In the last discussion we had. You're getting very close to troll territory my friend.
Trolling implies an attempt to annoy or start a flame war for one's own amusement. I would appreciate it if you not throw the term around like that - nothing I've said or done even comes close.
As for the proposed skyramp idea, I'm all for it. From what the link says, what you'r essentially doing is building a diagonal runway to "...propel an RLV on a sled to supersonic speeds up a long inclined track before the RLV fires its engines.". It seems a bit like the system aircraft carriers use, albeit scaled up: http://en.wikipedia.org/wiki/Aircraft_catapult
It's not a space elevator equivalent however. What you're doing here is more akin to replacing the boosters on a shuttle-type craft with a different system to help it attain orbit.
With a space elevator, assuming the endpoint was far enough away, you could send something up with enough force to escape the Earth's gravity well. What's more, the longer the cable, the more forcibly the craft can be launched. That alone makes it an attractive concept, and it's something that neither of the ideas you've linked seems to replicate (feel free to correct me if I've misread them).
I'm not sure we can build a space elevator - we'd need a great deal of R&D into materials engineering to even consider it. But unlike the person I replied to, I'm all in favour of trying, and I do not think we'll have a better system developed that can do the same job.
There are several commercial launchers... Despite the subsidised national space agencies.
What do you think made those possible? All the first order research was done by NASA, or it's counterparts, decades ago. Without that hard work and "wasted" money we would neve have developed the requisite launch technology.
What do you think a space elevator will use, fairy dust? It will consume vast quantities of energy both to build and to operate.
In terms of energy losses, the elevators are generally accepted to be more effecient (admittedly this is theoretical).
It takes enourmous amounts of energy to put anything in orbit. Period. Future technology, in whatever form it takes, will face the same physical limits.
Rocket fuels aren't cheap, and aren't going to get cheaper. Moreover, rockets have a very low weight limit - those commercial launches you mention put up tiny satellites, and even then they cost through the nose.
Show me the advanced launch tech that can put something heavy in orbit today. Oh, right, it's that model of effeciency the space shuttle. Trust me, if that's the cost per pound that a space elevator has to beat, we could make it out of pure gold and still come out ahead.
We don't have anything that can do what a space elevator can. Unless you can show me an example of a launch system (existing or theoretical) that can carry the same weight, then your arguement that "by the time we can build the space elevator, we'll have better tech", is invalid. Seriously, go take a look at stuff like the X-prize craft - these are the "spaceships of tommorow" and they still carry very little payload, to no higher than LEO, for a hefty price.
Same applies for launch vehicles. If they were cheaper, we wouldn't need NASA to develop them, now, would we? Yet virtually all first order space research is done by them, or other national space agencies.
Cheaper =! cheap. All cheaper means is that it's the option that has a relatively lower cost per pound/kilo to put in orbit. At current launch prices, a space elevator could be hellishly expensive to build, and still be cheaper by the pound once it's in service.
Remember that any one shot or resuable lauch vehicle using chemical propulsion has the unavoidable cost of fuel, which means that launching large payloads into space is always going to cost throught the nose for the forseeable future. Unless we develop anti gravity or some other blue sky idea into a workable launch mechanism, however I wouldn't bank on it.
By the time we have the technology for space elevators, far superior modes of lift and orbital flight will exist.
Name them.
Seriously, show me the tech that you propose will make space elevators unneccesary. Show me the orbital equivalent of a transatlantic ship, and more importantly show me that it's cheaper.
Otherwise, I don't see why your point is a valid arguement.
Furthermore, the atlantic bridge arguement is a red herring. This is the equivalent of building a bridge where previously ferries were used. Furthermore, even if we did have cheaper ground to orbit craft, a longer space elevator can be used to give the ascending craft enough escape velocity to clear Earth's gravity well, which is something that ground to orbit craft can't do.
We'd also need a way to strip the atmosphere. We're talking a surface density about 90 times that of the Earth, most of which would need to be tossed. Or else we'd need to fix it into something other than gasses. Plus, how would we deal with the days that last the equivalent of 230+ Earth days?
Though, if we're going to go with a blue sky idea here, I suppose we could find something large enough and simply ram the planet at the right angle. Blow away most of the air in the collision and transfer the projectile planet's momentum into Venusian rotational velocity. The question then becomes what we'd hit it with, and how we'd move such an object...
Re:It's a common mistake but is there proof?
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Humanity Gene Found?
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Have you tested that theory experimentally?
I assure you sir, there is no way to test this theory that is not "experimental":-)
In your defense, they're quite hard to tell apart once you've had a few Duffs. What look like slightly unshaven legs and sloping posture the night before reveal themselves fully in the morning after.
Room temperature is about 300 degrees higher than absolute zero (C or kelvins). Venus is over 400 degrees hotter than Earth norms. And we require heavy machinery to cool a small area to abosolute zero - the cooling systems are larger than the area they cool. This doesn't even get into energy requirements, or safety systems/redundancy, or the numerous issues associated with the Venusian environment.
In total, we'd need a complex and enourmous cooling system, a habitat capable of surviving Venusian pressure, and the means to get both items there. We have deep sea craft, but they're tiny, we have the ability to cool small amounts of matter to absolute zero, but it requires enourmous machinery, and we have launch vehicles, but they can't carry much weight.
So yeah, saying we could put a colony or habitat on Venus is handwaiving. It's damn near impossible, and even where it is just barely possible, there is no way we could do it in the present or the near future. All of this just to put a few humans in a bubble on the least appealing planet in our solar system (well, maybe not - Mercury is at least as bad).
Conversely, we could get to Mars (arguably the second best planet from a human-habitability standpoint) using little more technology than we have already.
are you implying that current DVD and SD displays are the "peak" of home theater technology?
For the average user? Yes.
You may very well be correct in your assessment that they aren't using HD to it's full potential yet. If so, there may very well be a market when and if they do. I won't make a prediction either way, as I do not feel qualified.
But for the average user? They jumped wholesale to DVDs, and it wasn't just the picture quality that did it for them. VCRs are an inferior technology on so many levels - from the need to rewind or fast forward if there is a specific part of the movie you want to see, to the noticable degredation of the tape after only a few years of regular use. DVDs were better in every sense of the word, and early adopters flocked to them, with the average users following shortly thereafter. That isn't happening this time.
Now, will it happen if true HD becomes available? I can't say. But even if that does happen, it will not be on par with the shift from VHS to DVD, if only because it's an improvement in the area of picture quality alone, and not overall usability.
Actually, what I was getting at was more that the sound chip was like a VHS tape, and the sound card like a DVD. The general idea being that once you have a mature version of a technology, there is little to be gained from upgrading yet again.
So, I fully agree that these new formats aren't sufficiently better than DVDs to justify their cost and drawbacks. That was my point:-)
We've seen the same sort of thing happen to computer technology as well.
If you're a gamer when was the last time you upgraded your graphics card? It's probably the newest part of your system, right?
Now, when was the last time you upgraded your sound card? Probably never. Yet I do recall a time when decent sound was a big deal - I can still remember firs playing Doom with the chirping onboard speakers as a kid, and later being blown away when we got a new computer that had an actual sound card installed.
Technology peaks. It happens. And when it does, all the early adopters in the world aren't going to make a difference. We aren't easy marks; we have to think there's something for us in the bargin if we shell out for a better system or part.
And what you're doing is called "ignoring history". In 66 years we went from powered flight to landing on the moon. If we really need to do something, we can usually do it in short order.
Yet within the realm of science, we didn't have to advance much to get from one to the other. We needed an understanding of rocketry, some knowledge of life support, some advances in various engineering disciplines. That isn't to say what we accomplished wasn't difficult, but scientifically the groundwork for everything from the Wright brothers to the Apollo program is basically Newton's laws of motion.
Yup, see above. By the time we are colonising Venus, we'll already have deep orbit refineries building whatever we want, but sadly mostly automated and robotic. I mean there is one asteroid up there, just one of who knows how many, with 5 tons of good quality iron for every man, woman and child on earth, Amun something. I'm not suggesting we start shipping up ocean exploration vehicles piecemeal until we have a Venusian city.
Just out of curiosity, how exacly do you propose building these refineries?
I ask because any sort of industrial technology requires a lot of startup hardware. Moreso in space since you've got to take into account the limitations imposed by automation, or else deal with the problems associated with long term space habitation and life support, and you've got to get from Earth orbit to wherever it is in the asteroid belt you're planning to mine/build. All of this is going to add to the mass of whatever we initially launch into orbit.
Have you checked the price of putting something in even LEO lately? We need to make serious improvements to our launch technology first if we're going to do anything like building stuff in the belt. So, that means going from better launch tech, to asteroid expansion, to developing and building Venusian habitats, all before we even think about putting people on Venus. Sounds a lot harder than calcium pills for Mars to me.
Coolant is not cold. Get that fact memorized. Coolant is what you use to make something else cold. Hence the more technical term "heat transfer fluid".
On Venus, coolant would have to be superheated to a temperature greater than the Venusian air by compression, then cooled to terrestrial temperatures by expansion in order to cool a habitat. This isn't even remotely possible with modern heat pump technology. It may never be possible. The laws of thermodynamics aren't breakable, so even if we could provide a fluid that had the properties we need, the energy requirements involved in initiating that kind of temperature change will be enourmous.
Hell if all else fails set up a series of highly insulated chambers to funnel your hot material through.
Also doesn't work. You want your heat sink to be conductive, not insulated. Remember that a heat sink heats up over time, so you'll want to let it dissipate if you plan on using it continously. An ideal heat sink is a deep pool of cold water exposed to open air, which is easy to find on Earth, but a wee bit difficult to swing on Venus.
This is not an insurmountable engineering challenge, although it is a large one.
Actually, it is insurmoutable using modern technology, and I don't share your optimism about what we'll have available in the future. Some limits have nothing to do with technology and everything to do with the laws of physics (in this case, thermodynamics)
I rather suspect the temperature 500 meters below the surface is fairly nippy.
Insufficient data, unfortunately. We have no clue what the temperature is. All our Venusian probes have been extrememly short lived, or else have confined themselves to orbital examination (which will not tell you much about the interior of a planet, except by inference).
The whole point about AC systems is essentially that they take heat from the inside environment, condense it (using energy in the process), then allow it to radiate into the outside. You can cool a cold environment by venting into a hotter one, but there are limits imposed by things like the phase changes of matter, and energy requirements. On Venus, your "coolant" would have to reach a temperature exceeding 400 degrees C in order to transfer heat into the air, and then subsequently drop to a temperature of about 25 degrees C to cool the habitat.
Cooling anything to terrestrial temperatures in Venusian heat and pressure is going to be damn near impossible, if not completely impossible. No amount of handwaiving will change that.
What you're posting is called "handwaiving". You're ignoring major technical or physical hurdles by saying "we can do it in the future".
Pressure is no problem, as you mentioned we have already overcome that issue, and as time goes on, the solutions will become more elegant and require less adjustment on our part.
I did not say we'd overcome this already. We've build small, expensive and heavy vehicles for deep sea exploration. These will not work on Venus as they are now.
Even if we could scale them up to colony sizes, how would we transport them there? Try imagining moving something the size of a SSBN-type submarine across interplanetary space. Now consider that our hypothetical colony would actually be heavier, since SSBNs aren't rated for that kind of pressure, nevermind temperature. Now, factor in the problems associated with assembling it in place, assuming we moved it in pieces (trying to construct anything on Venus is going to be difficult, if not impossible, using even futuristic technology).
Temperature likewise, if we can create air conditioning on a mass scale
even in locations where there is no "cool" to draw from, we can surely manufacture similar systems for more extreme locations, even if it means manufacturing or extracting the coolants on the Venusian surface
You don't manufactor or extract coolant in order to cool something. At all.
Coolant is just used to transport heat from a hot environment to a cold one, then sent back to the hot environment to pick up more heat. Think of it as a conveyer belt.
More coolant, or fresh coolant, doesn't do the least bit of good. What matters is transfering heat to a heat sink, which can be done by recycling coolant. But in order to do any of this, you must first have a cooler environment to act as a heat sink. ACs and refigerators (and every other piece of technology we have for cooling things) use the outside air as a heat sink which doesn't work on Venus, since the outside air is 400 degrees.
Dump the "hot" the same place it is always dumped; outside.
Got it? There is no way to cool something unless you're venting heat into a colder environment. A closed system with energy in it will gradually convert all that energy to waste heat, while an open system on Venus will quickly rise to the same temperature as the air.
The only things I can even imagine serving as a heat sink on Venus are a shallow geothermic loop or a massive radiator fin in space. Geothermic loops may or may not work depending on whether it's colder underground than on the surface. Space radiators would work, if it weren't for the fact that we have no way to connect them to the surface (and don't even think of suggesting a space elevator - Venus has a rotational period that's slightly longer than a Venusian year, which precludes any sort of elevator).
Plus, for all the trouble you're suggesting we go through to avoid dealing with martian gravity, wouldn't it be simpler just to develop medical treatments for bone loss? That seems far less impossible to me than trying to live on Venus.
If there are rocks on Venus, build em out of venus-rocks like eskimos!:D
Doesn't work.
Lets say you want to build a shelter underground on Venus. You'll want it to be close to the temperature and pressure on earth, right? We're assuming that people are going to live here.
Well, temperature is the first problem. The rocks may not melt, but that doesn't mean they somehow stop conducting heat. Every single form of cooling technology we have just moves heat around instead of getting rid of it, and moreover this is a physical limitation, rather than an engineering one (damn pesky thermodynamic laws). You need a cool place to dump excess heat into. Where the hell are you going to put a heat sink on Venus?
Pressure is the second problem. Even if you were to build a shelter underground, the space contained within would still be the same pressure as the outside air (about 90 times that of Earth IIRC). If we depressurized it to Earth standard, then we'd be up against the problems associated with the oudside pressure bearing down on the shelter, which would crush it.
On Earth the only environment with a similar pressure is about 1 kilometer below the surface of the ocean. Have you seen what kind of engineering specifications are required for a craft that goes that deep and only carries a few people? Try and imagine building a base to survive that same pressure, plus the heat and corrosiveness of the Venusian atmosphere. Now remember that we're talking about a base that's going to be there for years, whereas the deep ocean submersibles go down for hours, and that the base is going to house some large number of personel, while submersibles carry typically no more than two or three.
(Which is one of the reasons why strong constitutional protection for speech is a Good Thing (TM))
If you look at what's happening in the US right now (election year, *sigh*) even with constitutional protection this sort of political monkey business still happens. Just take a look at all the violent video game laws that have been reported on/. lately.
The primary problem is that there is no penalty for legislatures that pass unconstitutional laws, other than a waste of tax dollars (which doesn't affect them directly anyway). Instead you get laws that blatantly violate the first amendment passed, then struck down the moment they're challenged in court. This doesn't bother the politicians sponsoring the bills, because they can then claim to their consitutents that they tried to pass a "virtuous" law, but were blocked by "activist" judges.
Constitutional protections are vitally neccesary to prevent bad laws from being enforced, but they don't actually deter this kind of manipulative behaviour. And the cost is both to the judicial system, which gets demonized by political hacks for doing its job, and the taxpayer, who ends up footing the bill.
True that. Though I'd say that if there is something vastly more important overshadowing the effect you're looking for, then the effect that's being overshadowed is probably very small by comparison.
If C is making it impossible to correctly correlate A and B, then either C is much more statistically signifigant than A/B, or else the relationship between A and B is insignifigant enough that small entangled effects can make the connection between them unmeasurable. If it's the former, then I'd say we're making fine progress in stopping rape without kneejerk laws, whereas if it's the latter then porn is such a small contributer that trying to remove it isn't going to noticable affect the sex crime rate.
Of course, that assumes that there is a third factor overshadowing the correlation. My take would be that reduced sexual repression leads to both a reduction in rape and an increase in porn - in other words, that the correlative relationship is pointing to a larger overall change in society's attitudes.
Of course, no matter how you slice it, the law in TFA doesn't gell terribly well with the study linked by the GP.
Couldn't the orbit decay and finally crash on the far side of the moon?
Not totally sure about the rest of your post, but I the answer here is "no".
Orbital decay only occurs when a satelite is within the atmosphere of the body it orbits. It's caused by air resistance sapping the satelite's orbital velocity.
Since the moon is essentially airless, this won't happen. You could (at least in theory) orbit as close to the moon as you like as long as your path doesn't smack into the side of a mountain. In practice, I'm not sure I'd want to risk it, but it's certainly not against the laws governing orbital mechanics.
Over extremely long time periods, you'd run into problems, since "essentially airless" is not quite the same as "totally airless" (even in deep space there is no true vacuum), but I suspect we'd be talking about decades at a minimum here.
True, but then again we don't have to prove a causitive arguement to debunk the basis for this law.
The woman advocating the law is stating that there is a relationship between porn and sex crimes. She is stating that the man who strangled her daughter was in some way either motivated or empowered by porn.
Now, correlation does not always equal causation, but as far as I know causation will always include correlation. Ie, you cannot have A causing B without also having A correlating to B. So, if her arguement were valid, then you'd expect a causitive relationship between porn and violence to coincide with a correlation between the two, right?
Now, what these studies show is a lack of correlation. In fact, they show an inverse correlation, which is exactly the opposite of what you'd expect. So either the mother has to be incorrect in her assessment of a sex offender, or else the researchers must be wrong.
Call me cold hearted, but I will take the word of a researcher over the word of an emotionally charged mother who has lost a daughter. Being traumatized by a criminal act does not grant you any degree of insight into a criminal mind.
The brain turned adaptability from hardware to software. With a brain that can reason, the long process of evoultionary selection is not so necessary for short term environmental changes. Some of the environmental changes can be compensated for be behavioral (software) changes. This gives our species orders of magnitude greater adaptability.
Best computer analogy I've seen on the subject.:-)
People complain about government stepping in, but the population at large does nothing to reign in their own vices or show SOME measure of standards as to what society will put up with.
Right, because pedos, rapists and psychopaths are typical citizens in all other regards. In fact, if it weren't for the prevalence of vice, they would never harm a fly./sarcasm
The actions of a few sick and twisted individuals is not typical of the standards of society. Was dear old Jack the Ripper a typical 19th century gentleman?
The problem with your line of reasoning is the incontrivertable fact that violent crime rates have been steadily progressing downwards for decades, especially in areas like youth crime. It's not that there weren't sick and dangereous criminals in decades or centuries past, it's that they weren't as high profile. The fact that we have tabloids, CNN and legions of hungry journalists out looking for the next Manson/Jack/Son of Sam only means that we hear about such individuals more often.
It isn't lack of standards in our society that's the problem, it's an overabundance of boogeymen.
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As for the proposed skyramp idea, I'm all for it. From what the link says, what you'r essentially doing is building a diagonal runway to "...propel an RLV on a sled to supersonic speeds up a long inclined track before the RLV fires its engines.". It seems a bit like the system aircraft carriers use, albeit scaled up:
http://en.wikipedia.org/wiki/Aircraft_catapult
It's not a space elevator equivalent however. What you're doing here is more akin to replacing the boosters on a shuttle-type craft with a different system to help it attain orbit.
With a space elevator, assuming the endpoint was far enough away, you could send something up with enough force to escape the Earth's gravity well. What's more, the longer the cable, the more forcibly the craft can be launched. That alone makes it an attractive concept, and it's something that neither of the ideas you've linked seems to replicate (feel free to correct me if I've misread them).
I'm not sure we can build a space elevator - we'd need a great deal of R&D into materials engineering to even consider it. But unlike the person I replied to, I'm all in favour of trying, and I do not think we'll have a better system developed that can do the same job.
In terms of energy losses, the elevators are generally accepted to be more effecient (admittedly this is theoretical).
It takes enourmous amounts of energy to put anything in orbit. Period. Future technology, in whatever form it takes, will face the same physical limits.
Rocket fuels aren't cheap, and aren't going to get cheaper. Moreover, rockets have a very low weight limit - those commercial launches you mention put up tiny satellites, and even then they cost through the nose.
Show me the advanced launch tech that can put something heavy in orbit today. Oh, right, it's that model of effeciency the space shuttle. Trust me, if that's the cost per pound that a space elevator has to beat, we could make it out of pure gold and still come out ahead.
We don't have anything that can do what a space elevator can. Unless you can show me an example of a launch system (existing or theoretical) that can carry the same weight, then your arguement that "by the time we can build the space elevator, we'll have better tech", is invalid. Seriously, go take a look at stuff like the X-prize craft - these are the "spaceships of tommorow" and they still carry very little payload, to no higher than LEO, for a hefty price.
Same applies for launch vehicles. If they were cheaper, we wouldn't need NASA to develop them, now, would we? Yet virtually all first order space research is done by them, or other national space agencies.
Cheaper =! cheap. All cheaper means is that it's the option that has a relatively lower cost per pound/kilo to put in orbit. At current launch prices, a space elevator could be hellishly expensive to build, and still be cheaper by the pound once it's in service.
Remember that any one shot or resuable lauch vehicle using chemical propulsion has the unavoidable cost of fuel, which means that launching large payloads into space is always going to cost throught the nose for the forseeable future. Unless we develop anti gravity or some other blue sky idea into a workable launch mechanism, however I wouldn't bank on it.
Seriously, show me the tech that you propose will make space elevators unneccesary. Show me the orbital equivalent of a transatlantic ship, and more importantly show me that it's cheaper.
Otherwise, I don't see why your point is a valid arguement.
Furthermore, the atlantic bridge arguement is a red herring. This is the equivalent of building a bridge where previously ferries were used. Furthermore, even if we did have cheaper ground to orbit craft, a longer space elevator can be used to give the ascending craft enough escape velocity to clear Earth's gravity well, which is something that ground to orbit craft can't do.
We'd also need a way to strip the atmosphere. We're talking a surface density about 90 times that of the Earth, most of which would need to be tossed. Or else we'd need to fix it into something other than gasses. Plus, how would we deal with the days that last the equivalent of 230+ Earth days?
Though, if we're going to go with a blue sky idea here, I suppose we could find something large enough and simply ram the planet at the right angle. Blow away most of the air in the collision and transfer the projectile planet's momentum into Venusian rotational velocity. The question then becomes what we'd hit it with, and how we'd move such an object...
In your defense, they're quite hard to tell apart once you've had a few Duffs. What look like slightly unshaven legs and sloping posture the night before reveal themselves fully in the morning after.
Room temperature is about 300 degrees higher than absolute zero (C or kelvins). Venus is over 400 degrees hotter than Earth norms. And we require heavy machinery to cool a small area to abosolute zero - the cooling systems are larger than the area they cool. This doesn't even get into energy requirements, or safety systems/redundancy, or the numerous issues associated with the Venusian environment.
In total, we'd need a complex and enourmous cooling system, a habitat capable of surviving Venusian pressure, and the means to get both items there. We have deep sea craft, but they're tiny, we have the ability to cool small amounts of matter to absolute zero, but it requires enourmous machinery, and we have launch vehicles, but they can't carry much weight.
So yeah, saying we could put a colony or habitat on Venus is handwaiving. It's damn near impossible, and even where it is just barely possible, there is no way we could do it in the present or the near future. All of this just to put a few humans in a bubble on the least appealing planet in our solar system (well, maybe not - Mercury is at least as bad).
Conversely, we could get to Mars (arguably the second best planet from a human-habitability standpoint) using little more technology than we have already.
You may very well be correct in your assessment that they aren't using HD to it's full potential yet. If so, there may very well be a market when and if they do. I won't make a prediction either way, as I do not feel qualified.
But for the average user? They jumped wholesale to DVDs, and it wasn't just the picture quality that did it for them. VCRs are an inferior technology on so many levels - from the need to rewind or fast forward if there is a specific part of the movie you want to see, to the noticable degredation of the tape after only a few years of regular use. DVDs were better in every sense of the word, and early adopters flocked to them, with the average users following shortly thereafter. That isn't happening this time.
Now, will it happen if true HD becomes available? I can't say. But even if that does happen, it will not be on par with the shift from VHS to DVD, if only because it's an improvement in the area of picture quality alone, and not overall usability.
Actually, what I was getting at was more that the sound chip was like a VHS tape, and the sound card like a DVD. The general idea being that once you have a mature version of a technology, there is little to be gained from upgrading yet again.
:-)
So, I fully agree that these new formats aren't sufficiently better than DVDs to justify their cost and drawbacks. That was my point
We've seen the same sort of thing happen to computer technology as well.
If you're a gamer when was the last time you upgraded your graphics card? It's probably the newest part of your system, right?
Now, when was the last time you upgraded your sound card? Probably never. Yet I do recall a time when decent sound was a big deal - I can still remember firs playing Doom with the chirping onboard speakers as a kid, and later being blown away when we got a new computer that had an actual sound card installed.
Technology peaks. It happens. And when it does, all the early adopters in the world aren't going to make a difference. We aren't easy marks; we have to think there's something for us in the bargin if we shell out for a better system or part.
Just out of curiosity, how exacly do you propose building these refineries?
I ask because any sort of industrial technology requires a lot of startup hardware. Moreso in space since you've got to take into account the limitations imposed by automation, or else deal with the problems associated with long term space habitation and life support, and you've got to get from Earth orbit to wherever it is in the asteroid belt you're planning to mine/build. All of this is going to add to the mass of whatever we initially launch into orbit.
Have you checked the price of putting something in even LEO lately? We need to make serious improvements to our launch technology first if we're going to do anything like building stuff in the belt. So, that means going from better launch tech, to asteroid expansion, to developing and building Venusian habitats, all before we even think about putting people on Venus. Sounds a lot harder than calcium pills for Mars to me.
http://en.wikipedia.org/wiki/Coolant Take a look there.
Coolant is not cold. Get that fact memorized. Coolant is what you use to make something else cold. Hence the more technical term "heat transfer fluid".
On Venus, coolant would have to be superheated to a temperature greater than the Venusian air by compression, then cooled to terrestrial temperatures by expansion in order to cool a habitat. This isn't even remotely possible with modern heat pump technology. It may never be possible. The laws of thermodynamics aren't breakable, so even if we could provide a fluid that had the properties we need, the energy requirements involved in initiating that kind of temperature change will be enourmous.
Also doesn't work. You want your heat sink to be conductive, not insulated. Remember that a heat sink heats up over time, so you'll want to let it dissipate if you plan on using it continously. An ideal heat sink is a deep pool of cold water exposed to open air, which is easy to find on Earth, but a wee bit difficult to swing on Venus.
Actually, it is insurmoutable using modern technology, and I don't share your optimism about what we'll have available in the future. Some limits have nothing to do with technology and everything to do with the laws of physics (in this case, thermodynamics)
Insufficient data, unfortunately. We have no clue what the temperature is. All our Venusian probes have been extrememly short lived, or else have confined themselves to orbital examination (which will not tell you much about the interior of a planet, except by inference).
Oh, and as a addendum to what I wrote.
The whole point about AC systems is essentially that they take heat from the inside environment, condense it (using energy in the process), then allow it to radiate into the outside. You can cool a cold environment by venting into a hotter one, but there are limits imposed by things like the phase changes of matter, and energy requirements. On Venus, your "coolant" would have to reach a temperature exceeding 400 degrees C in order to transfer heat into the air, and then subsequently drop to a temperature of about 25 degrees C to cool the habitat.
Cooling anything to terrestrial temperatures in Venusian heat and pressure is going to be damn near impossible, if not completely impossible. No amount of handwaiving will change that.
I did not say we'd overcome this already. We've build small, expensive and heavy vehicles for deep sea exploration. These will not work on Venus as they are now.
Even if we could scale them up to colony sizes, how would we transport them there? Try imagining moving something the size of a SSBN-type submarine across interplanetary space. Now consider that our hypothetical colony would actually be heavier, since SSBNs aren't rated for that kind of pressure, nevermind temperature. Now, factor in the problems associated with assembling it in place, assuming we moved it in pieces (trying to construct anything on Venus is going to be difficult, if not impossible, using even futuristic technology).
We can't. AC doesn't work on Venus. And this has nothing to do with engineering know-how. See:
http://en.wikipedia.org/wiki/Refrigeration
http://en.wikipedia.org/wiki/Heat_pump
You don't manufactor or extract coolant in order to cool something. At all.
Coolant is just used to transport heat from a hot environment to a cold one, then sent back to the hot environment to pick up more heat. Think of it as a conveyer belt.
More coolant, or fresh coolant, doesn't do the least bit of good. What matters is transfering heat to a heat sink, which can be done by recycling coolant. But in order to do any of this, you must first have a cooler environment to act as a heat sink. ACs and refigerators (and every other piece of technology we have for cooling things) use the outside air as a heat sink which doesn't work on Venus, since the outside air is 400 degrees.
http://en.wikipedia.org/wiki/Second_law_of_thermo
Heat cannot of itself pass from a colder to a hotter body.
Got it? There is no way to cool something unless you're venting heat into a colder environment. A closed system with energy in it will gradually convert all that energy to waste heat, while an open system on Venus will quickly rise to the same temperature as the air.
The only things I can even imagine serving as a heat sink on Venus are a shallow geothermic loop or a massive radiator fin in space. Geothermic loops may or may not work depending on whether it's colder underground than on the surface. Space radiators would work, if it weren't for the fact that we have no way to connect them to the surface (and don't even think of suggesting a space elevator - Venus has a rotational period that's slightly longer than a Venusian year, which precludes any sort of elevator).
Plus, for all the trouble you're suggesting we go through to avoid dealing with martian gravity, wouldn't it be simpler just to develop medical treatments for bone loss? That seems far less impossible to me than trying to live on Venus.
Lets say you want to build a shelter underground on Venus. You'll want it to be close to the temperature and pressure on earth, right? We're assuming that people are going to live here.
Well, temperature is the first problem. The rocks may not melt, but that doesn't mean they somehow stop conducting heat. Every single form of cooling technology we have just moves heat around instead of getting rid of it, and moreover this is a physical limitation, rather than an engineering one (damn pesky thermodynamic laws). You need a cool place to dump excess heat into. Where the hell are you going to put a heat sink on Venus?
Pressure is the second problem. Even if you were to build a shelter underground, the space contained within would still be the same pressure as the outside air (about 90 times that of Earth IIRC). If we depressurized it to Earth standard, then we'd be up against the problems associated with the oudside pressure bearing down on the shelter, which would crush it.
On Earth the only environment with a similar pressure is about 1 kilometer below the surface of the ocean. Have you seen what kind of engineering specifications are required for a craft that goes that deep and only carries a few people? Try and imagine building a base to survive that same pressure, plus the heat and corrosiveness of the Venusian atmosphere. Now remember that we're talking about a base that's going to be there for years, whereas the deep ocean submersibles go down for hours, and that the base is going to house some large number of personel, while submersibles carry typically no more than two or three.
Er, forget I said that...
If you look at what's happening in the US right now (election year, *sigh*) even with constitutional protection this sort of political monkey business still happens. Just take a look at all the violent video game laws that have been reported on
The primary problem is that there is no penalty for legislatures that pass unconstitutional laws, other than a waste of tax dollars (which doesn't affect them directly anyway). Instead you get laws that blatantly violate the first amendment passed, then struck down the moment they're challenged in court. This doesn't bother the politicians sponsoring the bills, because they can then claim to their consitutents that they tried to pass a "virtuous" law, but were blocked by "activist" judges.
Constitutional protections are vitally neccesary to prevent bad laws from being enforced, but they don't actually deter this kind of manipulative behaviour. And the cost is both to the judicial system, which gets demonized by political hacks for doing its job, and the taxpayer, who ends up footing the bill.
True that. Though I'd say that if there is something vastly more important overshadowing the effect you're looking for, then the effect that's being overshadowed is probably very small by comparison.
If C is making it impossible to correctly correlate A and B, then either C is much more statistically signifigant than A/B, or else the relationship between A and B is insignifigant enough that small entangled effects can make the connection between them unmeasurable. If it's the former, then I'd say we're making fine progress in stopping rape without kneejerk laws, whereas if it's the latter then porn is such a small contributer that trying to remove it isn't going to noticable affect the sex crime rate.
Of course, that assumes that there is a third factor overshadowing the correlation. My take would be that reduced sexual repression leads to both a reduction in rape and an increase in porn - in other words, that the correlative relationship is pointing to a larger overall change in society's attitudes.
Of course, no matter how you slice it, the law in TFA doesn't gell terribly well with the study linked by the GP.
Orbital decay only occurs when a satelite is within the atmosphere of the body it orbits. It's caused by air resistance sapping the satelite's orbital velocity.
Since the moon is essentially airless, this won't happen. You could (at least in theory) orbit as close to the moon as you like as long as your path doesn't smack into the side of a mountain. In practice, I'm not sure I'd want to risk it, but it's certainly not against the laws governing orbital mechanics.
Over extremely long time periods, you'd run into problems, since "essentially airless" is not quite the same as "totally airless" (even in deep space there is no true vacuum), but I suspect we'd be talking about decades at a minimum here.
True, but then again we don't have to prove a causitive arguement to debunk the basis for this law.
The woman advocating the law is stating that there is a relationship between porn and sex crimes. She is stating that the man who strangled her daughter was in some way either motivated or empowered by porn.
Now, correlation does not always equal causation, but as far as I know causation will always include correlation. Ie, you cannot have A causing B without also having A correlating to B. So, if her arguement were valid, then you'd expect a causitive relationship between porn and violence to coincide with a correlation between the two, right?
Now, what these studies show is a lack of correlation. In fact, they show an inverse correlation, which is exactly the opposite of what you'd expect. So either the mother has to be incorrect in her assessment of a sex offender, or else the researchers must be wrong.
Call me cold hearted, but I will take the word of a researcher over the word of an emotionally charged mother who has lost a daughter. Being traumatized by a criminal act does not grant you any degree of insight into a criminal mind.
The actions of a few sick and twisted individuals is not typical of the standards of society. Was dear old Jack the Ripper a typical 19th century gentleman?
The problem with your line of reasoning is the incontrivertable fact that violent crime rates have been steadily progressing downwards for decades, especially in areas like youth crime. It's not that there weren't sick and dangereous criminals in decades or centuries past, it's that they weren't as high profile. The fact that we have tabloids, CNN and legions of hungry journalists out looking for the next Manson/Jack/Son of Sam only means that we hear about such individuals more often.
It isn't lack of standards in our society that's the problem, it's an overabundance of boogeymen.
Civilization maybe? I knew that Sid Meyer guy was up to no good!