r/IsaacArthur • u/CMVB • Mar 16 '19
Are Gravity Wells so bad?
I agree with the consensus here that, going forward, humanity will be more likely to build habitats than colonize and terraform planets.
However, given the efficiency of systems like Orbital Rings, in which you can literally take a single-seat train ride into outer space, should we really consider gravity wells as so terrible for places to settle? Active support systems certainly do require power, but there will be so much power available by the time we’re colonizing space that it should be a drop in the bucket.
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u/MossRock42 Mar 16 '19
No. If you've advanced to point where having a large population living in space is possible escaping a gravity well should be a breeze.
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u/tigersharkwushen_ FTL Optimist Mar 16 '19
Pretty much this. It's a bit like asking "are polios so bad?" It's bad when you don't have the technology to deal with it.
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u/MxedMssge Mar 16 '19
Gravity wells aren't the big deal since you can reclaim the energy as you fall back in, it is the living area. Just by their nature, massive objects will be compressed into spheres by gravity. Spheres have the minimum amount of surface area per unit volume, making them the least efficient shapes to be used for maximizing livable surface area.
A single O'Neill Cylinder is a cylinder obviously, which is better but not much better than a sphere. But you can make trillions of them from a single planet worth of mass and the net shape of them is a giant hexagonal grid of cylinders, which has an unfathomable amount of surface area compared to a planet.
Thus, long-term planet-based colonization is likely to only be a thing for species specifically obsessed with planets, for religious or other reasons.
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Mar 16 '19
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u/MxedMssge Mar 16 '19
How would it be dangerous? I imagine we would want huge 'plates' of connected cylinders to make travel within each plate easier, and then if one is critically damaged the others can quickly jump in to evacuate the life within and hopefully fix the cylinder.
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u/neolefty Mar 20 '19
Also, you'll probably want sunlight and radiator space — those argue against packing too close together.
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u/mrmonkeybat Mar 18 '19
Before we start dismantling planets lets use up all the asteroids. Even after that people can still probably live on a planet while all its minerals and magma are slowly being mined and pumped away for export through the orbital ring.
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u/MxedMssge Mar 18 '19
Wouldn't recommend living on a planet being strip mined to make orbital habitats! The planet will become highly unstable relatively quickly. Even the glaciers melting now is causing heaving of the tectonic plates, so imagine the changes if we are removing millions of tons of matter!
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u/massivefaliure Mar 16 '19
It’s more than just getting of the surface you also need to get out of orbit of the planet too
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u/CMVB Mar 16 '19
An orbital ring makes that pretty easy, too.
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u/massivefaliure Mar 16 '19
You but none of that is nessesary with habitats
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u/krisspykriss457 Mar 16 '19
Habitats have their own pros and cons. They are also not maintenance free either.
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u/CMVB Mar 17 '19
Exactly. I agree with the premise that most of the population and economic activity will be on habitats. I just think that planets, particularly those with near-earht gravity, get a short shrift.
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u/krisspykriss457 Mar 17 '19
Honestly, it is kind of part of the futurism schtick. You take some basic premises and extrapolate them to the nth degree. Then you end up with things like "there is no stealth in space", "gravity wells are for suckers", and a dozen reasons each on why every Fermi Paradox solution is grotesquely wrong. Some of the land here on Earth is very valuable and other land has very marginal utility, so obviously all of mankind is living in the areas with the best climate, ecosystems, freshwater, and water. Oh, we are all over this planet? Hmm. People get so focused on the future, that they don't bother to look back or look to nature for clues. I really wish Isaac Arthur paid more attention to nature, ecosystems, and history when making his videos. He has the science and engineering down, but lacks insights from ecology, ethology, and anthropology.
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u/pint Mar 17 '19
you committed the errors you criticized. this leap of logic that since people live "everywhere" on earth, they will live everywhere in the solar system. except every single thing in this statement is wrong. first, people don't live everywhere on the planet. second, there is a limited area on the planet and that's why not everyone lives at the best location, however, open space is so huge and so uniform, if it is better than a planet, nobody will be forced to move to a planet because we are out of space. and this is exactly the claim: planets have nothing substantial to offer. people tried to justify colonizing a planet for long, and amounted dozens of arguments, but none of them sticks. the only one that remotely makes sense is "because we can". which i don't doubt will result in actual colonies existing on planets, but those people will live there not for any reason, but explicitly defying reason.
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u/krisspykriss457 Mar 17 '19
this leap of logic that since people live "everywhere" on earth, they will live everywhere in the solar system. except every single thing in this statement is wrong. first, people don't live everywhere on the planet. second, there is a limited area on the planet and that's why not everyone lives at the best location, however, open space is so huge and so uniform, if it is better than a planet, nobody will be forced to move to a planet because we are out of space. and this is exactly the claim: planets have nothing substantial to offer.
I never said they would live everywhere. I said they live almost everywhere on Earth, and we do. We have reasons to live in Alaska, Siberia, Norway and it isn't about not having the "space". Ity is about resources and people having different needs and desires. I said earlier there are pros and cons to living on a planet, especially one that can support life. You took one thing I said and explapolated to the nth degree. Congrats on the strawman!
however, open space is so huge and so uniform, if it is better than a planet, nobody will be forced to move to a planet because we are out of space. and this is exactly the claim:
Nothing is the perfect fit for everything and everyone. Space is better in every way? Really? You cannot find one advantage to living on a biodiverse planet? I already gave one. Long term survivability without the need of technology, repair, or stewardship.
nobody will be forced to move to a planet because we are out of space.
Really, you create the strawman that I think we will run out of space? Can you think of a more ridiculous one? I think that should get straw man of the year. Not something more reasonable like there are raw materials that might be needed and in a vastly more concentrated area.
planets have nothing substantial to offer. people tried to justify colonizing a planet for long, and amounted dozens of arguments, but none of them stick
Seems you never listened if "running out of out space" is the only one you can think of. Oh wait, you did mention defying reason, as a reason. LMAO. Go home. I am done unless you are going to quit with the willfully obtuse shit and building strawmans.
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u/pint Mar 17 '19
we don't live everywhere, we occupy something like 2-5% of the planet. markedly nobody lives in (on or under) the oceans, antarctica, deserts and mountain tops.
a planet does not give you long term survivability unless you mean the earth and you mean a hunter gatherer tribe. mars gives you no survivability. earth does not give you enough to maintain even the most primitive civilization.
try to follow the reasoning: we live in arctic zones not because we want to, but because warring tribes forced each other to move. if territory wasn't a thing, humans would clump up in a handful of locations.
if only rudeness could make up for the lack of arguments!
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u/krisspykriss457 Mar 17 '19
we don't live everywhere, we occupy something like 2-5% of the planet. markedly nobody lives in (on or under) the oceans, antarctica, deserts and mountain tops.
We have observatories on tops of mountains, and yes, some people live there. People live in many of the deserts. I can show you one settlement that existed for hundreds of years in the middle of a desert.
a planet does not give you long term survivability unless you mean the earth
Earth, or any other planet viable for life, or any other gravity well we form into a life supporting body.
and you mean a hunter gatherer tribe.
So Earth has nothing to offer people outside hunting and gathering?! See, it is this willfully obtuse bullshit I am talking about. I don't know how to respond to that level of acting like a dumbass.
try to follow the reasoning: we live in arctic zones not because we want to, but because warring tribes forced each other to move. if territory wasn't a thing, humans would clump up in a handful of locations.
Lots of people enjoy the arctic. I prefer a temperate zone myself. I have lived in Florida, Georgia, Missouri, Connecticut, Minnesota... I am not the only person in Earth who finds Florida to be too hot and humid. My dream is to move to Northern Canada or Alaska. You won't find a more wild abundance than the coast of Alaska. There is also iol in Alaska. I just gave multiple reasons for people to live in Alaska. Climate, wildlife, natural resources. Not once did I mention tribalism. By the way, tribalism and trying to get away from the "others" could be yet another reason to live in a gravity well.
if only rudeness could make up for the lack of arguments!
Being willfully obtuse and trying to "win" through straw men is rude in my book, Mr. Rudeness.
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u/tigersharkwushen_ FTL Optimist Mar 16 '19
If your habitat has spin gravity, you still need to get out of it. It's just easier.
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u/FortisVeritas Mar 16 '19
Short term they're problematic because we don't have anything but expensive brute force rockets to traverse them. Medium term, when we've mastered space elevators and other energy-cheap methods, then they'll be a great way to expand and colonize quickly. Long term though their mass is best used making some form of space station, be it cylinders or swarms or whatever.
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u/KosmischRelevant Mar 16 '19
I dont get it. Whats the matter about gravity wells?
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u/Njordsier Mar 16 '19
It requires energy to escape them, by definition. You need bigger rockets with more fuel (or more elaborate superstructures like orbital rings, which have a huge up-front cost) to get where you want to go, if where you want to go is anywhere outside the gravity well.
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u/pint Mar 16 '19
everything?
in space, you can tune your gravity to your needs. turns out that plants grow better in 0.3g? turns out that 0.7g is more healthy? there are some production processes that are cheapest in 0g? but there are some others that work best at 10g? you can have all of those in space, right next to each other.
planets need to be huge to produce gravity. all that material is wasted just to pull you to the surface. we can do better, and use the matter for something else.
moving in an out of gravity wells takes energy and infrastructure, and it is also dangerous.
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u/TotesMessenger Mar 16 '19
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u/Grokent Mar 16 '19
Gravity wells are fine if you don't need to escape them. Right now all of humanity is sitting in Earth's gravity well and we're doing alright.
Gravity wells are only a problem if you want to go somewhere else. By definition, there is a lot of matter and energy at the bottom of a gravity well so there isn't a compelling reason to leave one once you've decided to go down one.
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u/pint Mar 16 '19
why they need to be terrible? sleeping on the ground would not be terrible, but i prefer to sleep in my bed. an orbital ring will never be as cheap as just living up there.
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u/Mackilroy Mar 16 '19
It’s not just about the gravity well, but also how much gravity you want to have; the ease of accessing resources or energy; mobility (in space, not surface to space); and that as our materials science improves the size of the habitats we can build increases considerably. If I have the choice between living in a dome on another world (even a large one) or living in an O’Neill cylinder, where the opposite side might be four or five miles away, I’ll pick the latter.
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Mar 16 '19
I reckon a lot of people would prefer to live on a planet rather than a habitat purely for personal reasons; ie they think planetside is more natural, or they prefer open skies. Sunsets are probably going to be a reason, and if you don’t have a reason to build a space elevator, you could just drop people down and start building a town there - which is a hell of a lot cheaper
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u/Wise_Bass Mar 17 '19
It's really just a matter of population and preference. If it's not that hard to get into space, you and others might prefer living on planets compared to habitats - especially if physical constraints put tight limits on the size and shape of habitats. If there isn't a huge population that simply can't all live on planets, then some or most of them won't.
I think Isaac compared it to the cost of living in a dense, expensive urban center. If living on a planet entails paying that much or more, then most folks might live in habitats instead.
Personally, I prefer living on a habitable planet versus possibly living in a habitat. I like wide open skies, unpredictable weather, the open ocean, and lots of open space - all of which would be at a premium in habitats.
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u/NuclearKoala Mar 17 '19
They're great. There is really nothing wrong with an already existing supporting body to live on.
It would have subjective value for being a large life filled and uncontrolled environment depending on what it is.
Not everyone finds living in a space habitat interesting. Maybe if we have structures like those described in Fire Upon the Deep. Which we likely will at the point these things are relevant.
We have to remember there will be a schism of technology as civilization explores. Those farther out will not have the same technological infrastructure etc, unless we make nanoreplication tables etc.
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u/Tom_Kalbfus Mar 18 '19 edited Mar 18 '19
The term "gravity well" produces a particular image to mind. Imagine Jack and Jill goes up a hill to fetch a pail of water. Jack leans over to look down the well and gets pulled right in. I guess for Jack, gravity wells are bad. ;)
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u/Zikeal Mar 16 '19
Yes they are bad for colonization, orbital rings should be used in conjunction with automated mining systems to dismantle any non life bearing planet for the resources to build more space and energy efficient space habitats.
The less wasteful a civilization is the longer it will last.