Yes that is the whole point which is exactly what having balanced counterweights accomplishes. Once again the system is not the cable it is the cable the earth and the endpoint weight
Do you understand what "damping" means? The "cable the earth and the endpoint" is basically a pendulum, from the frame of reference of the rotating earth. As energy is added, the pendulum starts to swing, and to bounce, and the cable vibrates at each harmonic. The only way that energy is reduced is to somehow covert it into heat.
Even if you didn't use a counterweight the net kinetic energy imparted to the system over a cycle would be zero.
Cycle of what? Lifting a ton to orbit means MWh of energy added to the system as it laterally accelerated the payload, as if you ran your finger down the length of a pendulum, pressing sideways. It will certainly have energy when you're done.
You aren't plucking this cable, you are applying a constant and relatively small force over a period of hours to days.
The fundamental frequency of the cable would be very low indeed, given it's high mass and low proportional stiffness. If it's enough longer than the transit time of the payload, you are indeed plucking it. OK, that's a bit of an oversimplification - you're inducing a wave that will need to damp a bit to become a standing wave, but that's just an even more complex system.
Yes the same way people are being killed all over the place by executive desk toys that are spontaneously undergoing rapid disassembly.
They have a lot more friction (and air resistance, and they make noise, etc). Plus, people don't just keep adding energy to them, or they would start spinning around or slide off the desk.
That's they whole point: you have to damp the energy faster than you add it. A space elevator has little to work with for damping: energy must either be shed as heat, or lost to the atmosphere near the bottom (but that's such a small part of the length). Every ton lifted will mean finding a way to shed MWh of energy, and it's not at all obvious how that mechanical energy could be converted into heat via friction in any reasonable time.
They will quickly find, much to their chagrin, that people will still end up watching Marvel movies rather than some movie about everyone in a French village being struck with a devastating plague of ennui.
What kind of talk is that? We all know a central committee with a five year plan knows better what the consumer needs than th consumer himself. If the plan doesn't work perfectly, it can only be the fault of wreckers, or an unexpectedly cold winter.
The fact that this measure will divert large sums of money from big companies to friends of the decision makers is a total coincidence, of course, and this is totally not a tariff on digital goods. And even if it were a tariff, the current president of the US would never risk a trade war by retaliating, right? Of course not. But if he does, it's totally his fault and not any predictable consequence of our decisions.
Fun fact: the Moon-synchronous orbit height is actually closer to Earth than the moon.
Of course, we could just build it on Mars! Except, well, there's this damn moon that actually orbits lower than Mars-synchronous orbit, and our elevator would have to dodge it every few hours. But that's a minor problem for the engineers, let's not get side-tracked. Mars Elevator!
When your start a normal pendulum swinging, or pluck a guitar string, the energy is eventually dissipated through interaction with the air and friction associated with bending the string (which is quickly lost as heat by conduction). That won't happen with a space elevator. A material suitable for making the cable will shed very little energy through internal friction (otherwise it will get quite hot, as radiative cooling in space sucks).
What that means is any energy put into swinging the pendulum will just stay there. And every payload lifted will add such energy. If it were an ideal pendulum, it would just start swinging with greater amplitude, and maybe you could try to send payloads up in such a way as to damp the swing. A complex pendulum doesn't work that way, however, it will swing and bob and vibrate like a plucked guitar string, and the counterweight will swing about the station. There's no way in such a system to damp that energy by sending payloads up cleverly, or by having some rockets at the station (or at the counterweight).
The complex pendulum will keep accumulating energy until it achieves "rapid unscheduled disassembly" in some unpredictable way.
We have a pretty good idea what will happen if we build it.
Yes: it will swing and bob wildy out of control, and eventually the counterweight will start zooming around the GEO station, if the station is massive. Then the cable will break and the counterweight will shoot off in a random direction, and inevitably destroy Tokyo.
The hard problem for a space elevator, even aside from needing unobtanium, is the lack of any way to damn the pendulum-like energy fed into the system with every payload lifted. Only half the energy needed to get to GEO is in lifting, the other half is in accelerating the payload laterally. That energy will be added to the system with every load lifted, and there's no obvious way to damp it.
And remember, this is not a Freshman Physics pendulum. It's both a spring pendulum and a double pendulum. Each of which is a chaotic system. When combined, it's a mess.
once you get rid of references to fictitious forces
A sure sign of a smug pseudo-intellectual is the claim that "centrifugal force is not a real force". What nonsense. Centrifugal force exists in a rotating reference frame. When your talking about the physics of a rotating reference frame, only a pedantic jerk whines "centrifugal force is not a real force". Don't be that guy.
It's the same performance as their plug-in hybrid GLE (which I was just looking at), which is the fastest GLE engine option unless you go AMG for $120k. But this is the same size as the GLC, where the fastest non-AMG model is the hybrid with 0-60 in 6.2 seconds. It's plenty fast for 99% of SUV drivers.
Hopefully they'll follow up with the full line of SUVs, not just a crossover to compete with the Model X. However, you can tell Mercedes isn't 100% sure of the quality here, as they normally introduce new tech in their highest-end models for a high margin, then eventually work down the range.
Some use cranes on the ships. Some use cranes on the port. Some use conveyor belts, which can be the cheapest and fastest. Ships that "unload themselves" use conveyor belts.
Think about parallelizing movement of bulk freight between ship and port. A bunch of cranes or belts spaced out along the length of the ship, with roughly square hold compartments, is straightforward. A bunch of long, thin compartments running lengthwise not so much. Conveyor loading into long, thin compartments doesn't really work (the pile will hold a certain angle, which may be steep). Also, you can't load a heavy cargo onto a port compartment and a light cargo into a starboard compartment, while you do have some options with the current system.
There's an urban legend that glass is a liquid that just flows slowly, purporting to explain why old glass panes are wavy, and thicker at the bottom than the top. But that's all BS - old glass was wavy when installed, and of course you put the thicker side down so it doesn't fall over while you put the frame around it. Smooth glass of even thickness, "float glass", is a surprisingly recent invention, only commercially viable in the late 1950s.
Solid materials have "friction"; liquids have "viscosity". So, technically there's no friction once it liquefies. It could have been put better, clearly.
Almost all freight is containerized. If bulk cargo were reasonable to containerize, it would have happened long ago, to avoid specialized ships entirely.
he problem with your movement or organization taking a political stance is partisans start fighting back. Just look what's happened to science, AGW has big political implications and the moment it was embraced by "one side" the other side basically became an anti-science political movement.
What he said. The right has been saying to the left for a decade or so now "you keep changing the rules, but you're not going to like the new rules". Politicizing everything seems fun until you start realizing the other side can do it to. And, right now in the US, if you're on the left, you might ponder: hmm, the right has all the political power and seems to be on the rise.
Politicizing everything: think about how it will play out.
Right, because a government conrtolling its borders, something all governments do, it totally the moral equivalent of Hitler. Man, Godwinned on the second post.
Meh, also give unto Caesar his taxes, but they were also low. 10% for government "charity" programs, and 10% to run the actual government - roads and military and whatnot, and you have a perfectly viable system IMO. Everyone has to pay, though.
It always sounds like a strange reasoning to me. I never understood why people want to "survive as a society". I don't even understand what it really means...
All surviving societies are descended from people who wanted to survive as a society, just as all creatures are descended from ancestors that wanted to reproduce. That's what it really means.
If you think your society is good, even though imperfect, you should want it to survive. If you don't think it's good, you should move to someplace good, and mostly leave your old society behind. Simple as that.
he company doesn't pay the 17+63 weeks. They generally pay about 2 weeks. The government pays the rest.
Tech companies in the US offer paid parental leave. It's becoming a broader trend. And my point was, that's not a bad thing.
The spike in autism is very easy to explain.
Yes it is, and the actual medical research points to having kids late in life.
Young Guns
Man, that was a terrible movie. The only thing it had going for it was a lead that teenage girls liked to see.
Consider that an autistic child with ADHD
Two very different conditions. In case you havrn't noticed the change in terminology, "autistic" is the new "mentally retarded". Meanwhile, most ADHD is just young boys failing to act like young girls, a problem intensified by lack of recess periods for the kids to burn their energy off running around.
American was a first world country at one time.
Still is, except in a few cities where there has been only Democratic leadership for 20+ years. Amazing correlation, there.
The IPCC is a political organization. They're therefore selling something. Therefore, they automatically get dismissed as political propaganda - and rightly so - by skeptics.
We learn early to dismiss as lies any claims that a salesman or politician makes.
Seriously, read through http://talkorigins.org/origins... it's short. Note the tone. Read a link to two of the FAQ page - they're interesting. The most convincing stuff there, BTW, is where they say straight up that some examples of evolution commonly taught in high school are just wrong, and that's why they seem wrong - blame the dumbing down, not the actual science.
But, hey, that would be about actually persuading people, not about pride in tribal belonging, and there's little interest in that.
But they're not going to waste their time on something that doesn't hold any scientific water.
String theory. For a couple of decades, if you wanted to do particle physics, you were more-or-less stuck with string theory. If you were of the opinion that it was "not even wrong", well then, don't be a particle physicist.
Humans have politics and fashion.
If the process is pushing a point of view how come no one has gone through those records to show that?
Starting in the 90s, you basically couldn't get funding for any research that questioned global warming - and this was before "the science was settled" (I have this from first-hand accounts of people in related fields). That sort of thing happens a lot - once most scientists reach a "consensus" it can't be questioned if that questioning requires funding, or you'd like to present your paper at a conference, unless of course you're corporate-funded, and then your research is ignored (perhaps rightly so, but still).
Humans have politics and fashion.
And you missed my point: remember when embryonic stem cell research funding was banned in the US? The kratos of the demos affects scintific funding, never doubt it.
It's standard here to have up to 17 weeks pregnancy leave and up to 63 weeks of parental leave (by either parent). It's all unpaid with employment insurance covering 52 weeks of it.
This is paid leave, though. Why should you get paid for not working, ever?
The answer of course is that the US native reproductive rate has fallen below sustaining. If we want to survive as a society, we need to be encouraging each woman to have slightly more than 2 kids. Not to mention that both parents are generally pretty damn useless until the kid starts sleeping through the night, so you might as well deal with that reality.
We sure need to do something to keep professional parents from waiting until nearly 40 before having kids - that's almost certainly the reason for the spike in autism. Personally, I'd like to see a cultural shift in the US to "bust your ass in your 20s, work part time for the rest of your career". I doubt it will happen. but IMO is the correct way to address work-life balance, strategically.
Slashdot Mirror
Yes that is the whole point which is exactly what having balanced counterweights accomplishes. Once again the system is not the cable it is the cable the earth and the endpoint weight
Do you understand what "damping" means? The "cable the earth and the endpoint" is basically a pendulum, from the frame of reference of the rotating earth. As energy is added, the pendulum starts to swing, and to bounce, and the cable vibrates at each harmonic. The only way that energy is reduced is to somehow covert it into heat.
Even if you didn't use a counterweight the net kinetic energy imparted to the system over a cycle would be zero.
Cycle of what? Lifting a ton to orbit means MWh of energy added to the system as it laterally accelerated the payload, as if you ran your finger down the length of a pendulum, pressing sideways. It will certainly have energy when you're done.
The Model X is a crossover, not an SUV.
From observation: successful, wealthy immigrants worried about acceptance in society.
Correct, comrade, capitalism is totally just an inferior form of communism! How could anyone doubt such logic?
You aren't plucking this cable, you are applying a constant and relatively small force over a period of hours to days.
The fundamental frequency of the cable would be very low indeed, given it's high mass and low proportional stiffness. If it's enough longer than the transit time of the payload, you are indeed plucking it. OK, that's a bit of an oversimplification - you're inducing a wave that will need to damp a bit to become a standing wave, but that's just an even more complex system.
Yes the same way people are being killed all over the place by executive desk toys that are spontaneously undergoing rapid disassembly.
They have a lot more friction (and air resistance, and they make noise, etc). Plus, people don't just keep adding energy to them, or they would start spinning around or slide off the desk.
That's they whole point: you have to damp the energy faster than you add it. A space elevator has little to work with for damping: energy must either be shed as heat, or lost to the atmosphere near the bottom (but that's such a small part of the length). Every ton lifted will mean finding a way to shed MWh of energy, and it's not at all obvious how that mechanical energy could be converted into heat via friction in any reasonable time.
They will quickly find, much to their chagrin, that people will still end up watching Marvel movies rather than some movie about everyone in a French village being struck with a devastating plague of ennui.
What kind of talk is that? We all know a central committee with a five year plan knows better what the consumer needs than th consumer himself. If the plan doesn't work perfectly, it can only be the fault of wreckers, or an unexpectedly cold winter.
The fact that this measure will divert large sums of money from big companies to friends of the decision makers is a total coincidence, of course, and this is totally not a tariff on digital goods. And even if it were a tariff, the current president of the US would never risk a trade war by retaliating, right? Of course not. But if he does, it's totally his fault and not any predictable consequence of our decisions.
Fun fact: the Moon-synchronous orbit height is actually closer to Earth than the moon.
Of course, we could just build it on Mars! Except, well, there's this damn moon that actually orbits lower than Mars-synchronous orbit, and our elevator would have to dodge it every few hours. But that's a minor problem for the engineers, let's not get side-tracked. Mars Elevator!
Your reply was a bit of a non-sequitur.
When your start a normal pendulum swinging, or pluck a guitar string, the energy is eventually dissipated through interaction with the air and friction associated with bending the string (which is quickly lost as heat by conduction). That won't happen with a space elevator. A material suitable for making the cable will shed very little energy through internal friction (otherwise it will get quite hot, as radiative cooling in space sucks).
What that means is any energy put into swinging the pendulum will just stay there. And every payload lifted will add such energy. If it were an ideal pendulum, it would just start swinging with greater amplitude, and maybe you could try to send payloads up in such a way as to damp the swing. A complex pendulum doesn't work that way, however, it will swing and bob and vibrate like a plucked guitar string, and the counterweight will swing about the station. There's no way in such a system to damp that energy by sending payloads up cleverly, or by having some rockets at the station (or at the counterweight).
The complex pendulum will keep accumulating energy until it achieves "rapid unscheduled disassembly" in some unpredictable way.
We have a pretty good idea what will happen if we build it.
Yes: it will swing and bob wildy out of control, and eventually the counterweight will start zooming around the GEO station, if the station is massive. Then the cable will break and the counterweight will shoot off in a random direction, and inevitably destroy Tokyo.
The hard problem for a space elevator, even aside from needing unobtanium, is the lack of any way to damn the pendulum-like energy fed into the system with every payload lifted. Only half the energy needed to get to GEO is in lifting, the other half is in accelerating the payload laterally. That energy will be added to the system with every load lifted, and there's no obvious way to damp it.
And remember, this is not a Freshman Physics pendulum. It's both a spring pendulum and a double pendulum. Each of which is a chaotic system. When combined, it's a mess.
The idea of building a tower to Heaven predates history. But a tower is not a workable idea. "Space elevator" means something more specific.
once you get rid of references to fictitious forces
A sure sign of a smug pseudo-intellectual is the claim that "centrifugal force is not a real force". What nonsense. Centrifugal force exists in a rotating reference frame. When your talking about the physics of a rotating reference frame, only a pedantic jerk whines "centrifugal force is not a real force". Don't be that guy.
It's the same performance as their plug-in hybrid GLE (which I was just looking at), which is the fastest GLE engine option unless you go AMG for $120k. But this is the same size as the GLC, where the fastest non-AMG model is the hybrid with 0-60 in 6.2 seconds. It's plenty fast for 99% of SUV drivers.
Hopefully they'll follow up with the full line of SUVs, not just a crossover to compete with the Model X. However, you can tell Mercedes isn't 100% sure of the quality here, as they normally introduce new tech in their highest-end models for a high margin, then eventually work down the range.
Some use cranes on the ships. Some use cranes on the port. Some use conveyor belts, which can be the cheapest and fastest. Ships that "unload themselves" use conveyor belts.
Think about parallelizing movement of bulk freight between ship and port. A bunch of cranes or belts spaced out along the length of the ship, with roughly square hold compartments, is straightforward. A bunch of long, thin compartments running lengthwise not so much. Conveyor loading into long, thin compartments doesn't really work (the pile will hold a certain angle, which may be steep). Also, you can't load a heavy cargo onto a port compartment and a light cargo into a starboard compartment, while you do have some options with the current system.
There's an urban legend that glass is a liquid that just flows slowly, purporting to explain why old glass panes are wavy, and thicker at the bottom than the top. But that's all BS - old glass was wavy when installed, and of course you put the thicker side down so it doesn't fall over while you put the frame around it. Smooth glass of even thickness, "float glass", is a surprisingly recent invention, only commercially viable in the late 1950s.
Solid materials have "friction"; liquids have "viscosity". So, technically there's no friction once it liquefies. It could have been put better, clearly.
Almost all freight is containerized. If bulk cargo were reasonable to containerize, it would have happened long ago, to avoid specialized ships entirely.
he problem with your movement or organization taking a political stance is partisans start fighting back. Just look what's happened to science, AGW has big political implications and the moment it was embraced by "one side" the other side basically became an anti-science political movement.
What he said. The right has been saying to the left for a decade or so now "you keep changing the rules, but you're not going to like the new rules". Politicizing everything seems fun until you start realizing the other side can do it to. And, right now in the US, if you're on the left, you might ponder: hmm, the right has all the political power and seems to be on the rise.
Politicizing everything: think about how it will play out.
Right, because a government conrtolling its borders, something all governments do, it totally the moral equivalent of Hitler. Man, Godwinned on the second post.
Meh, also give unto Caesar his taxes, but they were also low. 10% for government "charity" programs, and 10% to run the actual government - roads and military and whatnot, and you have a perfectly viable system IMO. Everyone has to pay, though.
It always sounds like a strange reasoning to me. I never understood why people want to "survive as a society". I don't even understand what it really means...
All surviving societies are descended from people who wanted to survive as a society, just as all creatures are descended from ancestors that wanted to reproduce. That's what it really means.
If you think your society is good, even though imperfect, you should want it to survive. If you don't think it's good, you should move to someplace good, and mostly leave your old society behind. Simple as that.
he company doesn't pay the 17+63 weeks. They generally pay about 2 weeks. The government pays the rest.
Tech companies in the US offer paid parental leave. It's becoming a broader trend. And my point was, that's not a bad thing.
The spike in autism is very easy to explain.
Yes it is, and the actual medical research points to having kids late in life.
Young Guns
Man, that was a terrible movie. The only thing it had going for it was a lead that teenage girls liked to see.
Consider that an autistic child with ADHD
Two very different conditions. In case you havrn't noticed the change in terminology, "autistic" is the new "mentally retarded". Meanwhile, most ADHD is just young boys failing to act like young girls, a problem intensified by lack of recess periods for the kids to burn their energy off running around.
American was a first world country at one time.
Still is, except in a few cities where there has been only Democratic leadership for 20+ years. Amazing correlation, there.
The IPCC is a political organization. They're therefore selling something. Therefore, they automatically get dismissed as political propaganda - and rightly so - by skeptics.
https://skepticalscience.com/ reads like political propaganda. E.g., this https://skepticalscience.com/a... is a straight up political advocacy blog post. Again, any mixing of politics into your source taints it.
We learn early to dismiss as lies any claims that a salesman or politician makes.
Seriously, read through http://talkorigins.org/origins... it's short. Note the tone. Read a link to two of the FAQ page - they're interesting. The most convincing stuff there, BTW, is where they say straight up that some examples of evolution commonly taught in high school are just wrong, and that's why they seem wrong - blame the dumbing down, not the actual science.
But, hey, that would be about actually persuading people, not about pride in tribal belonging, and there's little interest in that.
But they're not going to waste their time on something that doesn't hold any scientific water.
String theory. For a couple of decades, if you wanted to do particle physics, you were more-or-less stuck with string theory. If you were of the opinion that it was "not even wrong", well then, don't be a particle physicist.
Humans have politics and fashion.
If the process is pushing a point of view how come no one has gone through those records to show that?
Starting in the 90s, you basically couldn't get funding for any research that questioned global warming - and this was before "the science was settled" (I have this from first-hand accounts of people in related fields). That sort of thing happens a lot - once most scientists reach a "consensus" it can't be questioned if that questioning requires funding, or you'd like to present your paper at a conference, unless of course you're corporate-funded, and then your research is ignored (perhaps rightly so, but still).
Humans have politics and fashion.
And you missed my point: remember when embryonic stem cell research funding was banned in the US? The kratos of the demos affects scintific funding, never doubt it.
I would like the time for my fur babies
Twelve weeks is a good amount of time to properly train a puppy. I'll happily take it.
Man, this "fur parents" stuff needs to be killed with fire. Right up there with actual furries, if you ask me!
It's standard here to have up to 17 weeks pregnancy leave and up to 63 weeks of parental leave (by either parent). It's all unpaid with employment insurance covering 52 weeks of it.
This is paid leave, though. Why should you get paid for not working, ever?
The answer of course is that the US native reproductive rate has fallen below sustaining. If we want to survive as a society, we need to be encouraging each woman to have slightly more than 2 kids. Not to mention that both parents are generally pretty damn useless until the kid starts sleeping through the night, so you might as well deal with that reality.
We sure need to do something to keep professional parents from waiting until nearly 40 before having kids - that's almost certainly the reason for the spike in autism. Personally, I'd like to see a cultural shift in the US to "bust your ass in your 20s, work part time for the rest of your career". I doubt it will happen. but IMO is the correct way to address work-life balance, strategically.