Solar and wind power generation by themselves don't reduce the amount of peak power production capacity by other means necessary, since peak demand can coincide with times with no sun or wind. However, if an energy storage media is available, then all power needs can be met by just enough solar and wind capacity to meet _average_ demand -- which is significantly lower than peak demand. I always imagined pumping water uphill into a reservoir to feed hydroelectric turbines as a way of storing power, but if batteries really become cheap and reliable... I'll take whatever works.
In the bigger picture we should be using high voltage DC lines, a proven 80 year old commercial technology, to ship power long distances so that peak demand cannot coincide with times with no sun or wind since the sun and wind resources of the entire continent is connected together. It never happens that no sun and wind is found anywhere.
And by the same token pumped water storage can be used for the entire national grid, not matter where the storage is.
With a properly implemented national grid the use of batteries should be pretty small.
Peakers can - and sometimes do (especially in Southern California) run for days on end. How big of a battery do you need to support that?
CItation needed. You are describing yet another type of plant - a load following plant that comes on line for a period of up to days during periods of high demand. In California the most efficent combined-cycle gas plants are used for this, not peaker plants. More precisely CC plants are used for load following by throttling their output up and down. They are never idle.
It is fallacy to argue that some corner cases exist where this will not work (as well) to assert that the entire approach is flawed.
In the asteroid belt alone, there's a ton of potentially valuable materials to mine. It wouldn't take much advancement from our current technology to send ships there to identify good targets, mine the asteroids, and then bring the materials back to Earth. Yes, it will be very dangerous, but the possibility of untold riches will drive people to risk their lives.
"Untold riches"? This is either hype or fiction. It be better to tell of the riches. Currently the richest space resource identified by science is platinum group metals (PGM) in certain types of asteroids. The total value of these comes to $3/kg of asteroid in the richest type. It would take radical advancement in technology to be able to retrieve such asteroid material profitably, and processing the ore in space is far harder.
The entire world PGM market demand is $40 billion a year and represents an effective ceiling on the value of space mining for this resource. Sure if you could do it for less than what it costs on Earth (i.e. reduce the value of that ore to below $3/kg), you could expand the use of these metals, but that does not mean that the size of the market would expand appreciably, in fact there are solid economic reasons to think that would not occur.
Top put this in perspective the value of the global satellite industry is $260 billion a year. So automated space operations currently far exceed the prospective value of the most plausible asteroid mining scenario.
(Yes, much of this could be done with robots, but a human on board would be valuable for making on the spot judgement calls.)
We have yet to ever see a case in space exploration where this is true. This is the sort of claim that was common in the 1960s before we had much (or any) of an experience base. It is an unsustainable claim today.
What sort of judgement calls cannot be made from Earth using the exact same sensor data the human-on-board would be using? We can use sophisticated software to conduct "real-time" operations (with response times far faster than sluggish humans), and a one hour round trip for human consideration is not really a problem.
Pointing out essential hard facts is not "lack of imagination". Imagination is grand, but it needs to be coupled to what is feasible.
It is common in SF to make a parallel with the Age of Exploration (by Europeans), or possibly prehistoric oceanic colonization of lands, and space exploration. But in neither case were the 'costs' to the parent society consistently negative. Exploration voyages and settlement were expected to turn a profit, and did fairly quickly. Prehistoric colonization cost parent societies nothing (in fact ridding themselves of surplus population may have been a key driver).
All humans-in-space exploration is a pure loss economically, and it is not even an effective way to do science. How much can we spend on symbolism alone?
They could sustain accelerations in swing-by maneuvers no human would survive.
Others point out that swing-by maneuvers are free-fall, but there is another reason there is a limitation for this with humans. The radiation field of Jupiter. The probes that used sling-shot maneuvers with Jupiter experienced many times lethal levels of radiation exposure. And long-term radiation exposure in space is a problem anyway.
Or is it that it's very expensive and extremely dangerous?
Especially the "expensive" part.
It is notable that the article mentions "money" only once, to brush it away as irrelevant ('Not know-how, or even money').
The cost of space travel, in other words the relative share of Earth productive resources, required is staggering for many reasons. Slashing launch costs still leaves those costs at "staggering" (though a smaller stagger), and does not touch the other costs - the extremely high cost of space hardware, the ground support required, etc.
Couple that with the point it does bring up - what is the actual value of putting humans there in practical terms? - and the reasons for the 'failure' to do more than what we are doing (we do have the ISS in space, which isn't nothing) are obvious, and compelling.
The cost relative to the value returned is crucially important.
The current cost of keeping one person in space is about one billion dollars per year. Launch costs are an important of that, but they are not overwhelming dominant. Slashing the launch cost still leaves manned spaceflight as extremely expensive, hundreds of millions a year per person. Only very limited operations can ever be supported at present.
We need to have far more advanced technology, and much higher economic productivity, for space flight to be affordable for more than an occasional few leaving Earth.
Something about the OP doesn't make sense.
And no, not the fact that there isn't much in the way of "high-pressure air" at the outermost fringes of our atmosphere...
The part which seems a little odd is to suggest that altering the apparent pressure [i.e. by the velocity of entry] can in some way "force" air into the cracks within a meteorite/meteorid to induce some form of break-up.
Isn't it much more likely to be induced by the coefficient of expansion of the material concerned? If you take a meteorite and then flash-heat the outer surface very, very, very quickly - like for example by slamming it into an atmosphere at several thousand kph - then the outer layer will become very, very hot very quickly - and start to expand. The interior, meanwhile, simply won't have had time to warm up and thus will remain space-cold... As the outer layer warms, it expands. This would easily be enough to cause cracks in the material [think of the way that you can split a rock by pouring water into a crack and then waiting for the water to freeze...].
It's been a while since I studied CFD [computational fluid dynamics - which is the science that would show how atmospheric gases would "flow" around an meteorite as it entered the atmosphere - but I think it's fair to say that a "boundary layer" would form that might in fact make it ridiculously difficult for "high pressure air" to be "forced" into tiny cracks in the surface.
Interesting how you imagine tossing around some dimly remembered terms like "boundary layer" invalidates the detailed physics of these researcher's model.
If they had access to your brilliance they would have know the answer without even examining the problem!
This should a Slashdot "law":
"If, with just a few minutes of thought about a scientific topic you have only slight familiarity with, you believe you have identified a fatal error that a team of highly trained professional researchers have failed to detect, you can be certain that you are wrong."
The actual article linked to, and the original paper do not support the claim there is "real value in the resources of our moon". In fact the real situation is summed up by "..the overall case for any future payoff from exploiting the moon's resources has yet to be made, Crawford said." In other words, there is of yet no evidence of real value in the resources of the Moon. In his paper Crawford state flat out that he is not proposing looking for resources to use here on Earth. In other words these are resources for some future space civilization.
When we actually have this space civilization to provide demand, then we can talk.
He does mention, in passing "platinum group metals" as a possible resource for use on Earth, but provides no analysis of this at all. This really does not hold up if you just look at a few numbers. The notion is that one would mine asteroid bodies that crashed into the moon. The problem is the very low value of asteroids as PGM ore. The concentration of PGMs is about 10 times higher than the ores being mined on Earth, but the actual value of the PGM content of the ore of even the best types is only $3/kg. The idea that this is a plausible mining operation that can dig up and ship rocks to Earth at a profit at a value of $3/kg is ludicrous.
You can survey all the literature of space mining without finding anyone making an actual case based on the cost of real mining operations (a least I have never found any and I have looked).
But if, for a far more realistic example, the island had 1 billion units of resources that cost 10 billion units to extract then "staking a claim" would accomplish nothing, except possibly as the basis of a scam to sell worthless shares in the venture.
If Trump/Pai stick to the free market dogma and also outlaw local governments from granting service monopolies, then net neutrality isn't needed.
Outlawing local monopolies would help some (although how this can be legally implemented I am unsure of - I am sure that Trump/Pai can't do it) but would hardly eliminate the need.
There all kinds of ways of preventing competition for the local distribution system (the pole access restrictions on Google requiring them to get their competitor to agree to perform service...). But most important is the high cost of entry.
It is economically infeasible for many competitors to lay down fiber - it is a 'natural monopoly'. We need laws and regulations that require open access to a single fiber network, just like we have common access to roads. Geometry makes the idea of competing companies building competing private roads to everyone's homes obviously ridiculous, but economically the situation for fiber isn't much different.
It's not that cells run out of steam ~114, it's that nothing is designed to last that long. So once you're past 110 it doesn't matter if you fix 5 potentially fatal things because 10 others are about to break.
Does anyone here know the poem "The Deacon’s Masterpiece or, the Wonderful "One-hoss Shay": A Logical Story" by Oliver Weldell Holmes? It recounts the story of a superbly constructed One-Horse Shay, that is built so as to have no weak spot and begins:
Have you heard of the wonderful one-hoss shay,
That was built in such a logical way
It ran a hundred years to a day,
And then, of a sudden, it — ah, but stay,
I’ll tell you what happened without delay, ...
Continuing:
Colts grew horses, beards turned gray,
Deacon and deaconess dropped away,
Children and grandchildren — where were they?
But there stood the stout old one-hoss shay
As fresh as on Lisbon-earthquake-day!
And concluding:
Close by the meet’n’-house on the hill.
First a shiver, and then a thrill,
Then something decidedly like a spill, —
And the parson was sitting upon a rock,
At half past nine by the meet’n-house clock, —
Just the hour of the Earthquake shock!
What do you think the parson found,
When he got up and stared around?
The poor old chaise in a heap or mound,
As if it had been to the mill and ground!
You see, of course, if you’re not a dunce,
How it went to pieces all at once, —
All at once, and nothing first, —
Just as bubbles do when they burst.
So you have *no* disproof of Eratosthenes -- only unproved assumptions of a far more complicated model which do not even bother to explicate in detail or show evidence of. Good to know.
Sorry, appealing to special hidden laws thrown in as needed to prop up your refusal to accept simple evidence is a flaming failure.
Most of the world has reached fertility rates that will eventually, over the next several decades, populations will stop growing and begin to decrease. The population of Asia will stabilize and start to decrease around 2055. So for the Americas and Eurasia, and Oceania the problem is solved.
There is one remaining continent where this has not happened yet - the poorest and most underdeveloped continent which is Africa.
So things look grim for Africa, especially sub-Saharan Africa, at present. But the fact that fertility rates have not declined yet does not mean they won't - in fact there is solid reason to think it will start to decline in the next decade. African per capita GDP is growing rapidly (from a low base of course) in the range of 5-6% per year. Over the next few decades we should see a turn-around in Africa as it catches up economically. In much of the world where rates are below replacement now, they did not start to decline until the 1970s and 1980s.
Contrast that to the US where Libertarian principles are at the helm, the best tax package in history for US citizens is about to get passed, the US stock market is at its highest ever, and there is full employment.
Lets see - a minimum trillion dollar increase in the deficit - solid Libertarian principle there! And the Tax Policy Center finds that the richest 1 percent of Americans would reap 48% of the benefits (they pay 36% of Federal taxes). Yep. That sounds Libertarian alright.
Oddly, 10 months ago when it was those lousy Socialist principles at the helm, we also had the highest U.S. stock market ever, and full employment.
The number of young farmers entering the field is nowhere near enough to replace the number exiting, according to the USDA: Between 2007 and 2012, agriculture gained 2,384 farmers between ages 25 and 34 — and lost nearly 100,000 between 45 and 54.
So the number may be increasing, as opposed to decreasing, as it has over the last 70 years, but the number is tiny. Over a five year period the number was 2384, or about 475 per year, (there are about 2 million farmers in the U.S.) and only 2% of the number of U.S. farmers leaving the business during the same period.
Adding 0.1% to the U.S. farm population over five years, during which time it actually lost 5% of its famers, is insignificant.
All of the listed reasons for the drying up a pool of young illegal-immigrant farm workers for those Trump-voting farmers to illegally employ for profit are valid.
The birth rate in Mexico is now below the replacement rate, as it is in the U.S.
The average (and median) age of illegal border crossers is 20. So a border-crosser today was born in 1997 when the fertility rate in Mexico had already plunged 60%. So the oversupply of young people willing to give up their society and family to live on the margins in the U.S. has disappeared and is not ever coming back.
China is still a permanent member. It was never kicked off at any time.
What did happen was that the UN switched which government was recognized as representing the state of China. Instead of considering the government of the island of Taiwan as representing the entire nation of China, in 1971 the UN switched to recognizing the government of the entire nation of China, except Taiwan. But there has always been a permanent seat for China.
The current DNA system very likely has advantages over alternate systems, on Earth's environment at least. A system with different chirality (direction of coiling) seems quite possible (indeed, it has been difficult to discover any convincing advantage for the chirality we observe on Earth); a DNA with different nucleotide pairing is another possible variation; and "DNA" is actually part of a complex system which can be modified in different ways. For example the coding for additional/alternate amino acids in proteins, or versions of the replication enzymes not found on Earth; or in the epigenetic regulation of gene expression.
And we have an ancestor system, the RNA coding system, that is part of the DNA system. It is widely believed that an "RNA world" of replication preceded the development of the DNA system (since DNA depended on it), so we know that alternate systems are possible.
Given all the pieces that the DNA system on Earth has, it is a little challenging to believe that a system that developed independently in a different planetary (?) environment would be identical in every respect.
OTOH, if life developed on Mars at least, there is good reason to think that Earth's DNA system did not develop independently of that. It looks like meteor bombardment transportation is efficient enough to contaminate Earth with samples Martian biochemistry, including extremophilic organisms. Getting material from Earth to Mars is much harder.
Genuinely alien biochemistry might be difficult to recognize as life, since our most sensitive tools for detection generally depend on known similarities to Earth biochemistry.
Slashdot Mirror
Solar and wind power generation by themselves don't reduce the amount of peak power production capacity by other means necessary, since peak demand can coincide with times with no sun or wind. However, if an energy storage media is available, then all power needs can be met by just enough solar and wind capacity to meet _average_ demand -- which is significantly lower than peak demand. I always imagined pumping water uphill into a reservoir to feed hydroelectric turbines as a way of storing power, but if batteries really become cheap and reliable... I'll take whatever works.
In the bigger picture we should be using high voltage DC lines, a proven 80 year old commercial technology, to ship power long distances so that peak demand cannot coincide with times with no sun or wind since the sun and wind resources of the entire continent is connected together. It never happens that no sun and wind is found anywhere.
And by the same token pumped water storage can be used for the entire national grid, not matter where the storage is.
With a properly implemented national grid the use of batteries should be pretty small.
Peakers can - and sometimes do (especially in Southern California) run for days on end. How big of a battery do you need to support that?
CItation needed. You are describing yet another type of plant - a load following plant that comes on line for a period of up to days during periods of high demand. In California the most efficent combined-cycle gas plants are used for this, not peaker plants. More precisely CC plants are used for load following by throttling their output up and down. They are never idle.
It is fallacy to argue that some corner cases exist where this will not work (as well) to assert that the entire approach is flawed.
In the asteroid belt alone, there's a ton of potentially valuable materials to mine. It wouldn't take much advancement from our current technology to send ships there to identify good targets, mine the asteroids, and then bring the materials back to Earth. Yes, it will be very dangerous, but the possibility of untold riches will drive people to risk their lives.
"Untold riches"? This is either hype or fiction. It be better to tell of the riches. Currently the richest space resource identified by science is platinum group metals (PGM) in certain types of asteroids. The total value of these comes to $3/kg of asteroid in the richest type. It would take radical advancement in technology to be able to retrieve such asteroid material profitably, and processing the ore in space is far harder.
The entire world PGM market demand is $40 billion a year and represents an effective ceiling on the value of space mining for this resource. Sure if you could do it for less than what it costs on Earth (i.e. reduce the value of that ore to below $3/kg), you could expand the use of these metals, but that does not mean that the size of the market would expand appreciably, in fact there are solid economic reasons to think that would not occur.
Top put this in perspective the value of the global satellite industry is $260 billion a year. So automated space operations currently far exceed the prospective value of the most plausible asteroid mining scenario.
(Yes, much of this could be done with robots, but a human on board would be valuable for making on the spot judgement calls.)
We have yet to ever see a case in space exploration where this is true. This is the sort of claim that was common in the 1960s before we had much (or any) of an experience base. It is an unsustainable claim today.
What sort of judgement calls cannot be made from Earth using the exact same sensor data the human-on-board would be using? We can use sophisticated software to conduct "real-time" operations (with response times far faster than sluggish humans), and a one hour round trip for human consideration is not really a problem.
Pointing out essential hard facts is not "lack of imagination". Imagination is grand, but it needs to be coupled to what is feasible.
It is common in SF to make a parallel with the Age of Exploration (by Europeans), or possibly prehistoric oceanic colonization of lands, and space exploration. But in neither case were the 'costs' to the parent society consistently negative. Exploration voyages and settlement were expected to turn a profit, and did fairly quickly. Prehistoric colonization cost parent societies nothing (in fact ridding themselves of surplus population may have been a key driver).
All humans-in-space exploration is a pure loss economically, and it is not even an effective way to do science. How much can we spend on symbolism alone?
They could sustain accelerations in swing-by maneuvers no human would survive.
Others point out that swing-by maneuvers are free-fall, but there is another reason there is a limitation for this with humans. The radiation field of Jupiter. The probes that used sling-shot maneuvers with Jupiter experienced many times lethal levels of radiation exposure. And long-term radiation exposure in space is a problem anyway.
Or is it that it's very expensive and extremely dangerous?
Especially the "expensive" part.
It is notable that the article mentions "money" only once, to brush it away as irrelevant ('Not know-how, or even money').
The cost of space travel, in other words the relative share of Earth productive resources, required is staggering for many reasons. Slashing launch costs still leaves those costs at "staggering" (though a smaller stagger), and does not touch the other costs - the extremely high cost of space hardware, the ground support required, etc.
Couple that with the point it does bring up - what is the actual value of putting humans there in practical terms? - and the reasons for the 'failure' to do more than what we are doing (we do have the ISS in space, which isn't nothing) are obvious, and compelling.
The cost relative to the value returned is crucially important.
The current cost of keeping one person in space is about one billion dollars per year. Launch costs are an important of that, but they are not overwhelming dominant. Slashing the launch cost still leaves manned spaceflight as extremely expensive, hundreds of millions a year per person. Only very limited operations can ever be supported at present.
We need to have far more advanced technology, and much higher economic productivity, for space flight to be affordable for more than an occasional few leaving Earth.
Kinda not worried about online porn bringing the world to the brink of apocalypse anytime soon with Google using as much power as 1,000 PornHubs!
Ah, a new unit of power measurement. The "PornHub"!
Does that include end zones?
You should get in an argument with other posters here who declare that this conclusion is obviously impossible.
The arrogance of the lazy boy 'scientist'.
Are you always a cunt or is it just when you have anonymity?
The un-self-aware irony in this is priceless.
Something about the OP doesn't make sense. And no, not the fact that there isn't much in the way of "high-pressure air" at the outermost fringes of our atmosphere... The part which seems a little odd is to suggest that altering the apparent pressure [i.e. by the velocity of entry] can in some way "force" air into the cracks within a meteorite/meteorid to induce some form of break-up. Isn't it much more likely to be induced by the coefficient of expansion of the material concerned? If you take a meteorite and then flash-heat the outer surface very, very, very quickly - like for example by slamming it into an atmosphere at several thousand kph - then the outer layer will become very, very hot very quickly - and start to expand. The interior, meanwhile, simply won't have had time to warm up and thus will remain space-cold... As the outer layer warms, it expands. This would easily be enough to cause cracks in the material [think of the way that you can split a rock by pouring water into a crack and then waiting for the water to freeze...]. It's been a while since I studied CFD [computational fluid dynamics - which is the science that would show how atmospheric gases would "flow" around an meteorite as it entered the atmosphere - but I think it's fair to say that a "boundary layer" would form that might in fact make it ridiculously difficult for "high pressure air" to be "forced" into tiny cracks in the surface.
Interesting how you imagine tossing around some dimly remembered terms like "boundary layer" invalidates the detailed physics of these researcher's model.
If they had access to your brilliance they would have know the answer without even examining the problem!
This should a Slashdot "law":
"If, with just a few minutes of thought about a scientific topic you have only slight familiarity with, you believe you have identified a fatal error that a team of highly trained professional researchers have failed to detect, you can be certain that you are wrong."
Rouge One was what gave Princess Leia's (simulated) face that rosy blush.
But cancelling it before we had a working replacement was a stupid in a special order of magnitude.
Because continuing to use a system that has a proven 1.5% chance of killing everyone board is brilliant?
The actual article linked to, and the original paper do not support the claim there is "real value in the resources of our moon". In fact the real situation is summed up by "..the overall case for any future payoff from exploiting the moon's resources has yet to be made, Crawford said." In other words, there is of yet no evidence of real value in the resources of the Moon. In his paper Crawford state flat out that he is not proposing looking for resources to use here on Earth. In other words these are resources for some future space civilization.
When we actually have this space civilization to provide demand, then we can talk.
He does mention, in passing "platinum group metals" as a possible resource for use on Earth, but provides no analysis of this at all. This really does not hold up if you just look at a few numbers. The notion is that one would mine asteroid bodies that crashed into the moon. The problem is the very low value of asteroids as PGM ore. The concentration of PGMs is about 10 times higher than the ores being mined on Earth, but the actual value of the PGM content of the ore of even the best types is only $3/kg. The idea that this is a plausible mining operation that can dig up and ship rocks to Earth at a profit at a value of $3/kg is ludicrous.
You can survey all the literature of space mining without finding anyone making an actual case based on the cost of real mining operations (a least I have never found any and I have looked).
But if, for a far more realistic example, the island had 1 billion units of resources that cost 10 billion units to extract then "staking a claim" would accomplish nothing, except possibly as the basis of a scam to sell worthless shares in the venture.
Sigh. Just a meaningless photo op, and a standard Trump boastful proclamation.
We aren't just going to the Moon, we are going to Mars and "many worlds beyond"!
There is no actual plan, or action involved here. No funding for the big words.
BTW - how is GHW Bush's Space Exploration Initiative going? Are we on Mars yet?
This announcement at least had some actual plans associated with it:
Ah, remember when we accomplished those national milestones?
No?
Of course not a single one of these actually got any funding to even begin actual work on the component of the plan.
If Trump/Pai stick to the free market dogma and also outlaw local governments from granting service monopolies, then net neutrality isn't needed.
Outlawing local monopolies would help some (although how this can be legally implemented I am unsure of - I am sure that Trump/Pai can't do it) but would hardly eliminate the need.
There all kinds of ways of preventing competition for the local distribution system (the pole access restrictions on Google requiring them to get their competitor to agree to perform service...). But most important is the high cost of entry.
It is economically infeasible for many competitors to lay down fiber - it is a 'natural monopoly'. We need laws and regulations that require open access to a single fiber network, just like we have common access to roads. Geometry makes the idea of competing companies building competing private roads to everyone's homes obviously ridiculous, but economically the situation for fiber isn't much different.
It's not that cells run out of steam ~114, it's that nothing is designed to last that long. So once you're past 110 it doesn't matter if you fix 5 potentially fatal things because 10 others are about to break.
Does anyone here know the poem "The Deacon’s Masterpiece or, the Wonderful "One-hoss Shay": A Logical Story" by Oliver Weldell Holmes? It recounts the story of a superbly constructed One-Horse Shay, that is built so as to have no weak spot and begins:
Have you heard of the wonderful one-hoss shay,
...
That was built in such a logical way
It ran a hundred years to a day,
And then, of a sudden, it — ah, but stay,
I’ll tell you what happened without delay,
Continuing:
Colts grew horses, beards turned gray,
Deacon and deaconess dropped away,
Children and grandchildren — where were they?
But there stood the stout old one-hoss shay
As fresh as on Lisbon-earthquake-day!
And concluding:
Close by the meet’n’-house on the hill.
First a shiver, and then a thrill,
Then something decidedly like a spill, —
And the parson was sitting upon a rock,
At half past nine by the meet’n-house clock, —
Just the hour of the Earthquake shock!
What do you think the parson found,
When he got up and stared around?
The poor old chaise in a heap or mound,
As if it had been to the mill and ground!
You see, of course, if you’re not a dunce,
How it went to pieces all at once, —
All at once, and nothing first, —
Just as bubbles do when they burst.
So you have *no* disproof of Eratosthenes -- only unproved assumptions of a far more complicated model which do not even bother to explicate in detail or show evidence of. Good to know.
Sorry, appealing to special hidden laws thrown in as needed to prop up your refusal to accept simple evidence is a flaming failure.
False. World population continues to grow.
Most of the world has reached fertility rates that will eventually, over the next several decades, populations will stop growing and begin to decrease. The population of Asia will stabilize and start to decrease around 2055. So for the Americas and Eurasia, and Oceania the problem is solved.
There is one remaining continent where this has not happened yet - the poorest and most underdeveloped continent which is Africa.
So things look grim for Africa, especially sub-Saharan Africa, at present. But the fact that fertility rates have not declined yet does not mean they won't - in fact there is solid reason to think it will start to decline in the next decade. African per capita GDP is growing rapidly (from a low base of course) in the range of 5-6% per year. Over the next few decades we should see a turn-around in Africa as it catches up economically. In much of the world where rates are below replacement now, they did not start to decline until the 1970s and 1980s.
Contrast that to the US where Libertarian principles are at the helm, the best tax package in history for US citizens is about to get passed, the US stock market is at its highest ever, and there is full employment.
Lets see - a minimum trillion dollar increase in the deficit - solid Libertarian principle there! And the Tax Policy Center finds that the richest 1 percent of Americans would reap 48% of the benefits (they pay 36% of Federal taxes). Yep. That sounds Libertarian alright.
Oddly, 10 months ago when it was those lousy Socialist principles at the helm, we also had the highest U.S. stock market ever, and full employment.
From the original Washington Post article:
So the number may be increasing, as opposed to decreasing, as it has over the last 70 years, but the number is tiny. Over a five year period the number was 2384, or about 475 per year, (there are about 2 million farmers in the U.S.) and only 2% of the number of U.S. farmers leaving the business during the same period.
Adding 0.1% to the U.S. farm population over five years, during which time it actually lost 5% of its famers, is insignificant.
All of the listed reasons for the drying up a pool of young illegal-immigrant farm workers for those Trump-voting farmers to illegally employ for profit are valid.
But the most important reason is not mentioned.
Demographics.
The birth rate in Mexico is now below the replacement rate, as it is in the U.S.
The average (and median) age of illegal border crossers is 20. So a border-crosser today was born in 1997 when the fertility rate in Mexico had already plunged 60%. So the oversupply of young people willing to give up their society and family to live on the margins in the U.S. has disappeared and is not ever coming back.
China is still a permanent member. It was never kicked off at any time.
What did happen was that the UN switched which government was recognized as representing the state of China. Instead of considering the government of the island of Taiwan as representing the entire nation of China, in 1971 the UN switched to recognizing the government of the entire nation of China, except Taiwan. But there has always been a permanent seat for China.
I largely agree with what you say here.
The current DNA system very likely has advantages over alternate systems, on Earth's environment at least. A system with different chirality (direction of coiling) seems quite possible (indeed, it has been difficult to discover any convincing advantage for the chirality we observe on Earth); a DNA with different nucleotide pairing is another possible variation; and "DNA" is actually part of a complex system which can be modified in different ways. For example the coding for additional/alternate amino acids in proteins, or versions of the replication enzymes not found on Earth; or in the epigenetic regulation of gene expression.
And we have an ancestor system, the RNA coding system, that is part of the DNA system. It is widely believed that an "RNA world" of replication preceded the development of the DNA system (since DNA depended on it), so we know that alternate systems are possible.
Given all the pieces that the DNA system on Earth has, it is a little challenging to believe that a system that developed independently in a different planetary (?) environment would be identical in every respect.
OTOH, if life developed on Mars at least, there is good reason to think that Earth's DNA system did not develop independently of that. It looks like meteor bombardment transportation is efficient enough to contaminate Earth with samples Martian biochemistry, including extremophilic organisms. Getting material from Earth to Mars is much harder.
Genuinely alien biochemistry might be difficult to recognize as life, since our most sensitive tools for detection generally depend on known similarities to Earth biochemistry.