Also I think that terraforming Mars is a red herring. Are we really short of lebensraum on Earth? Easier to build cities and extract resources in Canada, Antarctica, the deep oceans, Russia, the Sahara.
All near-future space stories have this "problem". There's no good reason for humans to go live in space (besides escaping the "single planet trap" which hedges against catastrophes that are extremely unlikely, many of which would still leave the surviving humans on earth better of than the humans surviving in our potential colonies). The technology required to teraform Mars or building O'Neill cylinders would also fix most problems on earth, just orders of magnitude cheaper.
Let's get offworld certainly, advance as a civilization, secure Mars... but only with good reason. The costs must be outweighed by the benefits
What benefits?
What about Mercury, is there not a tonne of solar power there?
Around twice the delta-V of a Mars mission, if you start from Earth orbit. And for what, 7x the solar irradiance of Earth? Just built 7x the amount of panels here. That's going to be cheaper than shipping the panels (or the panel factories) to Mercury for a very, very long time. Also, once you have heavy industry on Mercury, you need to ship the... heavy goods back out, quickly depleting what little water there is on Mercury.
There are resources in the asteroids, let's get them.
Almost all asteroids are worse sources of metals than a decent mine on earth. So you get into a chicken-or-egg problem with asteroid mining: the only reason why you'd want to do it is because those resources are already in space. But if the only thing to built in space is infrastructure for getting resources, you can just skip the entire space-headache and do your project on Earth for a fraction of the cost!
In the end, it's an awesome scenario for stories, and we like telling stories. Either for entertainment, or for inspiration. But realistically/economically, I don't see a case for human space flight at all. And if you want to build cool/inspirational stuff, you can do a whole lot just with our moon and the space around it.
pbmonster
2mo ago
Is it just that cargo ships don't have much of a keel, so they only benefit from the component of the wind that's parallel to their course?
Can't imagine that's the case. The combination of tens of feet of draft and more than 10:1 aspect ratio of the hull should make significant lateral slip almost impossible. Even if sideward movement would be a problem, a relatively small, retractable foil at the front of the vessel should be able to compensate for that (in combination with the rudder).
I suspect bunker fuel is just to cheap. A kite system is purely additive (you need everything on board you've always needed, and then there's the new kite). So you save a couple of thousand dollars per day on fuel - if you're not becalmed, large parts of the Atlantic and Pacific are notoriously calm - but now need to train crew, maintain a new system, pay off the additional capex and deal with additional risk. The amortization period is probably to long for such a conservative industry.
When really using a shovel properly, hard, throughout a day, is a much more complicated physical task than the bench press is. Experience completing labor tasks will add to your ability in those tasks, no different from any athletic specialization.
I think most of the gym strength vs labor strength comes down to this.
On a practical level, most construction workers will have the added advantage of having both much higher work capacity in the movements most relevant to their work - gym strength is not commonly built by doing hundreds of reps (per hour, for 10 hours, in the sun) - and by having already built the mental fortitude necessary to complete hundreds of reps (per hour, for 10 hours, in the sun).
if someone tells me that they are strong but not with "gym muscles" then I know they aren't actually all that strong at all
The laborer will of course turn that around. The inability (in work capacity or mental fortitude) to lift all day is the same as not being "all that strong at all" - no matter what the little numbers on the plates say when they get moved around for a grand total of 10 minutes every other day.
pbmonster
2mo ago
They weren't strong
Often, they were extremely strong a decade (or two) ago, and are now in a chill, but meticulously managed decline. Especially if they managed to avoid long injuries, their muscles might not be bulging anymore, and might be covered by a layer of fat, but the muscle mass is still mostly there. Advanced age and sinking testosterone levels makes building muscle much more difficult, but careful maintenance is doable.
It's even more apparent in the endurance sports. If you look at 10k/half marathon/marathon times of senior/grandmaster division runners, they often maintain impressive amateur times into their sixties. The real performance cliff only seems to come in the late sixties.
but they knew how to leverage what strength they had.
This is, of course, also true.
pbmonster
2mo ago
The clothes themselves seem to be pretty standard ones, similar to what I see in every store, not some junk or second hand ones, so they must cost something? How these costs are covered? How are they ensured against loss or theft?
The answer to all of that is that those clothes cost almost nothing when you directly import them from China/Bangladesh/Vietnam. Single dollars, often cents, per item. It's all mass produced plastic garbage.
Go onto shein.com and sort cloths by "price, ascending". Bulk is even cheaper than that.
pbmonster
2mo ago
The clothes are sourced from others in the community, maybe a couple of whom acquire big volume discount merchandise from discount store closings, perhaps wholesale outlets etc, then sell them on.
And frequently, it's just the same plastic garbage Shein/Wish/AliExpress is selling, imported in bulk.
On vacation, my wife tried getting a cheap beach dress from those stands, the only criteria being "cotton or linen" and "kinda fits". The entire operation was abandoned because the first 5 people we tried didn't have a single piece of clothing not made of plastics.
pbmonster
2mo ago
That's also probably the ideal vessel for a sail system. Transporting bulky rocket parts below deck makes mounting the sails/masts straight forward, the low density cargo doesn't require a large displacement hull, and the ship probably doesn't need to run on a tight schedule. Container ships would have much more trouble finding room for the sails, and with more draft comes more hydrodynamic resistance, and so a requirement for much larger sails.
But maybe bulk carriers could get foils mounted cheaply and quickly. Even 0.1% fuel savings are a big deal in the industry.
Now I'm wondering what happened to all those startups that tried lashing a robotic kite to cargo ships...
pbmonster
2mo ago
I took a total of 14 days to complete the route, with 12 being “par”. Per day, I averaged:
72 kilometers 2050 meters of elevation gain 5,000 calories of energy expenditure
Hardo. Congratulations!
Beef is my favorite protein – the Eastern Swiss essentially don’t eat it because their income is tied to the cows staying alive. [...] The main dish is pork schnitzel. Maybe chicken nuggets if you’re lucky?
Did you exclusively go to the cheapest hole-in-the-wall farmer's pubs? Entrecote (beef) and cordon blue (veal) are absolute staples in traditional Swiss restaurants, and the restaurants like selling those because the margins are much better than the pork schnitzels.
Even the grocery stores are the size of a small American apartment and almost exclusively stock pork and dairy as calorie sources.
Grocery stores will have lots of pork, but again, the higher quality cuts of beef will always be available. Yes, the deli meat section will have not much other sources, and small stores might not have ground beef (only ground pork), but there's always a random cut of beef steak. Did you get the chance to visit a butcher shop?
There’s no side dish at any restaurant that’s not a potato.
Come on, the Swiss love their risotto rice and their Italian pasta.
pbmonster
2mo ago
For keeping me around? Same as most other team sports: charismatic coach, fun team mates, good built in social scene. Do you regularly go out for drinks/dinner after practice? Are your team mates... normal? I stopped kickboxing and BJJ because those attract a type of guys I can't hang with, in large numbers.
For starting? Convince me this is either more fun or a better workout than football/basketball/handball. Since I like the look of the classic swimmer physique, I'm already predisposed to believing the workout angle. Maybe stand next to your most broad-shouldered-and-slim-waisted team mate while recruiting.
Also, how's the learning curve? Am I going to be useless for the first year? That's no fun, I'd rather run after a ball if that's the case.
pbmonster
2mo ago
True, but this was in response to a man who's 6'2" (and as such scratching the 2σ barrier) and questioning his BMI.
Waist-to-height ratio is arguably even easier: easier to measure, easier to calculate, more reliable.
I'm 6'2" and was 155 for a long time. I look skeletal in those pictures. I don't look much better in later photographs where I was 170. That's a 20-22 BMI.
BMI is a flawed metric to begin with, but especially so for tall people. And the medical establishment knows that, too, because it's pretty obvious. If you take any random population and plot their weight vs. their height, you won't get a height^2 parabola as your best fit. It's much closer to height^2.5. Which is entirely unsurprising to me, I never understood why anyone would assume that width/depth of the human body correlate strictly linear with height...
But classic BMI has momentum now, people know it and understand it. Most of them don't carry a lot of muscle, and aren't significantly more than a standard deviations from the mean in height. So I guess it's fine.
Still, using the waist-to-height ratio instead is probably an easy fix, and gives more reliable results, even for tall and/or muscular people.
a lot of dogs are useless (e.g. toy breeds) or damaged (e.g. overly-large German Shepherds with hip dysplasia).
Come on, that's obviously only a side effect of our bored decadence. We made those long after we got good guard dogs, shepherds, rat terriers, badger chasers and a dozens of more useful specializations.
And sure, we might well fear a repeat of that tendency when we start selecting traits in our children, but in the end parents still want their kids to be successful, not ornamental. But yes, I hope for the sake of our grand daughters that chest size is not determined by a small number of genes.
pbmonster
3mo ago
But, as anyone here is likely to know, random traits are randomly distributed (often on a Gaussian scale), and the more you filter your results on one axis the more you'll have to tolerate imperfections on the others. So if you filter the child on height, BMI, eye color, you'll have to make some compromises on ADHD and IQ, most likely.
I'm not convinced. Humanity has a long and successful history of breeding for strict usefulness - which often ends up being the same as fitness.
Wild hogs interbreeding with escaped factory farming sows have led to feral hog sounders orders is magnitude more troublesome than wild hogs ever where in the past.
Pick any natural environment that ever had wild horses. You'll find a breed of domesticated horse that, when allowed to go feral, would outcompete the native wild horses, and quickly. Humans have made them larger/stronger/sturdier than nature ever could.
My fear is that selective breeding will allow humans to do the same to their children. And just like street dogs, which effortlessly outcompete coyotes and wolves in urban environments, those designer babies could end up strictly superior in the environment they are made for. As with the hogs, some interbreeding with the "wild" population might improve the end result significantly.
Now, with horses, hogs and dogs we need thousands of generations to get results. The question is how much this process is accelerated by direct gene selection.
pbmonster
3mo ago
From a purely physical/technical perspective, modern refrigerants are fine.
Even refrigerants that completely satisfy our modem sensibilities (low global warming potential, zero ozone depletion potential) work as well as they always did. There's no magic sauce in those old fluorocarbons. Hell, even propane and CO2 are basically ideal refrigerants (but require a complete redesign of the cooling circuit, with much beefier parts to allow for much higher pressures).
If legacy AC systems seem to have more power, I'd assume they come with a more powerful compressor, and without pesky electronics that limit that power in any way.
pbmonster
3mo ago
Counter anecdote: many parts of Switzerland have serious restrictions on residential AC. Some cities have outright banned them (Basel, Geneva), others require the AC to be powered by solar panels, others just don't allow the heat exchanger of a mini split to be attached to the facade of a building. Those two are de-facto bans on AC in apartments.
When you're talking about Europe, regulations like that will vary wildly between locations, and you'll always find anecdotes supporting whatever side you picked.
pbmonster
3mo ago
As a patriarch you're the head of your own nuclear family. On the other hand, your uncle and grandpa are above you in the social hierarchy, and as long as they adhere to social norms, they are deputized to intervene in your life in case you're failing in your life as a patriarch
Note that they might stop you from starting a nuclear family for reasons real (you don't have the material means - and no, they won't allot you any) or imagined (you'll get your part of the family acreage once you're acting a little bit more "grown up").
pbmonster
3mo ago
For example, Denmark
Bad example for a discussion about Hungary. Denmark is easily among the most progressive Euro countries in that regard, while Hungary is equally as easy among the most, probably the most, conservative.
Never underestimate how culturally heterogeneous the Euros are.
pbmonster
3mo ago
I think addictive potential is individual, both in the type of game and the degree.
I never found the hooks World of Warcraft and Diablo try to deploy appealing, but Civilization or Factorio are like crack for me. I also banned myself from ever getting Baldurs Gate 3, after sinking four digits worth of hours into BioWare's discography during my youth.
Sadly, this wasn't to last - [Red Wing Irish Setter Moc Toes] finally gave up the ghost, and will require submission to a cobbler and a resole(if possible) to continue their use for years to come.
I wear a pair of Iron Rangers about 100 days per year, and have been for the last... 17 years (damn, time flies). They need a new heel about every second year, and a complete resole every 4 years.
For the resole, I just send them to Red Wing directly. It's around $130, I think. They're gone for a few weeks over the summer, then they return completely rebuilt with new, original soles. On one of the first resoles, I asked the cobbler if he could use the vibram sole from the Red Wing Beckman instead of the original leather sole from the Iron Ranger (since the leather soles are extremely slippery in mud and snow) - no problem, looks perfect.
Love those shoes.
pbmonster
3mo ago
The way you typically put energy in is to have a fast-moving neutron that is flying in to hit the mercury-198 atom. When you do the calculation, the required energy in for the neutron is just under 8.5MeV.
[Uranium/plutonium fission] produce a spectrum of neutron energies, but the peak of that spectrum (the most number of neutrons produced) is around 0.7MeV, the average being about 1.9MeV
That is, the short answer is that existing fission reactors just don't produce enough neutrons that have enough energy to convert mercury isotopes
Makes perfect sense, thank's for writing it all out!
pbmonster
3mo ago
I'm going through an MIT OCW nuclear course right now.
Then you seem like the best person to ask this rather obvious question: why is nobody doing that in conventional fission reactors right now? At least the fast breeders should have suitable neutron flux, right?
One obvious point seems to be that a a Geran-2 weights 200kg, 60kg of which is the warhead. When it's launched in a wave of several hundred, at night and accompanied by decoys, it currently does OK at reaching its target.
Adding hundreds of balloons to this operation (I don't think you'd want more than 2 drones per balloon, that's a large payload already for a lighter-than-air vehicle) is unlikely to decrease the cost per hit. Especially when compared to just doubling Geran-2 production again.
pbmonster
3mo ago
Small phased array radar is going to bring down thunder and fire on you. If you're spewing out EM emissions on the front lines of a modern battlefield you're going to be in trouble.
For now, you could go with 80 GHz automotive radars. Extremely short range, most current military radar equipment won't detect those ultra high frequencies, and it always could just be a newer Mercedes on adaptive cruise control.
Also, the sensors are cheap (because automotive sensors are a cut-throat business) completely integrated packages (even the phased antenna array needs to be directly on-chip), and at that frequency it's trivial to not only detect the quadcopter, you detect every single moving blade of its propellers, and the rounds you're shooting at it.
pbmonster
3mo ago
If what you're saying were true, doing homeschooling successfully would be much easier than it actually is, and it would be much more common. But the opposite is the case. I have yet to meet a single homeschooled kid I'm impressed by. And those kids certainly did more than 3 years of learning.
To me it seemed that he design the gift economy some of the Martians end up with to be pretty utopian. But yes, he does't dwell on it, or even elaborate very much.
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