xkcd #2908: Moon Armor Index : xkcd

[–] [email protected] 89 points 7 months ago* (last edited 7 months ago) (3 children)

One of my all-time favourite facts is that solar eclipses are actually a very rare thing to happen in space. There is no reason why but our moon just happens to be the right size/distance to have this happen.

I've never seen one in person, but the next one is on the 8th of April crossing Mexico and the US. If you have the chance and are able, go check it out, if only to gloat on an internet stranger longing for his first total eclipse.

[–] [email protected] 17 points 7 months ago (2 children)

Saw one when I was 9 like 20 years ago. Still one of the coolest things I've ever seen. Definitely worth a trip if you can.

[–] [email protected] 13 points 7 months ago (1 children)

And keep in mind that the difference between a total eclipse and a partial eclipse is massive. It's worth it to find a spot that is in the line of totality.

[–] [email protected] 7 points 7 months ago (1 children)

Yep, total eclipse is metal as fuck

[–] [email protected] 5 points 7 months ago

I got to see one about 7 years ago. Made a whole vacation of it, and was not disappointed. In the darkness, all the birds stopped singing. And to top it off, at the motel I stayed there was a cleaning lady yelling at me to get back into my room because this was a sign from her god saying this was the end of days.

[–] [email protected] 7 points 7 months ago (1 children)

One passed over my area while I was at university, and the professor whose class we were meant to be in just said the day beforehand that he wasn't even going to bother scheduling anything for the first hour because he didn't expect anyone to be in. There's a famous hill-top cemetery in the city, and sure enough I saw basically all of my classmates there too

[–] [email protected] 3 points 7 months ago (1 children)

There’s a famous hill-top cemetery in the city, and sure enough I saw basically all of my classmates there too

That was an unexpected dark turn. Glad you live to tell their story!

[–] [email protected] 3 points 7 months ago

Strange things happen under an eclipse, and strangest of them all was a class full of undead attending lectures

[–] [email protected] 10 points 7 months ago (1 children)

As Moon is slowly moving away, at some point in the future there will be no more full eclipse. And there is 2 full eclipse by year !

[–] [email protected] -5 points 7 months ago (2 children)

Nah, it's just a moving away, then moving closer again thing over millions of years. Balance between gravity and centrifugal force.

[–] [email protected] 9 points 7 months ago

This is incorrect. The moon is moving away from the earth and will stop. At some point in the future the tidal forces will balance out and the earth-luna system will be tidally locked. From that point on they will remain locked in orbit neither moving away or towards one another unless some other large gravitational force perturbs them (e.g. an extra solar planet wandering through the solar system and passing by earth-luna).

[–] [email protected] 7 points 7 months ago

Ok I read somewhere it would reach it's farthest orbit (29d and half) and stays there then.

[–] [email protected] 2 points 7 months ago (1 children)

I'm gonna be dead center for it here in Ohio, so excited. Got my welding helmet ready to watch it and the day off.

[–] [email protected] 1 points 7 months ago (1 children)

Fuck yes, enjoy bud. I've read people not using high enough rated welding goggles and getting eye damage though. I'd stay on the safe side and get appropriate solar eclipse glasses. You'll be looking directly at the sun for several minutes after all.

[–] [email protected] 2 points 7 months ago

I have shade 14 capable welding helmets, I'm good. I did have to look that up to be sure though. You are right apparently to be worried.

[–] [email protected] 60 points 7 months ago (2 children)

Interesting mix of kilometers and inches...

[–] [email protected] 35 points 7 months ago

As a Canadian, this just seems normal to me.

[–] [email protected] 22 points 7 months ago (1 children)

When do we get to start using kiloinches?

[–] [email protected] 10 points 7 months ago (1 children)

I heard Everest is actually exactly 348 KI, they just thought 348.324 KI sounded more accurate

[–] [email protected] 1 points 7 months ago

I've heard that in feet they originally measured it to 29000 exactly. But they added 2 feet so people didn't think they were estimating the height.

[–] [email protected] 29 points 7 months ago* (last edited 7 months ago) (3 children)

Putting on our moon armour could solve a lot of problems. It's not my most favourite solution though.

PS: Gonggong?!
Edit: dwarf planet. Discovered in 2007 and named after a god in the chinese mythology:

Gonggong was ashamed that he lost the fight with Zhurong, the Chinese god of fire, to claim the throne of Heaven. In a fit of rage, he smashed his head against Buzhou Mountain, one of eight pillars holding up the sky, greatly damaging it and causing the sky to tilt towards the northwest and the Earth to shift to the southeast, which caused great floods and suffering.

🤷‍♀️

[–] [email protected] 8 points 7 months ago

Sounds like someone who didn't learn healthy coping mechanisms.

[–] [email protected] 2 points 7 months ago* (last edited 7 months ago) (1 children)

Ah, it is Chinese, interesting. I'm guessing it's not the gonggong in 公共汽车, because that's a bus.

What, it almost literally is. It's 共工, like "work together"... but not like, go to work together (on the bus).

[–] [email protected] 4 points 7 months ago* (last edited 7 months ago) (1 children)

umm.

These characters have multiple entirely different meanings. How does one find out what the supposed meaning is? Or is it up to the reader to decide?

[–] [email protected] 6 points 7 months ago* (last edited 7 months ago)

Context, apparently the word "set" has 430 meanings in the Oxford dictionary. So there's a lot of ambiguity. It's very confusing but I think we give as good as we get in that regard.

[–] [email protected] 1 points 7 months ago

The old guy from everything everywhere all at once

[–] [email protected] 25 points 7 months ago

Not bad, Jupiter. Considering you have 120x the surface area of earth, that's a lot of moons.

[–] [email protected] 22 points 7 months ago

See Marco Inaros was just trying to give those inners some extra planet armor.

[–] [email protected] 14 points 7 months ago (3 children)

Is our moon really that big? I thought Charon-Pluto is kinda a special cases that they look like twin planets instead

[–] [email protected] 34 points 7 months ago* (last edited 7 months ago) (2 children)

It's the largest relative moon (fifth largest in absolute terms) of any planet (sorry Pluto) and is more than a quarter as large as the earth itself. It's also relatively further from the planet than most moons in the solar system.

Fun fact, you can actually fit every single other planet at the same time in the space between the earth and the moon, with a bit to spare.

[–] [email protected] 33 points 7 months ago

Fun fact, you can actually fit every single other planet at the same time in the space between the earth and the moon, with a bit to spare.

Though, not for very long. Gravity hates when you try things like this.

[–] [email protected] 6 points 7 months ago

Yeah, if you see a real scale moon + earth distance, you wonder why he doesn't just fly away.

[–] [email protected] 14 points 7 months ago (1 children)

I think part of it is that Mt Everest is a lot smaller than you'd think when you're looking at this scale. The moon is only 2% of the Earths volume so when you spread it over the Earths surface it's really like a thin thin film to cover the whole surface. But the truth is that all of human experience is an even thinner film smeared across the surface.

[–] [email protected] 2 points 7 months ago (1 children)

How is 43 km of moon armor a thin surface by any means?

[–] [email protected] 10 points 7 months ago (2 children)

Consider that the earth is ~12700 km in diameter

[–] [email protected] 3 points 7 months ago* (last edited 7 months ago)

Yeah, but from surface to space it's ruthly 100 km, so 43 km is quite the cover. Then again, I get what you are saying. I gues it's a matter of perspective.

[–] [email protected] 1 points 7 months ago

Ah I see. Although the comic spreads the moon "relatively", it presents it absolutely. Although interesting in by itself it does feels it's missing something.

[–] [email protected] 1 points 7 months ago

That's exactly what I was thinking, how is it possible?

[–] [email protected] 13 points 7 months ago

Salacia sounds like what they’d call Risa in the porn version of Star Trek

[–] [email protected] 9 points 7 months ago

https://explainxkcd.com/2908

[–] [email protected] 9 points 7 months ago (1 children)

I mean this does have a practical application, I think. The relative masses of moons to planets does imply the moons ability to sweep junk out of the way before it hits the planet.

[–] [email protected] 3 points 7 months ago* (last edited 7 months ago) (1 children)

This is not based on mass but on volume. For example the moon is only 1% of the earth's mass yet considerably less dense therefore it makes a thicker layer.

[–] [email protected] 1 points 7 months ago

*imply

Sure. By even the density/mechanical properites of armor will affect its usefulness. Beyond simple thickness.

[–] [email protected] 8 points 7 months ago

That's why we live here; the moon protects us!

[–] [email protected] 7 points 7 months ago (2 children)

Finally, Earth is Number One again (well Number Two if you count Pluto, that is)

[–] [email protected] 14 points 7 months ago

That was why we told pluto it couldn't be in the club anymore.

[–] [email protected] 6 points 7 months ago

Pluto-charon shouldn't count since it is more akin to a binary planetary system than a planet-moon system. Charon and Pluto are so close in size that the system has a barycenter outside of Pluto. This means instead of Charon orbiting a point inside Pluto, Charon and Pluto orbit a point about 800 km above Pluto's surface.

[–] [email protected] 4 points 7 months ago

Mercury in shambles

[–] [email protected] 2 points 7 months ago

Earth and moon, rejoined again at last!