance but I don't understand what's with asking names and why is one moon just shouting "MOOOOOOON!"?

Klear wrote:Singing? What are they singing? I'm also completely lost.

I think it's just nonsense. Maybe the moons aren't that "bright" after all and behave something like goldfishes ("Oh, a pane! Again!") Ganymede "moons" in capital letters because of the "resonance", i.e. like a feedback loop. Callisto is just annoyed (of being an outsider to their cyclic game or by the others and their "thing" in general.

I must say I liked this one very much. The idea of "having moons" is just hilariously bizarre, and I think the comic even gets better with time. I also found http://www.explainxkcd.com/wiki/index.php?title=1300 to be helpful, especially in suggesting that Io, Europa and Ganymede all had some "weird" sexual thing going on with Zeus.

Copper Bezel wrote:The comic would have been much simpler to follow if the moons had something else to distinguish them than size - perhaps color coding? = )

Well, Callisto has craters, and Ganymede is the big one. I think it's enough to follow their orbits from panel to panel.

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Re: 1300: "Galilean Moons"

Postby cellocgw » Fri Dec 06, 2013 2:04 pm UTC

Ok, so she's got a case of the Galilean Moons.

Is it curable? Is it contagious? Is it street-legal?
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Re: 1300: "Galilean Moons"

Postby keithl » Fri Dec 06, 2013 4:01 pm UTC

cellocgw wrote:Ok, so she's got a case of the Galilean Moons. Is it curable? Is it contagious? Is it street-legal?

Did she get it from Agnes?

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Re: 1300: "Galilean Moons"

Postby rainspeaker » Fri Dec 06, 2013 6:14 pm UTC

Some of Randall's jokes are sort of rigid puns or plays on geeky concepts. Frequently they're very good ones, but still.
But once in a while he comes out with something that's just delightfully absurd and that sparks your imagination, eg. http://xkcd.com/1031/ or http://xkcd.com/886/. This is one of those!

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Re: 1300: "Galilean Moons"

Postby Rendon » Fri Dec 06, 2013 6:16 pm UTC

I was thinking the third moon might be referencing DBZ Abridged

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Re: 1300: "Galilean Moons"

Postby Phasma Felis » Fri Dec 06, 2013 7:04 pm UTC

Ganymede might possibly be a Wondermark reference.

Image

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Re: 1300: "Galilean Moons"

Postby JohnTheWysard » Fri Dec 06, 2013 7:14 pm UTC

Well, that's a bit risque... she mooned him!

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Re: 1300: "Galilean Moons"

Postby chridd » Fri Dec 06, 2013 7:17 pm UTC

orthogon wrote:Hmm, might have made more sense if they were playing some variant of fizz, wizz, bang. (By the way, what exactly is happening in anjurdsg's avatar?)
It looks like Mario has beaten up Peach and is now stealing 1-up mushrooms from her pocket.
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Re: 1300: "Galilean Moons"

Postby mattholimeau » Fri Dec 06, 2013 7:39 pm UTC

The idea of "having moons" reminds me of the Xanth series of books. A quick google informs me that the character who had moons was Ida. I miss being young enough to be able to stomach all the puns in those novels, hah.

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Re: 1300: "Galilean Moons"

Postby StCredZero » Fri Dec 06, 2013 8:43 pm UTC


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Re: 1300: "Galilean Moons"

Postby Annihilist » Mon Dec 09, 2013 1:47 am UTC

I didn't get this at first, but I researched orbital resonance and came to the conclusion that this is hilarious.

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Re: 1300: "Galilean Moons"

Postby ysth » Mon Dec 09, 2013 3:30 am UTC

For no particular reason, I started reading the comic and the characters mysteriously morphed into d8z and f8d.

I think I like it better that way.
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