Perhaps the median would be better; I'm not especially well versed in statistics. I don't think it would effect the point I'm making in this case, though.
If you disagree, I'd be interested to see you provide some example calculations demonstrating why. The choice is kind of arbitrary, regardless.
an internal combustion engine - as used in a petrol-driven vehicle - gets around 20% efficiency
Actually, the engines themselves are 30% to 40% efficient on modern gasoline-powered cars. There are some additional losses in the transmission, which is something like 95 to 98% efficient. Running outside the optimal load range also makes the engine a lot less efficient, but that's only relevant in stop-and-go traffic, and hybrid electric systems largely solve the issue. Even non-hybrid cars do a lot better in this respect than they used to, by automatically stopping and starting the engine at lights, and having more gears.
The efficiency of the complete drivetrain of a new ICE vehicle is 20% (standard) to 35% (efficient hybrid) for stop-and-go, and considerably better on the highway.
That's 6.189km per kWh, or about 162 grams of carbon dioxide of emissions - using worst case carbon generation - per km travelled.
Electric cars aren't 100% efficient, either; total up the losses in charging and discharging (86% efficient), power conversion (97%), and the motor(s) themselves (91%), and the total efficiency of the drive train is more like 76%.
An electric car? The infrastructure is already in place; there is negligible marginal cost in getting the power from the plant to the car.
That's not true. Even in the USA, grid transmission is only about 94% efficient. (It's much worse in developing countries; for India it's estimated at 70%. The huge difference is because building and maintaining reliable, efficient power transmission and distribution is not cheap, and some places are too poor to do it well.)
So best case, with a diesel S-class vehicle, you're about one third better than the Model S; worst case (5+ litre petrol engine), you're 50% worse.
We must adjust your 162 g/km estimate upward by 40% to account for the EV inefficiencies that you ignored, which gives us a revised estimate of 227 g/km - worse than all but the most over-powered of the four Mercedes models found in the document that you linked.
Another factor to consider as well is the cost of transporting the fuel: trucks have to carry that fuel (diesel, petrol, etc.) to the station, and you have to drive to the station to refuel.
You can't pretend this is a useful or fair comparison if you only consider the supply chain for the contents of the ICE car's gas tank, and ignore everything else. Mining and moving coal has a substantial environmental and economic impact as well. So does mining Lithium for batteries, or refining and doping Silicon for solar panels, etc.
There are really only two reasonable ways to estimate the true environmental impact of a product: 1) Start from nothing but labour and raw natural resources (think minerals still in the ground, not steel) and work your way up every stage of the production, supply, and maintenance chain - you can't assume trains are moving coal, until you've figured out the full impact of making and running trains from scratch. 2) Or, assume that the selling price of an item already accounts for its environmental impact (partially true).
(1) is probably more accurate, but if you're going to do it you need to do it for everything, or at least apply
Tesla M 3 start at the average price of a sold car in America
No. The average price of a car sold in America is about $22,000, whereas the Tesla Model 3 starts at $35,000.
The average new car purchase costs $33,560. However, 69% of cars sold are used with an average price of $16,800, because most people can't really afford to buy new. Furthermore, those numbers are probably the arithmetic mean, whereas the geometric mean (surely a lower number) would probably be more useful.
Anecdotally, the geometric mean price of a car purchase among my own social circles (which encompass everything from the intermittently homeless up to the beginning of the upper class) is definitely MUCH less than $35,000, with a strong majority of the vehicles purchased being used. Anyone who thinks a $35,000 car is affordable to the average American adult is out-of-touch with the true economic condition of the general population.
Some used 2017 Teslas might reach affordability for regular people in five years or so - or they might not; nobody knows for sure what the maintenance requirements and depreciation rate for the Model 3 will be like, yet.
Covering a habitat in space rocks as extra shielding is sensible, as long as you don't need to change your trajectory while taking the extra shielding with you.
However, I don't think NASA has any zero-g activities planned for the foreseeable future which meet that criteria, and even if they did it would probably be much cheaper and safer to just bring some empty bags with them, instead of trying to fabricate them out of asteroid glass in space. Making things during the mission only really makes sense if it's really easy and you need tons of the stuff (like water, oxygen, hydrogen, and maybe methane or ammonia).
Non-trivial space/extra-terrestrial manufacturing is unlikely to pay for itself unless and until mankind's activities grow beyond the level of the occasional tiny research mission. The contract discussed in the article is part of NASA's efforts to figure out how to send more tiny research missions beyond LEO, and has nothing to do (directly) with a hypothetical sci-fi colonization effort.
... cool very slowly... annealing... foot or two thick... best to have two layers and run, say, paraffin (US meaning) in between... volatiles go off with the pre-heating (and are collected separately, because there are as valuable as the rest)
All of that makes sense, and would probably help a ton - but, it also makes the whole process a lot more complex than the AC's proposal, and majorly ups the required equipment and technology level. It could be useful to a hypothetical far-future colonization project, but would certainly be far more trouble than it was worth for any of NASA's planned activities over the next few decades.
The subject of the article, and my reply, was NASA, an organization which currently has no mandate or funding for establishing random asteroid bases in the middle of nowhere. They are, however, theoretically working towards a manned Mars - or maybe Moon - mission, which will require habitats light enough to economically move around.
Even if they were commissioned to build a habitat on some random asteroid, the proposed glass bubble doesn't actually help with that unless it can be made strong and airtight very easily (meaning, using less launch mass and research funding than just sending a hull from Earth). Better to just ship out a high-tech inflatable habitat or something, and maybe cover it with raw space rock/dust/ice for extra shielding from radiation and micro meteorites.
Use big mirrors and sunlight to heat space rock until it goes lava. Then blow gas inside the molten blob until it is big enough for your needs. Let it cool down, add holes for doors and windows.
Glass is brittle and tends to fracture. Don't expect junky mystery glass to hold up well long-term against micro-meteorite impacts - especially if it's made thin enough not to crack right away from thermal contraction during the cooling process. Cracks = leaks.
Even if it turned out to be practical to make something truly airtight via your technique, the result would still be super heavy compared to the high-tech alternatives favoured by the space industry: even homogeneous, high-quality synthetic glass has a poor strength-to-mass ratio as compared to structural metals (aluminium, steel, titanium) or synthetic fibres (kevlar, carbon fibre, etc.).
NASA wants maximum reliability (for both political and moral reasons) and minimum weight, because the cost of sending even lightweight manned spacecraft to Mars and back is already more than they can actually afford. What problem does melting space rocks solve for them?
Unlike Australis, Classic Theme Restorer is very configurable and allows elements from the new and the old theme to be mixed-and-matched freely. Visually, I am using the new theme, but I use Classic Theme Restorer to tweak various small things about it for better usability.
Also, imagine a line of people standing single-file, extending infinitely in both directions. There are, of course, an infinite number of people. Now, imagine each of these people is joined by a partner. Are there twice as many people now? Does this mean there are "2 x infinity" people? But surely you can't do that to infinity. Er...
Spoiler; I'm not a mathematician, and don't have the answers, I'm just throwing this out here for amusement. Though I guess someone who knows more about this than I do could explain it
Modern mathematics recognizes the existence of different "sizes" of infinity, but they don't follow the standard rules of arithmetic. The basic idea is not complicated: anyone who can grasp intermediate algebra should be able to understand it, eventually. (I'm sure that my explanation won't be good enough for a lot of people though; try searching YouTube for "Hillbert's Hotel paradox", maybe.)
However, the infinite is far outside our everyday experience, so a bit of vocabulary from higher math will make it a lot easier to discuss the examples which follow:
set - an unordered collection of unique elements. Elements can be numbers, names, other sets, or whatever. Duplicate elements are not allowed: the number 53 (for example) is either in a particular set, or it is not; the set cannot contain two "copies" of 53, or anything like that.
cardinality - this is the "size" of a set. Two sets have the same cardinality if and only if their members can be put in one-to-one correspondence. For sets with a finite number of elements, such as the set of letters in the English alphabet, the cardinality is simply the number of elements in the set: 26, in this case. This is easily proven by simply associating a number with each letter (A => 1, B => 2, C => 3,...).
Where things get interesting, is when we try to compare the sizes of two infinite sets, such as the set of all even numbers (0, 2, 4, 6,...) versus the set of all whole numbers (0, 1, 2, 3, 4,...). We cannot simply count the number of elements using finite whole numbers. Instead, we must use transfinite cardinal numbers. To understand what those are, consider some classic examples:
Hillbert's Paradox of the Grand Hotel
Imagine that Hillbert's Hotel has an infinite number of rooms, every one of which is occupied by exactly one person. The rooms are each numbered with a sign on the door: 1, 2, 3, 4,...
Question: A new guest arrives, and asks the host for a private room. Can the host provide him with a room without doubling anyone up, or kicking anyone out of the hotel?
Answer: Surprisingly, yes he can! Here's one way he could do so: the host gets on the public address system and instructs every guest to pack his bags, leave his room, look at the number on the door, add one to it, and move into the room with that new number. So, the guy in room #1 moves into #2, the guy in #2 moves into #3, and so on.
At a finite hotel, this could never work: whoever was in the last room would be kicked out, with no higher numbered room to move into. However, in Hillbert's infinite hotel there is no last room, and so there is no problem. Everyone moves over by one room, and the new guest moves into room #1.
Conclusion:infinity + 1 = infinity.
Question: Suppose that the neighbouring Cantor's Infinite Hotel (same setup) needs to be fumigated (or nuked from orbit) because it is infested with an infinite number of cockroaches. The manager of Cantor's Hotel asks the host of Hilbert's Hotel if he can temporarily accommodate an infinite crowd of additio
Are you too incompetent to copy-and-paste, or do I detect a wee bit of malice in the way that you misquoted me?
The point of Hanlon's razor is that it's a good life strategy.
Deliberately putting one's head in the sand is not a good life strategy.
Feeling that someone's out to get you, especially when there's nothing you can really do about it, will not make you more happy.
Who told you that "there's nothing you can really do about it"? Incompetence and malice call for different responses, and thus attempting to distinguish between them is useful.
When a business sends me incorrect bills by accident, I should correct the error and double-check their figures in the future. If such errors occur frequently, I should politely complain to management and encourage them to figure out why their billing process is so flaky, and fix it. This action is helpful to myself, the business, and their other customers: honest mistakes don't necessarily favour one party over the other; they just sow confusion and it is in everyone's interest to prevent them if reasonably possible.
When a business defrauds me on purpose, I should end my relationship with them as soon as possible, and/or threaten legal action. Otherwise they'll just keep looking for ways to cheat me - possibly a way that I'm not clever enough to spot, next time.
Neither of those approaches is useless, but matching the approach to the situation is important - but Hanlon's Razor would prevent me from even trying most of the time.
It's not pedantry; if you read what I wrote more carefully you'll see that it does not depend upon a literal definition of "never". (Unless you insist upon committing the same error in interpreting my words, which you accuse me of committing with yours.)
However, "usually" and "always" are still very different words even allowing for the normal imprecision of humans speech: "usually" simply means "more than half the time", whereas "always" means "an overwhelming majority of the time".
It is simply not true that malice/greed is so rare that its occurrence can reasonably be ignored by default, and you know it. Society has rules, judges, and enforcers (not just talking about the government here - think parents, teachers, sports referees, etc. too) for a reason: because people lie, cheat, and steal quite frequently - especially when they think they can get away with it.
Big businesses break the rules all the time, often intentionally. We know this because they get caught sometimes. We also know that they have little incentive not to in many areas, because when they do get caught the cost is often much less than their ill-gotten gains.
If you say that incompetence is more common than greed, I might agree with you (depending on the context). However, even if I agreed that the odds - generically speaking - favoured the incompetence explanation, you still need something more substantial than the citation of a foolish meme to dismiss the alternative as unreasonable in any particular case.
Hanlon's Razor begins with "Never...". Now that I called you on it, you have switched to "...usually..." without admitting what you were doing.
Hanlon's Razor has no place in rational discourse, as it assumes an absolute that is known to be false even by those who repeat it - namely, that malice/greed/etc. are very rare and/or always easily distinguished from incompetence.
You are trying to set up a false dichotomy: that one must either accept Hanlon's Razor, or become a cynical (or perhaps wild-eyed?) conspiracy theorist. This is not so; the better alternative is to rationally evaluate the details of each specific case under consideration. If insufficient detail is available, then just admit that you don't know what's going on, instead of trotting out a vacuous meme.
(Notice that I have not commented one way or the other on the truth of the accusation made in the summary.)
Hanlon's Razor applies here as always: never attribute to malice what can be explained by incompetence.
Ah, yes - the Hanlon's Razor argument: this maxim is true because it has a name!
Seriously though, Hanlon's Razor is idiotic. Malice - or more accurately in this case, greed - is extremely common in the real world (as is incompetence). Dismissing the possibility out of hand is bizarre and naive.
If that is true, then it is true because it is the jack that you use far more often than any other type of jack.
Not so. I plug in my phone and (back before the headphone jack broke) my tablet to charge about twice a day. On the other hand, I only plug in my headphones maybe twice a week.
It wears out ridiculously fast. I've had to find the "sweet spot" on an untold number of 3.5mm jacks. You either have to twist the plug to the perfect angle or apply pressure on the correct side, or else you get no sound or severely diminished sound.
This has been my experience as well. Not every jack fails - but it still happens more often than for any other jack type that I commonly use. However, I'm still not happy about the move to USB (or Lightning) for everything.
Why? Because manufacturers are cheaping out by actually removing the headphone jack, rather than replacing it. If everything plugs in by USB, good - but I still need to be able to plug in more than one thing at a time, and no I don't want to add a bulky hub to do it.
But there is a small group of hard core right wingers who just can't get out of the 19th century, they'll all die off from old age soon enough...
I'm 28 years old, and have many friends around the same age. We are not Republicans (nor Democrats), but we still care about the Law of God which was revealed to man a long, long time before the 19th century. Our people have weathered worse storms than this in the past, and we will remain long after yours are forgotten.
"But the heavens and the earth which are now preserved by the same word, are reserved for fire until the day of judgment and perdition of ungodly men. But, beloved, do not forget this one thing, that with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance." - The Apostle Peter, circa 65 A.D.
Similarly, Falcon has second stage which is toasted, a recovered first stage which needs rework and the Dragon is theoretically about as reusable as the shuttle. Not too different abstractly, but arguably a better architecture.
The most important difference between the SpaceX system versus the Space Shuttle, is that SpaceX designed theirs for what it will actually be used for: moving people and a modest amount of cargo to and from LEO. The Shuttle was a horrific waste of money because it combined too many functions into one: crew launch, temporary space station, science lab, satellite launch, and satellite recovery.
That last one dominated the entire design, and pretty much ruined any possibility of economical operation all by itself. It was driven by the military, not NASA. The irony is, I don't think they ever even used it...
It's a matter of numbers. If 5% of pet dogs went rabid, owning dogs would be outlawed.
There are two reason that rabies isn't a big problem with dogs (in the developed world, at least):
1) Any dog that is discovered to be infected is generally killed immediately, before it can spread the disease further. 2) Vaccinations are mandatory and reasonably effective.
Good luck at convincing all the dog owners around the place that their pets should die too:)
Good luck vaccinating hundreds of thousands of wild bats.
According to the National Geographic link at the end of the summary, only5% of bats are infected. So there's really nothing to worry about: in a typical large colony with many thousands of individuals, only thousands of them carry rabies./s
Seriously though - I am not anti-bat, or anti-wildlife in general, but it's pretty obvious that some of the more rabid Greens are willing to say whatever it takes to portray all wild animals as good neighbours, no matter how dangerous their deception is to fellow humans. (Another disturbing example of this being the way that many people insist that large predators - lions, bears, wolves, etc. - never attack humans, except by accident, or in defence of their young - despite thousands of years of evidence to the contrary.)
There are often (although certainly not always) good reasons that our ancestors wiped out the local populations of various pests and predators. A rational society should thoughtfully weigh the pros and cons of reintroducing them into populated areas, rather than committing the game management equivalent of alternative medicine's "natural = good" fallacy.
A floating colony on Venus is quite doable with today's technology.
Venus would make some things easier, like solar power generation. It would also make some things harder, like mining metals. Either way, choosing that location does not solve the hardest problems for true space colonization: long-term life support independent of Earth (including food, medicine, and pest control) and recreating Earth's gigantic, elaborate industrial supply chains from scratch.
The life support problem (think ecosystems, not air scrubbers) is, at this moment, completely unsolved and very poorly understood. The supply chain problem has one known solution - the present-day global economy, which is far too big to launch into space. Both of those problems may well be solved - eventually - with enough research and development. But, by definition, the result will not be "today's technology". Wake me when we have self-sustaining cloud cities on Earth; then we can talk about how we're going to put them on Venus.
I suppose you prefer to starve to death here... With the population growth plus global warming issues there will be NO where to live.
It's economically impossible to relieve population pressure on Earth via space with current propulsion technology. For every one person launched in to space, thousands (millions?) more must stay on Earth building and operating space launchers. This is just a waste of resources that could have been spent on developing better technological solutions to the various problems at hand.
Moreover, there is nowhere to send those people, since the technology to sustain life - let alone duplicate the world economy - on another planet does not currently exist. Right now, sending people to permanently live in space either means killing them (perhaps slowly), or committing to support them in a fashion that is thousands of times more expensive than if they had just stayed on Earth.
These problems might eventually be overcome through improved technology - or they might not. If they can be overcome, it is virtually guaranteed that the same technology will also be used to massively increase the carrying capacity of the Earth, which is naturally compatible with human life - unlike Mars, or any other known candidate for colonization.
Cleaning junk may be necessary to prevent Kessler Syndrome from taking off. That's worth spending quite a lot of money on, depending on which orbits are threatened: space-based navigation (GPS), communications, and earth observation (weather, military surveillance, Google maps) are extremely valuable to the global economy.
Almost all of the other proposed justifications for investing in space infrastructure are either bogus or over-valued though, in my opinion:
- Exploring moons and other planets has some value, but nowhere near enough to justify the current insane expense of sending people.
- Mining anything less easily accessible or less value-dense than a near-Earth asteroid made mostly of gold looks to be a net negative: the more space mining we do, the poorer we'll become.
- Self-sustaining colonies built on current technology are pure fantasy. Trying to support even a single large colony via supplies from Earth would probably bankrupt the world.
Economically useful exploitation of deep space will most likely require some combination of dramatic improvements in propulsion technology, Von Neumann machines (robots that can build copies of themselves out of mass which is 99.9+ % collected automatically from the extraterrestrial environment), and closed-loop life support systems. I'm not discounting the possibility of any of those things, but if people really want to live on Mars or whatever, the sane way to pursue that right now is to invest in such game-changing technologies - not to spend endless billions on inherently inadequate schemes based on shipping everything from Earth using absurdly large chemical rockets.
There are a couple of problems with relying on jury nullification:
1) The average person doesn't know it's an option, and most judges won't let anyone tell them during the case.
2) One of the key purposes of the modern American jury selection process is to filter out anyone who might think for themselves.
Slashdot Mirror
Perhaps the median would be better; I'm not especially well versed in statistics. I don't think it would effect the point I'm making in this case, though.
If you disagree, I'd be interested to see you provide some example calculations demonstrating why. The choice is kind of arbitrary, regardless.
an internal combustion engine - as used in a petrol-driven vehicle - gets around 20% efficiency
Actually, the engines themselves are 30% to 40% efficient on modern gasoline-powered cars. There are some additional losses in the transmission, which is something like 95 to 98% efficient. Running outside the optimal load range also makes the engine a lot less efficient, but that's only relevant in stop-and-go traffic, and hybrid electric systems largely solve the issue. Even non-hybrid cars do a lot better in this respect than they used to, by automatically stopping and starting the engine at lights, and having more gears.
The efficiency of the complete drivetrain of a new ICE vehicle is 20% (standard) to 35% (efficient hybrid) for stop-and-go, and considerably better on the highway.
That's 6.189km per kWh, or about 162 grams of carbon dioxide of emissions - using worst case carbon generation - per km travelled.
Electric cars aren't 100% efficient, either; total up the losses in charging and discharging (86% efficient), power conversion (97%), and the motor(s) themselves (91%), and the total efficiency of the drive train is more like 76%.
An electric car? The infrastructure is already in place; there is negligible marginal cost in getting the power from the plant to the car.
That's not true. Even in the USA, grid transmission is only about 94% efficient. (It's much worse in developing countries; for India it's estimated at 70%. The huge difference is because building and maintaining reliable, efficient power transmission and distribution is not cheap, and some places are too poor to do it well.)
So best case, with a diesel S-class vehicle, you're about one third better than the Model S; worst case (5+ litre petrol engine), you're 50% worse.
We must adjust your 162 g/km estimate upward by 40% to account for the EV inefficiencies that you ignored, which gives us a revised estimate of 227 g/km - worse than all but the most over-powered of the four Mercedes models found in the document that you linked.
Another factor to consider as well is the cost of transporting the fuel: trucks have to carry that fuel (diesel, petrol, etc.) to the station, and you have to drive to the station to refuel.
You can't pretend this is a useful or fair comparison if you only consider the supply chain for the contents of the ICE car's gas tank, and ignore everything else. Mining and moving coal has a substantial environmental and economic impact as well. So does mining Lithium for batteries, or refining and doping Silicon for solar panels, etc.
There are really only two reasonable ways to estimate the true environmental impact of a product:
1) Start from nothing but labour and raw natural resources (think minerals still in the ground, not steel) and work your way up every stage of the production, supply, and maintenance chain - you can't assume trains are moving coal, until you've figured out the full impact of making and running trains from scratch.
2) Or, assume that the selling price of an item already accounts for its environmental impact (partially true).
(1) is probably more accurate, but if you're going to do it you need to do it for everything, or at least apply
Tesla M 3 start at the average price of a sold car in America
No. The average price of a car sold in America is about $22,000, whereas the Tesla Model 3 starts at $35,000.
The average new car purchase costs $33,560. However, 69% of cars sold are used with an average price of $16,800, because most people can't really afford to buy new. Furthermore, those numbers are probably the arithmetic mean, whereas the geometric mean (surely a lower number) would probably be more useful.
Anecdotally, the geometric mean price of a car purchase among my own social circles (which encompass everything from the intermittently homeless up to the beginning of the upper class) is definitely MUCH less than $35,000, with a strong majority of the vehicles purchased being used. Anyone who thinks a $35,000 car is affordable to the average American adult is out-of-touch with the true economic condition of the general population.
Some used 2017 Teslas might reach affordability for regular people in five years or so - or they might not; nobody knows for sure what the maintenance requirements and depreciation rate for the Model 3 will be like, yet.
Covering a habitat in space rocks as extra shielding is sensible, as long as you don't need to change your trajectory while taking the extra shielding with you.
However, I don't think NASA has any zero-g activities planned for the foreseeable future which meet that criteria, and even if they did it would probably be much cheaper and safer to just bring some empty bags with them, instead of trying to fabricate them out of asteroid glass in space. Making things during the mission only really makes sense if it's really easy and you need tons of the stuff (like water, oxygen, hydrogen, and maybe methane or ammonia).
Non-trivial space/extra-terrestrial manufacturing is unlikely to pay for itself unless and until mankind's activities grow beyond the level of the occasional tiny research mission. The contract discussed in the article is part of NASA's efforts to figure out how to send more tiny research missions beyond LEO, and has nothing to do (directly) with a hypothetical sci-fi colonization effort.
... cool very slowly ... annealing ... foot or two thick ... best to have two layers and run, say, paraffin (US meaning) in between ... volatiles go off with the pre-heating (and are collected separately, because there are as valuable as the rest)
All of that makes sense, and would probably help a ton - but, it also makes the whole process a lot more complex than the AC's proposal, and majorly ups the required equipment and technology level. It could be useful to a hypothetical far-future colonization project, but would certainly be far more trouble than it was worth for any of NASA's planned activities over the next few decades.
The subject of the article, and my reply, was NASA, an organization which currently has no mandate or funding for establishing random asteroid bases in the middle of nowhere. They are, however, theoretically working towards a manned Mars - or maybe Moon - mission, which will require habitats light enough to economically move around.
Even if they were commissioned to build a habitat on some random asteroid, the proposed glass bubble doesn't actually help with that unless it can be made strong and airtight very easily (meaning, using less launch mass and research funding than just sending a hull from Earth). Better to just ship out a high-tech inflatable habitat or something, and maybe cover it with raw space rock/dust/ice for extra shielding from radiation and micro meteorites.
Use big mirrors and sunlight to heat space rock until it goes lava. Then blow gas inside the molten blob until it is big enough for your needs. Let it cool down, add holes for doors and windows.
Glass is brittle and tends to fracture. Don't expect junky mystery glass to hold up well long-term against micro-meteorite impacts - especially if it's made thin enough not to crack right away from thermal contraction during the cooling process. Cracks = leaks.
Even if it turned out to be practical to make something truly airtight via your technique, the result would still be super heavy compared to the high-tech alternatives favoured by the space industry: even homogeneous, high-quality synthetic glass has a poor strength-to-mass ratio as compared to structural metals (aluminium, steel, titanium) or synthetic fibres (kevlar, carbon fibre, etc.).
NASA wants maximum reliability (for both political and moral reasons) and minimum weight, because the cost of sending even lightweight manned spacecraft to Mars and back is already more than they can actually afford. What problem does melting space rocks solve for them?
Unlike Australis, Classic Theme Restorer is very configurable and allows elements from the new and the old theme to be mixed-and-matched freely. Visually, I am using the new theme, but I use Classic Theme Restorer to tweak various small things about it for better usability.
Also, imagine a line of people standing single-file, extending infinitely in both directions. There are, of course, an infinite number of people. Now, imagine each of these people is joined by a partner. Are there twice as many people now? Does this mean there are "2 x infinity" people? But surely you can't do that to infinity. Er...
Spoiler; I'm not a mathematician, and don't have the answers, I'm just throwing this out here for amusement. Though I guess someone who knows more about this than I do could explain it
Modern mathematics recognizes the existence of different "sizes" of infinity, but they don't follow the standard rules of arithmetic. The basic idea is not complicated: anyone who can grasp intermediate algebra should be able to understand it, eventually. (I'm sure that my explanation won't be good enough for a lot of people though; try searching YouTube for "Hillbert's Hotel paradox", maybe.)
However, the infinite is far outside our everyday experience, so a bit of vocabulary from higher math will make it a lot easier to discuss the examples which follow:
set - an unordered collection of unique elements. Elements can be numbers, names, other sets, or whatever. Duplicate elements are not allowed: the number 53 (for example) is either in a particular set, or it is not; the set cannot contain two "copies" of 53, or anything like that.
cardinality - this is the "size" of a set. Two sets have the same cardinality if and only if their members can be put in one-to-one correspondence. For sets with a finite number of elements, such as the set of letters in the English alphabet, the cardinality is simply the number of elements in the set: 26, in this case. This is easily proven by simply associating a number with each letter (A => 1, B => 2, C => 3, ...).
Where things get interesting, is when we try to compare the sizes of two infinite sets, such as the set of all even numbers (0, 2, 4, 6, ...) versus the set of all whole numbers (0, 1, 2, 3, 4, ...). We cannot simply count the number of elements using finite whole numbers. Instead, we must use transfinite cardinal numbers. To understand what those are, consider some classic examples:
Hillbert's Paradox of the Grand Hotel ...
Imagine that Hillbert's Hotel has an infinite number of rooms, every one of which is occupied by exactly one person. The rooms are each numbered with a sign on the door: 1, 2, 3, 4,
Question: A new guest arrives, and asks the host for a private room. Can the host provide him with a room without doubling anyone up, or kicking anyone out of the hotel?
Answer: Surprisingly, yes he can! Here's one way he could do so: the host gets on the public address system and instructs every guest to pack his bags, leave his room, look at the number on the door, add one to it, and move into the room with that new number. So, the guy in room #1 moves into #2, the guy in #2 moves into #3, and so on.
At a finite hotel, this could never work: whoever was in the last room would be kicked out, with no higher numbered room to move into. However, in Hillbert's infinite hotel there is no last room, and so there is no problem. Everyone moves over by one room, and the new guest moves into room #1.
Conclusion: infinity + 1 = infinity.
Question: Suppose that the neighbouring Cantor's Infinite Hotel (same setup) needs to be fumigated (or nuked from orbit) because it is infested with an infinite number of cockroaches. The manager of Cantor's Hotel asks the host of Hilbert's Hotel if he can temporarily accommodate an infinite crowd of additio
Are you too incompetent to copy-and-paste, or do I detect a wee bit of malice in the way that you misquoted me?
The point of Hanlon's razor is that it's a good life strategy.
Deliberately putting one's head in the sand is not a good life strategy.
Feeling that someone's out to get you, especially when there's nothing you can really do about it, will not make you more happy.
Who told you that "there's nothing you can really do about it"? Incompetence and malice call for different responses, and thus attempting to distinguish between them is useful.
When a business sends me incorrect bills by accident, I should correct the error and double-check their figures in the future. If such errors occur frequently, I should politely complain to management and encourage them to figure out why their billing process is so flaky, and fix it. This action is helpful to myself, the business, and their other customers: honest mistakes don't necessarily favour one party over the other; they just sow confusion and it is in everyone's interest to prevent them if reasonably possible.
When a business defrauds me on purpose, I should end my relationship with them as soon as possible, and/or threaten legal action. Otherwise they'll just keep looking for ways to cheat me - possibly a way that I'm not clever enough to spot, next time.
Neither of those approaches is useless, but matching the approach to the situation is important - but Hanlon's Razor would prevent me from even trying most of the time.
Bah, enough with the penerdandtry.
It's not pedantry; if you read what I wrote more carefully you'll see that it does not depend upon a literal definition of "never". (Unless you insist upon committing the same error in interpreting my words, which you accuse me of committing with yours.)
However, "usually" and "always" are still very different words even allowing for the normal imprecision of humans speech: "usually" simply means "more than half the time", whereas "always" means "an overwhelming majority of the time".
It is simply not true that malice/greed is so rare that its occurrence can reasonably be ignored by default, and you know it. Society has rules, judges, and enforcers (not just talking about the government here - think parents, teachers, sports referees, etc. too) for a reason: because people lie, cheat, and steal quite frequently - especially when they think they can get away with it.
Big businesses break the rules all the time, often intentionally. We know this because they get caught sometimes. We also know that they have little incentive not to in many areas, because when they do get caught the cost is often much less than their ill-gotten gains.
If you say that incompetence is more common than greed, I might agree with you (depending on the context). However, even if I agreed that the odds - generically speaking - favoured the incompetence explanation, you still need something more substantial than the citation of a foolish meme to dismiss the alternative as unreasonable in any particular case.
Hanlon's Razor begins with "Never...". Now that I called you on it, you have switched to "...usually..." without admitting what you were doing.
Hanlon's Razor has no place in rational discourse, as it assumes an absolute that is known to be false even by those who repeat it - namely, that malice/greed/etc. are very rare and/or always easily distinguished from incompetence.
You are trying to set up a false dichotomy: that one must either accept Hanlon's Razor, or become a cynical (or perhaps wild-eyed?) conspiracy theorist. This is not so; the better alternative is to rationally evaluate the details of each specific case under consideration. If insufficient detail is available, then just admit that you don't know what's going on, instead of trotting out a vacuous meme.
(Notice that I have not commented one way or the other on the truth of the accusation made in the summary.)
Hanlon's Razor applies here as always: never attribute to malice what can be explained by incompetence.
Ah, yes - the Hanlon's Razor argument: this maxim is true because it has a name!
Seriously though, Hanlon's Razor is idiotic. Malice - or more accurately in this case, greed - is extremely common in the real world (as is incompetence). Dismissing the possibility out of hand is bizarre and naive.
If that is true, then it is true because it is the jack that you use far more often than any other type of jack.
Not so. I plug in my phone and (back before the headphone jack broke) my tablet to charge about twice a day. On the other hand, I only plug in my headphones maybe twice a week.
It wears out ridiculously fast. I've had to find the "sweet spot" on an untold number of 3.5mm jacks. You either have to twist the plug to the perfect angle or apply pressure on the correct side, or else you get no sound or severely diminished sound.
This has been my experience as well. Not every jack fails - but it still happens more often than for any other jack type that I commonly use. However, I'm still not happy about the move to USB (or Lightning) for everything.
Why? Because manufacturers are cheaping out by actually removing the headphone jack, rather than replacing it. If everything plugs in by USB, good - but I still need to be able to plug in more than one thing at a time, and no I don't want to add a bulky hub to do it.
But there is a small group of hard core right wingers who just can't get out of the 19th century, they'll all die off from old age soon enough...
I'm 28 years old, and have many friends around the same age. We are not Republicans (nor Democrats), but we still care about the Law of God which was revealed to man a long, long time before the 19th century. Our people have weathered worse storms than this in the past, and we will remain long after yours are forgotten.
"Heaven and earth shall pass away, but my words shall not pass away." - The Lord Jesus Christ, circa 30 A.D.
"But the heavens and the earth which are now preserved by the same word, are reserved for fire until the day of judgment and perdition of ungodly men. But, beloved, do not forget this one thing, that with the Lord one day is as a thousand years, and a thousand years as one day. The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance." - The Apostle Peter, circa 65 A.D.
Similarly, Falcon has second stage which is toasted, a recovered first stage which needs rework and the Dragon is theoretically about as reusable as the shuttle. Not too different abstractly, but arguably a better architecture.
The most important difference between the SpaceX system versus the Space Shuttle, is that SpaceX designed theirs for what it will actually be used for: moving people and a modest amount of cargo to and from LEO. The Shuttle was a horrific waste of money because it combined too many functions into one: crew launch, temporary space station, science lab, satellite launch, and satellite recovery.
That last one dominated the entire design, and pretty much ruined any possibility of economical operation all by itself. It was driven by the military, not NASA. The irony is, I don't think they ever even used it...
it would be neither
I am using the golden standard of American science: 100 yards from goal line to goal line, without the end zones.
an American football pitch is 120 yards long.
In America, we have the liberty to throw balls as short or long of a distance as we like. It makes our games (like baseball) much more interesting.
What's a mile?
It's a unit of length equal to 17.6 football fields.
It's a matter of numbers. If 5% of pet dogs went rabid, owning dogs would be outlawed.
There are two reason that rabies isn't a big problem with dogs (in the developed world, at least):
1) Any dog that is discovered to be infected is generally killed immediately, before it can spread the disease further.
2) Vaccinations are mandatory and reasonably effective.
Good luck at convincing all the dog owners around the place that their pets should die too :)
Good luck vaccinating hundreds of thousands of wild bats.
According to the National Geographic link at the end of the summary, only 5% of bats are infected. So there's really nothing to worry about: in a typical large colony with many thousands of individuals, only thousands of them carry rabies. /s
Seriously though - I am not anti-bat, or anti-wildlife in general, but it's pretty obvious that some of the more rabid Greens are willing to say whatever it takes to portray all wild animals as good neighbours, no matter how dangerous their deception is to fellow humans. (Another disturbing example of this being the way that many people insist that large predators - lions, bears, wolves, etc. - never attack humans, except by accident, or in defence of their young - despite thousands of years of evidence to the contrary.)
There are often (although certainly not always) good reasons that our ancestors wiped out the local populations of various pests and predators. A rational society should thoughtfully weigh the pros and cons of reintroducing them into populated areas, rather than committing the game management equivalent of alternative medicine's "natural = good" fallacy.
A floating colony on Venus is quite doable with today's technology.
Venus would make some things easier, like solar power generation. It would also make some things harder, like mining metals. Either way, choosing that location does not solve the hardest problems for true space colonization: long-term life support independent of Earth (including food, medicine, and pest control) and recreating Earth's gigantic, elaborate industrial supply chains from scratch.
The life support problem (think ecosystems, not air scrubbers) is, at this moment, completely unsolved and very poorly understood. The supply chain problem has one known solution - the present-day global economy, which is far too big to launch into space. Both of those problems may well be solved - eventually - with enough research and development. But, by definition, the result will not be "today's technology". Wake me when we have self-sustaining cloud cities on Earth; then we can talk about how we're going to put them on Venus.
I suppose you prefer to starve to death here... With the population growth plus global warming issues there will be NO where to live.
It's economically impossible to relieve population pressure on Earth via space with current propulsion technology. For every one person launched in to space, thousands (millions?) more must stay on Earth building and operating space launchers. This is just a waste of resources that could have been spent on developing better technological solutions to the various problems at hand.
Moreover, there is nowhere to send those people, since the technology to sustain life - let alone duplicate the world economy - on another planet does not currently exist. Right now, sending people to permanently live in space either means killing them (perhaps slowly), or committing to support them in a fashion that is thousands of times more expensive than if they had just stayed on Earth.
These problems might eventually be overcome through improved technology - or they might not. If they can be overcome, it is virtually guaranteed that the same technology will also be used to massively increase the carrying capacity of the Earth, which is naturally compatible with human life - unlike Mars, or any other known candidate for colonization.
Cleaning junk makes no profit
Cleaning junk may be necessary to prevent Kessler Syndrome from taking off. That's worth spending quite a lot of money on, depending on which orbits are threatened: space-based navigation (GPS), communications, and earth observation (weather, military surveillance, Google maps) are extremely valuable to the global economy.
Almost all of the other proposed justifications for investing in space infrastructure are either bogus or over-valued though, in my opinion:
- Exploring moons and other planets has some value, but nowhere near enough to justify the current insane expense of sending people.
- Mining anything less easily accessible or less value-dense than a near-Earth asteroid made mostly of gold looks to be a net negative: the more space mining we do, the poorer we'll become.
- Self-sustaining colonies built on current technology are pure fantasy. Trying to support even a single large colony via supplies from Earth would probably bankrupt the world.
Economically useful exploitation of deep space will most likely require some combination of dramatic improvements in propulsion technology, Von Neumann machines (robots that can build copies of themselves out of mass which is 99.9+ % collected automatically from the extraterrestrial environment), and closed-loop life support systems. I'm not discounting the possibility of any of those things, but if people really want to live on Mars or whatever, the sane way to pursue that right now is to invest in such game-changing technologies - not to spend endless billions on inherently inadequate schemes based on shipping everything from Earth using absurdly large chemical rockets.
There are a couple of problems with relying on jury nullification:
1) The average person doesn't know it's an option, and most judges won't let anyone tell them during the case.
2) One of the key purposes of the modern American jury selection process is to filter out anyone who might think for themselves.