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[–] 83 points 1 year ago
[–] 80 points 1 year ago* (3 children)

Being a fan of The Expanse this is really cool. It really puts the size of a lot of the moons and dwarf planets from the series into perspective. Ganymede for example, was used by pregnant mothers in the outer-system because it was large enough to still have an active core and thus a magnetosphere. Shielding the surface from a lot of radiation. Their main food crops were grown there for the same reason.

Io, Callisto, Europa, Eris, Titan, Ceres, and a few others all make appearances too. It's an amazing series, for those who haven't read/seen it, whether you read the books or watch the show.

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  • [–] 7 points 1 year ago (2 children)

    It’s generally a great series but it reminds me of Wheel of Time, in that some of the main characters are incredibly stupid and don’t seem to get any better. James Holden in particular is one whose stupidity is hard to withstand sometimes. I ended up not being able to finish both of those because of that.

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  • [–] 4 points 1 year ago* (last edited 1 year ago) (1 child)

    Yeah, most of James' issues are just him trying to do the right thing. He tends to jump in head first at that point.

    spoilerLike him walking into a clearly radioactive room, despite warning signs being everywhere and a literal siren going off. All because he saw some injured/sick people lying on the ground and he didn't hesitate to help.

    Or flying the ship into a pile of ruble looking for the hybrid (that doesn't happen in the book).

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  • [–] 5 points 1 year ago

    Holden's favourite book, if I recall correctly, is Don Quixote... but instead of seeing it as a satire of sixteenth century Spain and chivalric tradition he sees the antics of the evidently senile and deranged protagonist as a manual of how to act.

    The whole series is Holden tilting at windmills.

    They're quite well written and engaging windmills, though, and there's a lot of great Sancho Panzas to accompany and provide a contrast to our knight errand, so it's still a great series.

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  • [+] 50 points 1 year ago (6 children)
  • [–] 24 points 1 year ago* (last edited 1 year ago) (4 children)

    I can't readily recall the Earth's actual sq. km surface area, and can't remember ever having heard the figure for Mars. Time to drop into Wikipedia and take a gander, I think.

    EDIT: I'll be damned, TIL that the Earth has an area of 510.06 10^6 km², but Mars' is only 144.37 10^6 km², only about 1⁄3 the size (28.3%).

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  • [–] 10 points 1 year ago* (last edited 1 year ago) (2 children)

    The circumference is roughly 40,000 kilometers. The original definition for a meter was such that 10,000 kilometers was the distance from the equator to the poles (so a quarter of the circumference). They got the math slightly wrong and didn't want to people to think the process was wrong so they didn't correct it. I forget the actual circumference but that is close enough for very rough estimates.

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  • [–] 28 points 1 year ago

    Damm Earth is big

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  • [–] 23 points 1 year ago* (last edited 1 year ago) (3 children)

    Thank you! It looked very XKCD to me, so I was surprised when the source link wasn't to that.

    Edit: oops... Meant to reply to the comment with the xkcd link.

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  • [–] 14 points 1 year ago* (2 children)

    Source states:

    All Human Skin

    Where?

    E: found it. Tiny spot northeast of Australia.

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  • [–] 12 points 1 year ago

    Welp, there's my next TTRPG map.

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  • [–] 11 points 1 year ago (6 children)

    TIL Ganymede is bigger than Mercury?

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  • [–] 5 points 1 year ago (4 children)

    Hard to say with the irregular shape, but they're close.

    What really gets me is how small Mars is relative to Earth and Venus.

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  • [–] 2 points 1 year ago (2 children)

    Kinda shows how useless the fantasy of living on Mars really is. Not only is this a barren wasteland, it's also a tiny barren wasteland.

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  • [–] 1 point 1 year ago

    I mean, I wouldn't call it "useless". There's almost certainly a benefit to the science and technology that can move people to Mars safely and transform it into a habitable place.

    But "We're going to Mars!" as a mission is a fantasy. "We're going to keep investing in blue sky research until we have advanced enough technology to make Mars a feasible destination" is where the money is at.

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  • [–] 10 points 1 year ago (15 children)

    Why does earth include the oceans though?

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  • [–] 22 points 1 year ago (14 children)

    Imagine excluding land underneath puddles

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  • [–] 6 points 1 year ago* (last edited 1 year ago) (13 children)

    Ahh I didn't realize, I thought it was only exposed solid surface. Does that mean every other solar system body with water doesn't have separate islands/continents? Because if no, then earth should be depicted as one solid shape without the divisions as well. I get it though, it's for scale.

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  • [–] 10 points 1 year ago* (last edited 1 year ago) (12 children)

    Does that mean every other solar system body with water doesn’t have separate islands/continents?

    Am I reading this wrong, or were you under the impression liquid water isn't a special Earth thing (and the defining factor of the habitable zone)? I'd say you're in the lucky 10,000, but that fact is actually kind of depressing to learn.

    Titan is the only other one with known surface liquids of any kind. I suppose Randall Munroe could have given it's lakes of natural gas the same treatment.

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  • [–] 6 points 1 year ago (8 children)

    Yeah I overestimated a teeny tiny bit the number of places in the solar system that have liquid water on the actual surface. My bad.

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  • [–] 7 points 1 year ago* (last edited 1 year ago) (6 children)

    No problem!

    This is part of the reason why some people are skeptical of human space travel; all the other real estate out there is pretty bad, and looking at this map I realise it's not even that much, really. You basically have barren rocks like the moon, bottomless atmospheres like the gas giants and Venus, and then Titan.

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  • [–] 2 points 1 year ago (5 children)

    Oh yeah, seriously Mars is a really bad choice of an exoplanet to colonize, so small the gravity difference will kill you if none of the other horrible things about it.
    Venus is actually the most reasonable and likely to be habitable but you know... We have to figure out the whole "stop it from melting us" thing and the constant volcano action aint helping.

    We will probably colonize space on asteroids with slave labor before anywhere else in this solar system.

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  • [–] 3 points 1 year ago (4 children)

    Not the moon? It's right there, so it's my pick for airless rock to live on. Mars has slightly more gravity, I suppose. It's not at all known how much you need to be healthy, except more than none.

    With Venus, the most promising option would be living in a air-filled balloon in the upper atmosphere. The pressure and temperature in the right layer is not only tolerable but beautiful, and since it's a mainly CO2 atmosphere such a thing would naturally float. You'd probably have to figure out ways to remotely retrieve things from the surface if you wanted it to be self-sustaining, though.

    Assuming the gravity is okay enough, Titan is promising. For long term habitation we'd probably need nuclear fusion to power things, since solar isn't an option and fission fuel might be scarce, but all the organic elements are there in abundance, and cold is relatively easy to overcome.

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  • [–] 1 point 1 year ago (3 children)

    The moon is a good staging area for rocket launches because of the low gravity but the moon wars will be rough on it i bet and its not like there is a glut of material we can strip from them unlike asteroids and if we destroy it we are gonna be really messed up as a planet.
    Plus low gravity is almost worse than no gravity really. We cant spin the moon around faster but we can strap some asteroids together and make some weird stations with lots of metals that are right there. Low gravity of the moon and Mars actually will likely cause so many clots that you end up blind within 7 years and dead shortly after and we cant easily mimic or add more gravity.

    Venus and jupiter both strike me as floating habitation if we ever get there but the moons of jupiter are fantastic and also 5 and a half years of flying away. So not gonna be a super useful base unless we figure out a different means of travel.

    Im still a big fan of Europa and finding out if we do have an alien competition in this solar system.

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  • [–] 1 point 1 year ago* (last edited 1 year ago) (2 children)

    The moon is a good staging area for rocket launches

    Yes, they might actually be able to pay for things from Earth with domestic industry servicing things further out. Nowhere else has an economic "pull" for humans beyond novelty.

    Low gravity of the moon and Mars actually will likely cause so many clots that you end up blind within 7 years and dead shortly after and we cant easily mimic or add more gravity.

    Source? What I've seen makes it sound like a true medical mystery, at least until we have more data.

    We cant spin the moon around faster

    You could put a rotating band with a bit of inwards tilt along the ground, which would achieve something similar.

    Space stations are also an option; I guess I really should include them. The disadvantage relative to barren rocks is that they have a certain maximum size given what materials are locally available; there's no expanding out over centuries like we're used to on Earth, and you definitely need artificial gravity. You also might need to import a significant amount of volatiles like hydrogen, if it's a near-Earth asteroid. The advantage is the sheer variety of places to put them, and easy access to zero gravity when actually desirable.

    I don't know about floating on Jupiter. Nothing really floats in hydrogen, it's extremely cold, and the gravity would be multiple Gs. Venus has pretty much the same gravity as here, as well as the layer of room temperature and pressure gas.

    Im still a big fan of Europa and finding out if we do have an alien competition in this solar system.

    Don't forget robots are an option, if we just want knowledge or to mine various rare-on-Earth substances.

    In the long run, interstellar travel seems possible, although we'd have to be very patient.

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  • [–] 1 point 1 year ago (1 child)

    I studied theoretical astrophysics and astro xenobiology and part of a thought experiment we did was on the long term affects of low gravity habitation. While we mostly have zero gravity studies the whole 1/3rd or less of our gravity makes some extrapolations pretty simple like cell wall thinning and the whole clots thing, and the small cardiovascular tubes of the eyes make for some good starting points to notice the effects, especially blindness.

    But yeah the physical moving items with friction in a light gravity situation pose a pretty big issue for those rotating rings. While a lashed together collection of asteroids can be pretty rough but in a no gravity situation can be operated like a space station of its own. And a large station can be spun slower than the small rings needed for a planetary surface. Recent short paper on this https://ntrs.nasa.gov/api/citations/20210019591/downloads/ICES-2021-142.pdf

    For Jupiter that is some really sci-fi stuff i have seen for it but essentially we could build a vacuum based balloon, the high amounts of hydrogen and helium make for great fuel resources and there are lots of other materials immediately in the area and water from Jupiter's atmosphere. Though the physics on the dirigible are silly and way far from something we are doing soon and so is any of this kind of speculation.

    Unfortunately the nearest and most likely option is the ugly we go out and start grabbing asteroids and making a really ugly space station that works.

    And also robots are not an option. You have clearly never sat on a clean meeting from COSPAR's Planetary Prevention policies. We get zero room for contamination to the poont where my mentor just suggested shooting a solid copper ball from orbit and collecting the exploding dust since it was the only way to follow all the protocols. Once people stop caring, people are cheaper, less rare, and have their own fabrication system built in.

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  • [–] 1 point 1 year ago

    You have to build and move a miniature Earth ecosystem just to support a person, since the only way to make food to date is with other organisms. Even in a fixed structure right here that's proven hard; Biosphere 2 had to be aborted.

    NASA has done all probes in exploration outside of Earth's own system for basically that reason. How does that not come up in an academic meeting?

    And vacuum balloons can't be made out of any real materials, and wouldn't solve the gravity too strong to stand in, and carousels exist on Earth, and if it's not cantilevered you should use linear tangential velocity which has to be higher for a bigger ring, and biological systems aren't linear and can't necessarily just be extrapolated out...


    Alternate link for that paper, which actually is a good source. I think the last time I heard about (the lack of) progress on the problem was from Zach and Kelly Wienersmith on the Nature Podcast. I don't know who exactly would disagree with the "roughly proportional" take here, but I'd be surprised if that was just a fabrication. Proportionality also brings up questions about if higher-than-Earth gravity would then be better for us.

    Anyone reading can find a ton more papers on space stuff through ICES, which looks neat.

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  • [–] 4 points 1 year ago (2 children)

    What is the lucky 10,000?

    Also aren’t there other moons of that gas giants that have liquids like liquid methane(?) where people speculate there could be types of life?

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  • [–] 9 points 1 year ago (3 children)

    Why does this look like bootleg Tamriel sans the high elf island I can't remember the name of fuck off Sheogorath it is not the Shivering Isles.

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  • [–] 14 points 1 year ago (5 children)

    I guess fact it's mostly gas means I don't have to ask, "where's Uranus?"

    But if we're counting the liquid parts of Earth, shouldn't we include the squashy centers of Uranus and Jupiter?

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  • [–] 3 points 1 year ago (1 child)

    Yes, I was wondering the same question. Jupiter surface would definitely dwarf anything else

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  • [–] 3 points 1 year ago

    Jupiter has no surface, just a gradually increasing density. When you sink in the ocean, you eventually reach the ocean floor. On Jupiter you just keep sinking until your surroundings match your density.

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  • [–] 3 points 1 year ago

    The "liquid parts" of earth are just a thin puddle over basically the same solid shell covering the rest of the planet, relatively speaking. Uranus does have a small rocky core (so probably should have been included tbh), but Jupiter's core is just liquid and doesn't even have a clear boundary between the gas and the core.

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  • [–] 14 points 1 year ago (3 children)

    What's the unlabeled one?

    /s

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  • [–] 6 points 1 year ago

    There really is an xkcd for everything.

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  • [–] 5 points 1 year ago

    Made me think of lake mobius from hunter x hunter :3 that's way bigger tho

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  • [–] 5 points 1 year ago* (4 children)

    The atmosphere must be intense (incredibly dense, solid on the rocky surface) as I assume all the gas planets are included too, just all over the place :D.

    Unless it's a flattt world and the excess gas just fell off.

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  • [–] 2 points 1 year ago (1 child)

    Let's just say, that's not ocean surrounding it :p

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  • [–] 1 point 1 year ago

    Haha, that works too - a not too seriously sci sci-fi (the kind where your shouldn't question the science part bcs it's one plot hole after another) would make up a space race that takes rocks in a solar system & floats them on a gas giant like an island.

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  • [–] 6 points 1 year ago

    Pangea is bigger than anyone thought. Cool.

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  • [–] 3 points 1 year ago (5 children)
  • [+] 3 points 1 year ago (9 children)
  • [–] 17 points 1 year ago (8 children)

    Isnt Jupiter mostly gas/liquid with only a solid core?

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  • [–] 11 points 1 year ago (3 children)

    Does it even have a solid core?

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  • [–] 11 points 1 year ago (2 children)

    probably? according to this diagram, it consists mostly of metallic hydrogen, which i interpret to mean "hydrogen in a solid phase".

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  • [–] 10 points 1 year ago (1 child)

    Metallic Hydrogen apparently just means "hydrogen in a state that conducts electricity". No idea what kind of pressure and temperate would form actually solid hydrogen, but from my understanding the gas giants are quite hot internally.

    And by that diagram the core would be massive.

    From what I can see it's a diffuse core, meaning it's a gas until it isn't, but with no real line between the two.

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  • yeah i read up on it and all four giants (jupiter, saturn, uranus, neptune) have no "clear" surface: they all have a gaseous atmosphere on the surface, but when you go down, it goes above the critical point and therefore continuously changes into a liquid phase with no clear line in between. very deep inside, they all have cores made from rocks, but it's rather small compared to the total size of the planet.

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  • [–] 1 point 1 year ago (3 children)
  • [–] 13 points 1 year ago (2 children)

    The thing about Jupiter is that if it has a solid core (IIRC it's not 100% sure yet, though maybe things have changed since I last checked), there's still no surface. As you go down, it just goes from gas through liquid to solid gradually without any clear boundaries.

    If you were to "land" there, you'd just sink down until you reached the depth with the same density as your vehicle and stay there.

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  • [–] 2 points 1 year ago (1 child)

    Oh, I get why Jupiter our biggest planet is not here. Because its surface is made from gas, not land

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  • [–] 3 points 1 year ago

    Mad tamriel vibes from this.

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  • [–] -5 points 1 year ago (2 children)

    So all planets are covered in oceans? Brilliant map for sure! /s

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  • [–] 3 points 1 year ago (1 child)

    The next step would be to map the heights as well, but I bet that looks like a mess. Plus... I mean, what do you even set as sea level? Do you start counting from Earth's deepest point and go from there? Highest point? Average?

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  • [–] 0 points 1 year ago (3 children)

    I dont really agree with counting the oceans but not counting the gaseous areas of the gas giants, but i guess it getd messy with how to portray it. Portray it as a liquid form of the gases so you have definite volume? Remove the liquids from the equation (but that would create MORE land on earth)? I dont know. It just seems like removing them from the equation creats an extremely small picture, but maybe that's the point.

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  • 2 comments in c/mars@discuss.tchncs.de view that post
    [–] 2 points 1 year ago (1 child)

    Where's Jupiter? And Mars is smaller than Earth?

    I don't think I understand this map.

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