We're dealing with small-number statistics here, but no, no astronaut was was ever killed *by* a liquid booster system. Plenty of people were killed on rockets that happened to be using liquid fuels, but the cause of death was life-support failure, cabin fire, or heat shield damage, not the boosters themselves.
Seriously, why does the Federal Reserve have consumer credit card numbers? We're not talking about TJ Maxx here: unless I'm mistaken the Federal Reserve only does business with banks, they have nothing to do with ordinary consumers and their silly bits of plastic.
People putting their income tax payments on plastic, maybe? I'm stumped.
The key phrase in my post is "category error": my point is not that brains and computers can't be compared -- I can compare oranges with communists, or any two things I like. But a category error is falsely deciding that oranges *are* members of the category "communists", brains *are* computers, or Walkmen *are* MP3 players, and using that to draw false conclusions, such as that oranges believe in the virtue of the proletariat.
1. "I think it is because the brain is at heart an analog instead of digital machine. Multiplying integer numbers however isn't a task well suited for analog machines."
The humble slide rule is a beautiful analog computer whose primary job is doing multiplication. A skilled user can do multiplication with one faster than he can use a digital calculator.
2. The brain isn't a digital computer, but it isn't really "analog" either. Individual synapses are either off (not firing) or on (firing), never something in between. But the *rate* at which they fire encodes information in a way that's not analogous to either analog calculating machines or digital computers.
Comparing the human brain to *any* human technology, be it a digital computer or an analog calculator, is a massive category error.
Here's an analogy to illustrate the category error people make when comparing the human brain to a computer:
"A Sony Walkman can record and play music in realtime, fast-forward and rewind, and store an hour's worth of music. These tasks require a 75 Mhz processor and 100 megabytes of memory on an iPod Shuffle. Therefore, a Sony Walkman has a 75 Mhz processor and 100 megabytes of memory."
Under the assumption that those recogntition tasks are inherently memory-intensive, the brain has to have similar amounts of memory at its disposal.
I question the assumption you're making. The nervous system is not a computer in any useful sense: its elemental storage is not in bits, and its elemental operations are not bit logic. To compare its "specs" with a digital computer is to compare apples and oranges.
Example: pitch recognition. How does a computer recognize the pitch of a sound? An incoming audio signal is converted by an analog-to-digital converter and stored as a long string of numbers in memory. A Fourier transformation algorithm is performed to transform this into pitch-vs-amplitude data. The human ear can do the same thing: can we draw conclusions about the ear's memory storage, CPU speed, and analog-to-digital converter specs by the comparison? No, because the human ear doesn't work that way. It does frequency detection "in analog hardware", as a consequence of resonant structures in the cochlea: the signals coming out of the cochlea encode pitch information, yet the cochlea has no memory or CPU at all.
And that's just one tiny simple structure in the human nervous system. Multiply that category error by a million or so to see how false comparing brain processes to computing processes is.
Back to my original point: while at a neurons-and-ganglia level you can't compare the brain to a computer, the *conscious mind* *can* emulate a computer, among other things. But the mind can only emulate a computer with a short-term memory of 7 items, regardless of what you think the "memory" of the underlying substructure is.
And the fact that our conscious short-term memory holds 7 "items", not bits -- the items can be digits, words, names, faces, or objects -- continues to show just how un-like a computer the brain really is.
The brain is not a digital computer in any useful sense. It has no clock, no real concept of "bits", either for data transmission or storage. Its elemental operations are best described in terms of message passing over a network, not in terms of math.
Yes, you can say that it can do tasks that only a powerful computer could perform, but that doesn't mean it's a powerful computer any more than a shark is a very powerful jet-ski. It's not a matter of "not having access" to "low level capability": at a low level, the brain is a totally different thing than a computer.
The parent post has it exactly right. There's nothing new here, wild theories about "routers" and "traffic jams" aside. You can only keep 7 things in your head simultaneously, and multiplying 3-digit numbers takes more memory slots than that.
Exact values vary depending on how you think about the multiplication algorithm, but roughly: 1 digit x 1 digit : max 2 digits to remember at any point, easy task 1 digit x 2 digit : max 3 digits to remember, pretty easy 2 digit x 2 digit : up to 7 digits to remember, difficult but doable for most people 2 digit x 3 digit : up to 9 digits to remember: very difficult 3 digit x 3 digit : up to 14 digits to remember, nearly impossible
Multiplication starts getting difficult right at the point you'd expect based on the age-old "7 items in short-term memory" hypothesis. For confirmation, try doing *subtraction* in your head. It's easy to subtract two 2-digit numbers, because you only need to keep 6 numbers in your head at once. Two 3-digit numbers requires 9 digits of memory: it's difficult but barely doable. Two 4-digit numbers suddenly becomes nearly impossible. Being able to write down *any* of the numbers, either the inputs or the output, for multiplication or subtraction, makes the task drastically easier because it reduces the necessary short-term memory storage.
As you do mental arithmetic and start screwing up, you can *see* what the problem is: it's not a problem of neural bandwidth, it's just that you start forgetting some of the digits you're juggling.
The problem is, you tried to sue a laywer. The funny thing about judges: they used to be lawyers. You remember that old joke claiming that sharks don't eat lawyers out of "professional courtesy"? Same goes for judges. You can sue a doctor, a corporation, or your ex-wife, fine, but if you sue a laywer the entire legal profession closes ranks and roots for the home team.
Ah, but if you want to trade with New York, London, *and* Shanghai, your NY-London chord doesn't look so good. In the limit that you want your trading center to simultaneously minimize the distance to *every* point on the Earth's surface, the center of the Earth is the way to go....still not sure why my OP got modded "insightful", I was shooting for "funny". But I'll take what I can get.
You're thinking too two-dimensionally. Think carefully: what location minimizes the average distance to every spot on the Earth's surface? I'll tell you right now it's not in Siberia! But you should probably spend some extra money on the air conditioning system for your server farm if you want to set up shop there.
The reason adults aren't using the math they learned in school on a daily basis is because the math they learned in school focuses too much on algebra and pre-calc and not enough on statistics. And I say this as a college physics professor, who has a vested interest in encouraging algebra and pre-calc.
Stats is, (well, should be), at the core of every news article you read or watch on TV, at the core of almost every memo you write at work. Good statistical analysis should be at the heart of every political debate you see on TV, and every major economic decision your family makes.
Too often, we're making decisions based on gut instinct, political principle, and anecdotal evidence, and it's causing us to make bad decisions at every level from individual to global. The only cure for this is more stats.
How many decades away would it be when we even remotely possible to have *3* space tourist flights every day?
As the original article points out, there are three companies planning to do this, and their business models plan for 1 flight a day. For *suborbital* rockets using simple propulsion systems, this is not not impossible, if the demand is there. The article says, "what if that actually happened?"
Are they even comparable? Tens (if not hundreds) of thousands flights/ships/buses per day, to, what? One flight per year if they are lucky? No matter where the soot were spilled.
You can't run a business on one flight a year: as I said the article assumes a launch rate matching the business models of the companies who intend to do this. And the computer modeling does indeed show that the effect is significant.
Let me remind you that your argument at the moment is nothing more than "no! that can't be!" I'm not making an appeal to authority here, but if you want to show that this study is bullshit, you need to A) read it, and B) do a calculation which dots as many i's and crosses as many t's as the thing you're trying to refute.
Oh, and also: the authors aren't claiming that these rockets are a bigger deal than traditional tourism: the point is that the environmental impact of space tourism may be very large *relative* to the size of the industry.
A very important distinction: planes, ships, and buses are designed to run clean, with little or no soot output. They also operate in the troposphere, where rainfall "washes" the atmosphere and cleans out the soot and other particles regularly. This is a very different thing than NO+rubber rockets (which are literally as clean-burning as a burning tire) in the stratosphere, where small particles tend to linger for years.
it still remains that no mechanism for the claimed climate changes has been described. It's just, "These guys ran their computer model and this is what they got." That's extremely unhelpful.
If you have access to AGU journals, you should read the original article. It's quite detailed about the mechanisms involved.
Even without the original article, the mechanism here really isn't rocket science. Black stuff in the atmosphere makes the planet absorb more sunlight and therefore heat up. Really simple. To go beyond mechanism to get a numerical estimate of climate change, you unavoidably need a model. And take it from me, the one they're using is a good one.
You're using a lot of breath to cast doubt on the results here, with far less justification for your conclusions than the Nature and Wired authors you're attacking.
Volcanoes generally release sulfate aerosols -- tiny clear droplets of sulfuric acid -- and pale grey ash particles. These are lighter in color than the ground below them, so adding them to the atmosphere makes the planet as a whole lighter in color, so it reflects more sunlight, causing cooling.
Black soot is black: adding it to the atmosphere *darkens* the planet overall, causing it to heat up.
Careful now: FUD as we typically use it on Slashdot is doubt raised by pure rhetoric, in the absence of facts. These guys have actual *data*. You can question their assumptions, but they're not just using scary words.
The obvious question that comes to my mind is why do think that any significant amount of soot from the 1000 rockets launched this year would still be in the atmosphere in 40 years? Do they have any reason to suspect that it stays around that long?
I've found the original Geophysical Research Letter article (it's behind a paywall unless you're at an institution that subscribes to GRL, which I am).
They do *not* assume that the soot sticks around for 40 years: they include a settling time for the soot particles of a couple of years (details more complicated). But they run the model for 40 years to give the ocean and cryosphere time to adjust.
They use a detailed model of the interaction of sunlight with soot particles: this model was developed for studying nuclear holocaust scenarios. They make some assumptions here about the size and properties of rocket soot particles, but I don't see any red flags.
Finally, again comparing to volcano's, the best data I can find for a volcanic eruption that changed the climate (1991 Pinatubo) suggests that it dumped 17 million tons of CO2. I know this is talking about rubber particulates and not CO2, but there's a big difference in magnitude between 17 million tons in a few days and 1.3 million tons over 40 years.
Soot particles have a *very* different climate effect than CO2, it's apples and oranges.
Based on what I read in their article and on my personal experience as a climate modeling scientist, I can tell you that they're using the right computer model for the job, and their assumptions about soot input seem reasonable, and they're including all the relevant physics.
It should also be mentioned that the climate change effects they're predicting (1 polar temperature rise, 5-15% northern polar sea ice loss) are observable, but *much* smaller than the predicted changes from anthropogenic greenhouse gas emissions (up to 8C polar temperature rise, possible total loss of summer sea ice). But still, no joke.
That's essentially what they're doing. The difficulty is that you want to ensure the new mass definition exactly matches the old one. There's no problem in principle with skipping this step, but in practice if you don't you need to throw out every measurement device with a sensitivity greater than the difference in definition.
So to ensure the atomic definition is consistent with the "lump of platinum" one, you need to bridge the gap between the atomic scale and the macroscopic one, which involves counting the number of atoms in a macroscopic object somehow.
Slashdot Mirror
We're dealing with small-number statistics here, but no, no astronaut was was ever killed *by* a liquid booster system. Plenty of people were killed on rockets that happened to be using liquid fuels, but the cause of death was life-support failure, cabin fire, or heat shield damage, not the boosters themselves.
Agree. Solid rocket boosters are only suitable for applications where killing people is a design goal.
Oh, NASA, NASA, when will you learn? You keep trying to make spacecraft, when as we all know your job is to build precision pork delivery vehicles.
Seriously, why does the Federal Reserve have consumer credit card numbers? We're not talking about TJ Maxx here: unless I'm mistaken the Federal Reserve only does business with banks, they have nothing to do with ordinary consumers and their silly bits of plastic.
People putting their income tax payments on plastic, maybe? I'm stumped.
The key phrase in my post is "category error": my point is not that brains and computers can't be compared -- I can compare oranges with communists, or any two things I like. But a category error is falsely deciding that oranges *are* members of the category "communists", brains *are* computers, or Walkmen *are* MP3 players, and using that to draw false conclusions, such as that oranges believe in the virtue of the proletariat.
2 corrections:
1. "I think it is because the brain is at heart an analog instead of digital machine. Multiplying integer numbers however isn't a task well suited for analog machines."
The humble slide rule is a beautiful analog computer whose primary job is doing multiplication. A skilled user can do multiplication with one faster than he can use a digital calculator.
2. The brain isn't a digital computer, but it isn't really "analog" either. Individual synapses are either off (not firing) or on (firing), never something in between. But the *rate* at which they fire encodes information in a way that's not analogous to either analog calculating machines or digital computers.
Comparing the human brain to *any* human technology, be it a digital computer or an analog calculator, is a massive category error.
Here's an analogy to illustrate the category error people make when comparing the human brain to a computer:
"A Sony Walkman can record and play music in realtime, fast-forward and rewind, and store an hour's worth of music. These tasks require a 75 Mhz processor and 100 megabytes of memory on an iPod Shuffle. Therefore, a Sony Walkman has a 75 Mhz processor and 100 megabytes of memory."
Under the assumption that those recogntition tasks are inherently memory-intensive, the brain has to have similar amounts of memory at its disposal.
I question the assumption you're making. The nervous system is not a computer in any useful sense: its elemental storage is not in bits, and its elemental operations are not bit logic. To compare its "specs" with a digital computer is to compare apples and oranges.
Example: pitch recognition. How does a computer recognize the pitch of a sound? An incoming audio signal is converted by an analog-to-digital converter and stored as a long string of numbers in memory. A Fourier transformation algorithm is performed to transform this into pitch-vs-amplitude data. The human ear can do the same thing: can we draw conclusions about the ear's memory storage, CPU speed, and analog-to-digital converter specs by the comparison? No, because the human ear doesn't work that way. It does frequency detection "in analog hardware", as a consequence of resonant structures in the cochlea: the signals coming out of the cochlea encode pitch information, yet the cochlea has no memory or CPU at all.
And that's just one tiny simple structure in the human nervous system. Multiply that category error by a million or so to see how false comparing brain processes to computing processes is.
Back to my original point: while at a neurons-and-ganglia level you can't compare the brain to a computer, the *conscious mind* *can* emulate a computer, among other things. But the mind can only emulate a computer with a short-term memory of 7 items, regardless of what you think the "memory" of the underlying substructure is.
And the fact that our conscious short-term memory holds 7 "items", not bits -- the items can be digits, words, names, faces, or objects -- continues to show just how un-like a computer the brain really is.
The brain is not a digital computer in any useful sense. It has no clock, no real concept of "bits", either for data transmission or storage. Its elemental operations are best described in terms of message passing over a network, not in terms of math.
Yes, you can say that it can do tasks that only a powerful computer could perform, but that doesn't mean it's a powerful computer any more than a shark is a very powerful jet-ski. It's not a matter of "not having access" to "low level capability": at a low level, the brain is a totally different thing than a computer.
The parent post has it exactly right. There's nothing new here, wild theories about "routers" and "traffic jams" aside. You can only keep 7 things in your head simultaneously, and multiplying 3-digit numbers takes more memory slots than that.
Exact values vary depending on how you think about the multiplication algorithm, but roughly:
1 digit x 1 digit : max 2 digits to remember at any point, easy task
1 digit x 2 digit : max 3 digits to remember, pretty easy
2 digit x 2 digit : up to 7 digits to remember, difficult but doable for most people
2 digit x 3 digit : up to 9 digits to remember: very difficult
3 digit x 3 digit : up to 14 digits to remember, nearly impossible
Multiplication starts getting difficult right at the point you'd expect based on the age-old "7 items in short-term memory" hypothesis. For confirmation, try doing *subtraction* in your head. It's easy to subtract two 2-digit numbers, because you only need to keep 6 numbers in your head at once. Two 3-digit numbers requires 9 digits of memory: it's difficult but barely doable. Two 4-digit numbers suddenly becomes nearly impossible. Being able to write down *any* of the numbers, either the inputs or the output, for multiplication or subtraction, makes the task drastically easier because it reduces the necessary short-term memory storage.
As you do mental arithmetic and start screwing up, you can *see* what the problem is: it's not a problem of neural bandwidth, it's just that you start forgetting some of the digits you're juggling.
For God's sake allow me my jaded cynicism! This is Slashdot!
The problem is, you tried to sue a laywer. The funny thing about judges: they used to be lawyers. You remember that old joke claiming that sharks don't eat lawyers out of "professional courtesy"? Same goes for judges. You can sue a doctor, a corporation, or your ex-wife, fine, but if you sue a laywer the entire legal profession closes ranks and roots for the home team.
Sir and/or madam, you just made my day.
Ah, but if you want to trade with New York, London, *and* Shanghai, your NY-London chord doesn't look so good. In the limit that you want your trading center to simultaneously minimize the distance to *every* point on the Earth's surface, the center of the Earth is the way to go. ...still not sure why my OP got modded "insightful", I was shooting for "funny". But I'll take what I can get.
You're thinking too two-dimensionally. Think carefully: what location minimizes the average distance to every spot on the Earth's surface? I'll tell you right now it's not in Siberia! But you should probably spend some extra money on the air conditioning system for your server farm if you want to set up shop there.
Rule #1 of buying stuff: the vendor is not your "friend", on Facebook or otherwise.
The reason adults aren't using the math they learned in school on a daily basis is because the math they learned in school focuses too much on algebra and pre-calc and not enough on statistics. And I say this as a college physics professor, who has a vested interest in encouraging algebra and pre-calc.
Stats is, (well, should be), at the core of every news article you read or watch on TV, at the core of almost every memo you write at work. Good statistical analysis should be at the heart of every political debate you see on TV, and every major economic decision your family makes.
Too often, we're making decisions based on gut instinct, political principle, and anecdotal evidence, and it's causing us to make bad decisions at every level from individual to global. The only cure for this is more stats.
How many decades away would it be when we even remotely possible to have *3* space tourist flights every day?
As the original article points out, there are three companies planning to do this, and their business models plan for 1 flight a day. For *suborbital* rockets using simple propulsion systems, this is not not impossible, if the demand is there. The article says, "what if that actually happened?"
Are they even comparable? Tens (if not hundreds) of thousands flights/ships/buses per day, to, what? One flight per year if they are lucky? No matter where the soot were spilled.
You can't run a business on one flight a year: as I said the article assumes a launch rate matching the business models of the companies who intend to do this. And the computer modeling does indeed show that the effect is significant.
Let me remind you that your argument at the moment is nothing more than "no! that can't be!" I'm not making an appeal to authority here, but if you want to show that this study is bullshit, you need to A) read it, and B) do a calculation which dots as many i's and crosses as many t's as the thing you're trying to refute.
Oh, and also: the authors aren't claiming that these rockets are a bigger deal than traditional tourism: the point is that the environmental impact of space tourism may be very large *relative* to the size of the industry.
A very important distinction: planes, ships, and buses are designed to run clean, with little or no soot output. They also operate in the troposphere, where rainfall "washes" the atmosphere and cleans out the soot and other particles regularly. This is a very different thing than NO+rubber rockets (which are literally as clean-burning as a burning tire) in the stratosphere, where small particles tend to linger for years.
it still remains that no mechanism for the claimed climate changes has been described. It's just, "These guys ran their computer model and this is what they got." That's extremely unhelpful.
If you have access to AGU journals, you should read the original article. It's quite detailed about the mechanisms involved.
Even without the original article, the mechanism here really isn't rocket science. Black stuff in the atmosphere makes the planet absorb more sunlight and therefore heat up. Really simple. To go beyond mechanism to get a numerical estimate of climate change, you unavoidably need a model. And take it from me, the one they're using is a good one.
You're using a lot of breath to cast doubt on the results here, with far less justification for your conclusions than the Nature and Wired authors you're attacking.
To oversimplify:
Volcanoes generally release sulfate aerosols -- tiny clear droplets of sulfuric acid -- and pale grey ash particles. These are lighter in color than the ground below them, so adding them to the atmosphere makes the planet as a whole lighter in color, so it reflects more sunlight, causing cooling.
Black soot is black: adding it to the atmosphere *darkens* the planet overall, causing it to heat up.
Careful now: FUD as we typically use it on Slashdot is doubt raised by pure rhetoric, in the absence of facts. These guys have actual *data*. You can question their assumptions, but they're not just using scary words.
The obvious question that comes to my mind is why do think that any significant amount of soot from the 1000 rockets launched this year would still be in the atmosphere in 40 years? Do they have any reason to suspect that it stays around that long?
I've found the original Geophysical Research Letter article (it's behind a paywall unless you're at an institution that subscribes to GRL, which I am).
They do *not* assume that the soot sticks around for 40 years: they include a settling time for the soot particles of a couple of years (details more complicated). But they run the model for 40 years to give the ocean and cryosphere time to adjust.
They use a detailed model of the interaction of sunlight with soot particles: this model was developed for studying nuclear holocaust scenarios. They make some assumptions here about the size and properties of rocket soot particles, but I don't see any red flags.
Finally, again comparing to volcano's, the best data I can find for a volcanic eruption that changed the climate (1991 Pinatubo) suggests that it dumped 17 million tons of CO2. I know this is talking about rubber particulates and not CO2, but there's a big difference in magnitude between 17 million tons in a few days and 1.3 million tons over 40 years.
Soot particles have a *very* different climate effect than CO2, it's apples and oranges.
Based on what I read in their article and on my personal experience as a climate modeling scientist, I can tell you that they're using the right computer model for the job, and their assumptions about soot input seem reasonable, and they're including all the relevant physics.
It should also be mentioned that the climate change effects they're predicting (1 polar temperature rise, 5-15% northern polar sea ice loss) are observable, but *much* smaller than the predicted changes from anthropogenic greenhouse gas emissions (up to 8C polar temperature rise, possible total loss of summer sea ice). But still, no joke.
That's essentially what they're doing. The difficulty is that you want to ensure the new mass definition exactly matches the old one. There's no problem in principle with skipping this step, but in practice if you don't you need to throw out every measurement device with a sensitivity greater than the difference in definition.
So to ensure the atomic definition is consistent with the "lump of platinum" one, you need to bridge the gap between the atomic scale and the macroscopic one, which involves counting the number of atoms in a macroscopic object somehow.
A microwave oven's power source is not a maser, just like an incandescent light bulb is not a laser.
If you don't understand the distinction, PLEASE don't open up your microwave and try to make a death ray.